Thunderhead

Up-rate the bass drivers so they can take anything the amp can throw at them, even distorted. Yes, I know you're not supposed to distort a PA, and NORMALLY (assuming an intelligent sound engineer) it's actually safer to use less speaker capability than the amp can deliver so the amp doesn't get driven into distortion... but that relies on the sound engineer actually listening for the distortion and not doing it! If musicians are in control, you need to assume the worst . Pick bass drivers which can handle more than double the RMS power of the amp (per channel) - preferably even more - and if possible use one impedance step above the amp's minimum load too, so it cannot deliver as much power - ie use 8-ohm speakers if the amp can drive 4 ohms per channel, or two 16s if it's a mono amp with a 4-ohm minimum load... these are harder to find in PA type speakers though. Yes, this does reduce the efficiency of the system and you won't get as much volume as you think it should be capable of... that's the idea! If it matters, I've also done a lot of repair work for rehearsal studios over the years and this is the only guaranteed way to prevent damage, both for instrument amps as well as PA cabs. If you deliberately under-load the amp, you'll also help prevent power stage damage too. (Don't do this with valve guitar amps though, they don't like to be underloaded.) If this is not what they want to do (high-powered drivers are more expensive), you may need to modify the amps so there is a signal level pad (fitted internally) between the preamp and the power amp - this will stop the amp reaching full power if you arrange it so the preamp goes into distortion earlier than the power amp. This is a simple kind of brick-wall limiter, really. With all these methods you may still need to increase the protection on the tweeters too, since reducing the volume of the amp and making it distort sooner will still have the usual effect. Increasing the value and power handling of the crossover resistor will help - it will also reduce the HF response of the cabs which is probably an advantage in helping with feedback in confined spaces. As you can guess we are not talking ideal solutions for great performance and sound quality here . Just over-engineering to the point it's difficult to break things .

[quote name='Mr. Foxen' post='309687' date='Oct 19 2008, 10:21 AM']Guessing upgrading speaker is in order, reccomendations for an 18?[/quote]There aren't too many choices in 18s these days... Celestion only seem to do one, the FTR18-4080HDX (in the Pro Audio series), which is rated for 1000W but only has a sensitivity of 95dB - not that much, for a single-speaker amp of only 150W, even in an efficient folded horn. Eminence also do a couple, also in the PA rather than bass guitar range, and you definitely want the 650W Sigma Pro 18A-2 - which is much more sensitive at 99db and has a much better frequency range for bass guitar - rather than the 800W and only 96/97dB Omega Pro 18A or 18C which are pretty much dedicated PA sub drivers. [quote]The master volume is a bit odd (to me) its twelve points, clicky between them, and its mad crackly when clicking. Will get some contact cleaner in there, any other options there?[/quote]It may be the switch, but if cleaning it doesn't work it's probably one of the caps either before or after the control leaking a tiny amount of DC - this makes both pots and switches very noisy when moved. [quote]Right, housemate is up and we have rocked it. Is indeed quiet up close and loud far away. Initial knob twiddling wasn't that loud, until the sound of the kitchen being demolished became apparent.[/quote]Folded horns are always like that! I once tested a very similar Cerwin-Vega 18" cab in a friend's garden, with a Hiwatt 200 head - standing next to the cab, we thought the amp wasn't working properly it was so quiet. Then his wife came running out of the house shouting to turn it down . I went to the far end of the garden (rather a big one, about 50 yards long) and it was LOUDER down there! MUCH louder .

[quote name='stylonpilson' post='303618' date='Oct 10 2008, 09:51 AM']...and hence not a genuine Fender?[/quote] No. Some Mexican models, and in the later 1990s even the US Standard instruments in sunburst, were finished this way. But you're very nearly right about the plywood - in fact, the best description for these bodies is 'blockboard' - they're made of several fairly narrow strips of wood (roughly square, so each is about the same width as the thickness of the body), with a veneer facing front and back to hide the joins. On the front, the veneer is bent over the shaping of the body, which is possible because this is actually only a 'one axis' curve, and it allowed them to finish the front normally. But on the back, the 'beergut cut' is a two-axis curve and you cannot bend a veneer to that, so the veneer stops at the edge of the cut and the sunburst is used to hide it. If you're horrified that Fender should do this on apparently 'top quality' US-made instruments, you're not alone. Eventually it got them such a bad reputation that when the series was redesigned in 2000 (and changed from 'American Standard' to 'American Series') they stopped it and made a point of specifying a fully solid body in the literature. Not all these instruments sound that bad, but be aware that this is how they're made - I once saw a Jazz Bass from this series that someone had stripped to the wood, obviously without realising that it was made like this. Not only did it reveal the edge of the veneer on the back, he over-sanded the front slightly and went through the veneer in a couple of places... it was a real mess.

[quote name='rmorris' post='309040' date='Oct 18 2008, 03:13 AM']A tuner isn't really a 'pedal' though is it ? And I'd recommend branching off to a tuner from another pedal or the amp ( assuming it's a passive pickup bass else if it's active pickups you could branh off that too ) rather than going 'through' it.[/quote]It depends what type of tuner. The old non-pedal Boss TU-12 tuner for example has a low input impedance which is in parallel with the input jack at all times, and if you're going to it direct from a passive bass you need to be able to switch it out of the signal path entirely when it's not in use, or it's a real tone-sucker - even a simple 'tuner out' from something like a volume pedal is not enough as it doesn't actually disconnect the tuner. You need either an A/B switch, or something with a buffered output to drive the tuner. But the TU-2 - which certainly IS a pedal! - is the exact opposite, it has a very good internal buffer, so it's BETTER to go through the tuner. The only exception would be if you were using something like an old-style fuzz pedal (or one of the modern 'retro' ones based on them) - these often don't sound as good when driven by a buffer, so in that case you need to go from the bass to the fuzz and THEN to the TU-2. I also don't think you want to leave compression to the sound desk... that's giving control of your dynamics to an unknown unit with unknown settings (unless you're touring with your own complete rig and soundman), and even though rack compressors are certainly higher quality than pedal compressors they won't necessarily sound 'right' for bass. There will often be limiting at the desk to prevent overloads and distortion, but it will normally be set 'high and hard', so it just catches the extreme peaks and doesn't interfere with the dynamics of the music. I really don't understand the way a lot of bass players seem to care so little about what they sound like out front that many will allow the soundman total control - including often to DI the INSTRUMENT and not the amp, so what the audience hears can often bear no relation to what it sounds like on stage and what the player interacts with... as well as simply sounding like a bass pickup made loud, which to me is only half the sound at best.

[quote name='Shaggy' post='308671' date='Oct 17 2008, 03:26 PM']I confess to being the idiot doing the silver paper/fuse thing, just once, just to get me though a gig![/quote]Did it? If so, you're very lucky. It must have been a bad fuse (they do exist, although nowhere near as common as most people think when they say that meaning that it blew) or a momentary surge that didn't damage anything. What normally happens is that there is a fault with the amp, so the fuse blows. The musician then wraps the fuse in foil to 'get through the gig', and when they turn back on again the fault is still there, but the fuse can't blow this time, so something really expensive (like the mains transformer) acts as the fuse instead. If the original fault was something fairly trivial like a shorted rectifier diode this is a great way to turn a £20 repair into a £200 repair and STILL not get through the gig. Regardless of whether you did this once and got away with it - never, EVER do it again. Carry a spare fuse, of the same correct value as the original (never increase fuse values either, for the same reason). If the fuse blows, put in the spare and try the amp again. If it holds, you had a momentary surge or a bad fuse. If it blows, STOP. There is no point in doing anything else because the amp needs to be repaired, and anything you DO do will only make it worse. Lecture over...

[quote name='alexclaber' post='308145' date='Oct 16 2008, 08:51 PM']However, if you prefer the sound of a Class AB amp then there's little reason to go Class D etc to save weight - it's not hard to make a conventional bass head weigh under 25lbs which isn't a lot to carry. It's the cabs that make the difference when you're looking at going light.[/quote]Indeed - especially Neodymium speakers. (Which I do like, I'm not a total luddite! ) The weight saving on just one speaker is often as much as an entire transformer, especially compared to a modern lightweight toroid. Good cabinet design can reduce the weight too, but I always find that the really heavy ones somehow sound more solid and punchy. It's a difficult compromise, for me... I've yet to hear anything that I really like the sound of that I also don't hate the effort required to move. It would be nice if someone could crack it.

[quote name='Shaggy' post='308389' date='Oct 17 2008, 09:58 AM']Stonkingly good advice which I wish I’d known years ago. Just to confirm your observation on pre-amp valves; one of the three in my late ‘70’s Bassman 135 is “Fender” branded and so probably original, and the other two Mullards which I don’t think have been made for donkeys’ years – still going strong. So how would you know if the non-valve components were starting to fail (capacitors etc) – how would it affect the sound / operation of the amp?[/quote]There are often no very definite warning signs for cap failure (unless you can compare the tone to an amp where the caps have already been changed, which you will find makes it sound stronger and more punchy) - but any tech will tell you that old filter caps do often fail, and that it's better to change them before they do rather than afterwards as they can occasionally damage other parts, or leak nasty corrosive gunk everywhere. You'll hear varying advice on their life expectancy, but in my experience thirty years is a good point to take for when a routine cap job should be done - they can and do fail before that, but not very often. Up to twenty years I normally wouldn't bother unless there's strong evidence that more than one cap is failing. But this means that all Silverface and earlier Fender amps are now very nearly due or overdue. A lot of people (guitarists mainly!) seem to worry about it affecting the 'vintage tone' of their amps, but I've actually never heard an old amp that didn't sound better after a cap job, even if it already sounded great before! (Although 'better' is a matter of taste, certainly.) The resistors which are likely to need changing are the screen resistors and grid stopper resistors, because they get cooked by the heat of the valves - in fact, screen resistors often fail when a valve blows, and in a four-valve amp the owner often doesn't notice because although it stops the replacement valve working too (but doesn't damage it or blow the fuse again), that isn't obvious from the sound at least at lower volume - it is in a two-valve amp since then one half of the output waveform is cut off. Preamp plate resistors often go bad too - they drift in value and get noisy, and if your old amp is randomly hissing and crackling it's fairly likely that these are the cause. You need to use the proper original carbon-comp type for these to keep the 'vintage' tone, although carbon-film and metal-film aren't bad-sounding (don't use metal-oxides in the signal path though, they sound awful). I wouldn't change resistors ONLY because they've drifted a bit, but if they're approaching double the marked value they are definitely on the way out. If the pots have become 'scratchy' when turned, this is most likely NOT a pot problem! It's all too easy to change the pots to 'cure' this and find it doesn't, and then most techs won't put back the original parts (or at least not to the same standard of workmanship). If cleaning them with contact cleaner/lubricant doesn't work, it's usually caused by DC leakage through the tone stack caps. Old Fenders also have a nasty problem called 'board conductivity' which is when the waxed fibreboard eyelet board develops very slight (incrediby high resistance, you can't measure it directly) conductive paths through it which are enough to leak small amounts of current when subjected to the high voltages in a valve amp. This problem is difficult to identify - usually you can only be sure once you've eliminated all the resistors and caps, but the usual symptoms are also random crackling and noise, odd tone or in rare cases even instability and self-oscillation. Fixing it isn't always easy without quite a lot of work either. One other important thing to check in an old amp is the fuse - over the years many get 'fixed' with much too high a value, or at worst some idiot wraps a blown fuse in foil or sticks a piece of guitar string down the fuse holder to 'keep it working'. This just means that the next time something goes wrong, something much more expensive will fry instead. In fact with export-model (with the rotary voltage selector) Fenders in the UK, the labeled fuse value is too high anyway since it's a universal value that will work at 110V too - you're better reducing it to half the marked value for 240V, since it's the only protection the amp has (there's no HT fuse on old Fenders).

[quote name='karlbbb' post='308318' date='Oct 17 2008, 02:11 AM']Would you recommend the Boss LMB over say perhaps the BBE OptoStomp? I like the look of the OptoStomp, nice and simple, and I'd have it as an always on effect.[/quote]I've never tried the BBE, so I don't know. If you want it as your main sound, you should at least try to compare them though - I mentioned the Boss ones because they are the industry standard, easy to get, reliable, fairly cheap and do the job - but there are certainly better pedals tone-wise. I actually don't like the Enhancer function of the Boss LMB at all by the way, although the limiter is quite nice - because it has a threshold setting as well as ratio, you can set it so it doesn't mess up your normal playing dynamics as much as a simple compressor does.

[quote name='Subthumper' post='308229' date='Oct 16 2008, 10:43 PM']Hi folks I've just been offered a 77 Fender Bassman 100w head. Although it was initially brought to me for repair-needs a new set of valves and some resistors replacing-about £80+ ish to fix, I have no idea what its value is. Does anyone out there know what the value of these old beasties is? I'm very tempted as I've been hankering after a valve amp for some time. Cheers Just Ps Have just seen a completly original mint condition 1960 bassman combo on ebay. They are asking over £9000......[/quote] That's a completely different thing - although it was designed as a bass amp and can still be used as one (for a very specific, old-fashioned sound at pretty low volume) it's really a guitar amp nowadays, and is highly desirable for that. Even then it sounds like too much money. A 70s Bassman 100 head is worth, as Hamster posted, about £300 to £400 - possibly a little more if in fully overhauled and excellent cosmetic condition, but no more than £500 even for the very best example. This makes them among the best value for money valve bass amps. £80 sounds a little low to replace all the valves - there are four 6L6s and three 12AX7/12AT7s, although you almost certainly don't need to replace them all. In particular, do NOT replace the preamp valves unless they are faulty - the original US-made ones can very well be in perfect working order even now and will sound better than any new-production ones. The same even applies to the power valves if the amp has not been used that much, although they do wear out somewhat faster - but again, original US-made 6L6s outperform and outlast any more recent versions. It's a complete myth that valves need replacing 'regularly' - they don't unless the amp is being used VERY regularly. But, if the amp is a '77 and has never been overhauled, you should budget for replacing the filter caps since they will be at the end of their life expectancy and could fail without warning. Electrolytic capacitors DO degrade simply with age, and actually worse if the amp has not been used regularly than if it has. Even if they don't fail, you will get better performance from the amp with new ones (especially for bass - some guitarists like the sound of tired caps). You need to replace all the caps in the tray under the chassis, the bias cap on the little board near the power light, and if you're being really thorough, all the preamp cathode caps on the main board. Don't replace any non-electrolytic caps unless they're failing. This job is about £100-worth too. The resistors that need replacing are most likely the power tube screen resistors, and it's a good idea to at least check the power tube grid stopper resistors while you're at it (these are the smaller ones under the screen resistors and easier to get at when those are out) since these can also crack with the heat from the valve over time and if one fails you will blow the valve. If in any doubt, replace them. Use modern metal-film, metal-oxide or wirewound resistors for the screen resistors and metal-film or carbon-film for the grid stoppers - these are much less prone to heat damage than the original carbon-comp type. Changing them does not affect the tone in this location. Hope that helps! (I do this sort of work professionally by the way.)

[quote name='cd_david' post='240803' date='Jul 16 2008, 12:54 PM']Aren't we getting away from the fact that fenders are a MACHINED body and neck held together with either 3 or 4 screws? Its not alchemy. The only variations are wood[/quote]No, not quite. Through the 70s, both the final shaping of the bodies became cruder, leaving them less deeply contoured and squarer-edged (and so heavier, even given the same density of wood, which did also generally get heavier), and the finish changed, becoming thicker, harder and also heavier. The late-70s 'Thick Skin' (Fender's own term) finish actually weighs a significant amount, as you will notice if you ever strip one to the wood! The result of both these things is that the late-70s instruments are noticeably clumsier in shape and feel, on average, and usually harder and brighter sounding. You do get the odd good one but they become rarer the closer you get to 1981. The actual QUALITY didn't fall too badly in many ways, it's just that they were made 'wrong', without understanding what it was that players liked about the older ones. What's hilarious is that these instruments (and 70s Gibsons for similar reasons) are what started the whole 'vintage' market by being so inferior to the old ones to most players, and now they are considered 'vintage' too, just because they're thirty years old! Although to be fair, they have usually improved a bit with age, and some of the more recent production wasn't exactly great either.

[quote name='alexclaber' post='308009' date='Oct 16 2008, 04:57 PM']I'd love to see a blind ABY test to see if you really can always identify the Class D amps from Class AB ones. Can you hear a difference between mains frequency transformers and SMPS's as well?[/quote]No, I don't think so - not tonally, anyway. They don't seem to have quite the power delivery though - but maybe this is also to do with smaller filtering values, ie not directly related to how the DC is derived. Either way they don't seem to have the presence and punch that traditional designs do (which is more a function of the power supply than the output stage). I knew this would be controversial, but it really isn't just me - read the thread on the Trace AH250. I'm not the only one that thinks there is an easily audible difference, and that the old-school mains transformer/larger filter/Class AB amps simply sound better, and louder for their rated power. If you really don't hear the difference, and are happy with a Class D amp, that's good for you - they're lighter and cheaper than equivalent quality and power Class AB amps. But don't deride people who can hear the difference - and I would be willing to take part in a blind A/B test too. For what it's worth, I did once take part in a blind test via mp3 files (which is hardly the most revealing format) involving digital modelers vs. analog solid-state and valve guitar amps... and I scored 16 out of 17. I'm certain I would have got the other one if the equipment had been there in front of me too. And yet there are other people who claim that the difference is marginal, or doesn't make enough difference to be audible in a mix, etc etc, just as there are those who can't hear the difference between traditional output stages and Class D. I would just hate to see Trace Elliot go down that path when the whole reason I liked them in the first place was their great tone, and it would be a shame (for me, anyway) to sacrifice that for the sake of light weight or following some new fashionable trend. I'm not just an 'older is always better' snob either - when Trace first came out, THEY were the new breed and a lot of players stuck to their old valve amps and earlier more traditional-sounding solid-state amps. Still, perhaps it doesn't matter... since there is plenty of old Trace gear to go around for a long time, and it's pretty reliable.

I would get three pedals: A tuner A compressor/limiter An EQ Boss make industry-standard, high quality versions of all these (the compressor is called the Bass Limiter-Enhancer, and you want the dedicated Bass EQ; the tuner is the standard TU-2). If you're not wanting anything more radical than a simple clean bass sound you won't need more than that for any situation. You don't really need a DI box if you use modern-type pedals like Boss since they all have built-in buffering and will happily drive any amp, desk or length of cable (or DI box, on big stages where the soundman will probably want you to use his one anyway). I think that high-quality individual pedals do sound better than cheap multi-FX units too by the way.

Not only is the difference between .047uF and .05uF inaudible, it's also within the 'tolerance' (allowed variation from the intended value) of normal capacitors, which is +/- 10% (or even +/- 20% with some types). So in fact a particular .05uF in the lower part of its tolerance range could even be a smaller true value than a .047uF in the upper part of its range. In other words, it doesn't matter! It's effectively the same value. You will have difficulty finding .05uF these days anyway, since .047 is the modern 'prefered' value. (There is a technical reason why such an apparently odd number is chosen, which is also to do with tolerances and the overlap between one value and the next.) So you need: Treble pot: 0.047uF Bass pot: 0.0047uF This 10:1 size difference is important, or one of the controls won't do much - don't use the same value for both! It doesn't matter what type, and there is no minimum voltage rating requirement (50V is plenty, and is the smallest normal value for non-electrolytic caps). Ceramic, polyester, mylar, mica, polypropylene etc all will work fine.

[quote name='Crazykiwi' post='307634' date='Oct 16 2008, 09:34 AM']Sounds good to me though I challenge anyone to tell the difference between solid state Class A, A/B, D, G or whatever on stage during the middle of a set. Everything else being equal of course. I think Trace should whack together a few wedge cabs with 12 and 15 inch drivers.[/quote] Between Class AB and Class D? No problem at all. Any situation, any volume, anywhere. Not quite sure in a recording but I would guess so too. If you really don't hear it, I have no idea how! But we all hear things somewhat differently, so I don't doubt there may be those who can't... or who can hear a different thing that I can't. I don't think there is a significant audible difference between Class A and Class AB by the way (despite guitar-amp snobbery on the subject, most of which is based on a misconception of what Class A means, and there are very few Class A guitar amps - and I would guess NO Class A bass amps, in fact), but Class D is a whole different way of producing the output waveform, and it's VERY audible, to me. Class B and C are not suitable for audio because of the large amounts of crossover distortion they generate, if you were wondering where they went! [quote name='Merton' post='307648' date='Oct 16 2008, 09:44 AM']As you say, mid-soing mid-set it's just a bass sound, no-one else cares anyway![/quote] No... it's the difference between something with actual TONE as well as low frequencies, and a sort of artificial approximation of it. Other people may not THINK they care, but you'd be surprised how the quality of the sound is noticeable even to non-musicians - they won't be able to put it into technical terms, but they will still be able to tell the difference between 'great sound' and 'not so great sound'. I feel exactly the same about digital modeling and there are many people who think they can't hear the difference there either. Although Class D does not stand for 'digital', and the output devices are still analog, nevertheless there are similarities in the way the waveform is produced.

[quote name='EBS_freak' post='307537' date='Oct 16 2008, 02:22 AM']Do you think that the Class D stuff doesn't sound as good either?[/quote]I don't think it sounds good at all.

'Groundbreaking lightweight' as in "lighter than normal but actually has some (or any) tone"? I wouldn't mind some slightly lighter Trace gear but I really hope they haven't gone down this switch-mode/Class D 'ultra-light' route. Neon pink I could like, though . (Provided the amps sound good!)

I actually only have one bass, and I do gig. But it does have one slight 'cheat' - it's a Rickenbacker, so if the jack ever breaks I can use the other one! (OK, that means bridge pickup only with a mono cable in it, but it would do.) In fact, proper US-made Switchcraft jacks are extremely robust and it's very rare to break one. I know major accidents can happen - and something like dropping it and breaking the headstock off would certainly be a problem! - but I just rely on keeping everything checked and in good order, being careful, and taking some basic tools with me. I don't like taking a second instrument because it's more to carry, more to risk being nicked (especially as the more you have, the more trips to/from the car and so the more difficult to keep an eye on it all) or knocked over... and to be really honest, I think taking too much stuff to a gig makes you look a bit pretentious anyway - sorry! Yes, if I was in a professional band on tour of course I would take a backup, or possibly the 'magic 3' for exactly the reason posted above - when you're on the road it's not always as easy to get stuff repaired immediately. But I'm sure there are many bassists who have gone through their entire careers with only one instrument. I play guitar too by the way, and I apply the same rule there - I have to laugh at a lot of guitarists who seem to take half a dozen different ones to even tiny gigs because they 'need all those tones' - and yet sound almost the same on all of them .

The Hughes & Kettner Red Box will work - it's designed for guitar and the two simulations are called Combo and 4x12", but they're not exact representations of any cab and really I would just call them 'brighter' and 'fuller'. Unlike with a valve amp, you don't need to provide a dummy load on the power section of a solid-state amp, so you can connect just the Red Box to the amp. A standard passive DI box would almost certainly work too (although without the cab tone curve), if you keep the amp at low volume. I'm not sure I would try it with an active one as the circuitry might not like the voltage levels at the speaker output. I had an old passive box with a multi-level resistive pad at one time, and this definitely worked fine - I gave it to another bassist exactly for this reason, for DI'ing an old valve amp on stage. Either way, you need to keep both the master volume on the amp and the gain on the recorder way down until you know what sort of signal level you're getting. It's unlikely that even a very loud signal will damage anything as long as it's not coming directly from the output of the amp though.

[quote name='dave_bass5' post='307110' date='Oct 15 2008, 02:21 PM']Ive not had any issues but reading this thread makes me think i need to stop using the XLR on the desk.[/quote]Don't worry, you'd know by now if there was a problem. The damage will most likely occur within a few seconds of the first time you use it, if it's going to. Why anyone would design an XLR output on an amp that cannot be connected to a system where phantom power is likely to be present, without damaging it, is beyond me - it's just basic bad design. But they do... Even when phantom power was not 'commonplace', it has always been a feature of some balanced systems and so it could never have been expected that an amp would NEVER be exposed to it if DI'd.

If you have a compass, bring it close to each of the pickups and see which way the needle points at the pickup. If the pickups are RWRP, it will be north for one and south for the other. If the same (either north or south) for both pickups, they aren't. If you don't have a compass, probably the easiest way is to remove one pickup from the bass and place it face down to top of the other one - if they're RWRP they will stick together face-to-face; if not, they will repel. (This is sometimes difficult to tell for sure, if so try putting the back of the pickup on top of the other one - it should then stick strongly.) The capacitor for the tone control is probably the one part you don't need to change. Contrary to popular belief the type or brand of cap makes no difference to the tone (controversial I know, but I've done a fair bit of careful experimenting on this - not simply swapping and listening, when it's easy to fool yourself - and I'm really sure). But if you buy the pre-packed Fender pots, you get a new good quality tone cap anyway. If not and you can't salvage the old one, any .047uF will be fine. The type of cap does make a difference in AMP circuits by the way, but this is a completely different thing because the voltages they're subjected to are hundreds of times higher, and this is what causes the differences in tone. At passive guitar or bass voltages, it simply doesn't occur.

Are the pickups a RWRP (reverse wound, reverse polarity) pair? If not it will certainly be noisy when either or both pickups are turned up - it sounds like it must be this or the noise would go away when both pickups are up full. I can't remember about the Japanese Jazz basses, but the stock pickups in a couple of other Fender Japan guitars (Jazzmaster and Jaguar) which are supposed to be RWRP and always have been on American models, aren't. Personally I've never thought the pickups and wiring were the strong point of the Fender Japan instruments, on any model - the woodwork is excellent, the hardware is good, but the electronics are average at best. I would replace the whole lot with proper US-quality parts - Duncan or Fender US Reissue pickups, CTS pots and a Switchcraft jack (yes, everything). The pots and jack are available as Fender spares if you can't find them anywhere else, although they're expensive that way. That will give you a much better tone as well as probably curing the noise problem.

[quote name='redstriper' post='306604' date='Oct 14 2008, 08:17 PM']BTW - can you tell me the mains fuse value for my TE AH 150 ?[/quote]T2A. [quote]I was recently advised that the Trace combo is outdated and ineficient and that I would get more deep bass and volume from a modern lightweight rig. I tried markbass, aguilar, ashdown, epiphani, hartke and bergantino amps, cabs and combos, none of which had the warmth or volume of deep bass as the old trace.[/quote]That's how I feel too - wonder what it is the 'new guys' are hearing? Not the same as what we are, anyway . [quote]I still yearn for more oomph at bigger gigs with no PA and am considering adding another speaker - maybe a 2 x10 or another 15. It would be nice to get the sound and feel of an Ampeg 8 x 10 (my favourite cab) in something I can carry.[/quote]That's going to be difficult. The sheer mass of that cab is part of the tone - the 4x10"s they do sound similar but weigh a ton too. Really, it would probably be as cheap and no more weight just to buy another old Trace combo (they did 4x10"s in the same series) and link them together . [quote]Which mesa cab do you use ?[/quote]I think it's called a 1516, or something - it has a 15" 300W EV, a 10" 150W EV, two 6" 75W Eminences and a treble horn (which is blown, so I don't use it). The way it's hooked up is either crude or clever, depending on how it was thought up! There is no crossover, it relies on the different impedances of the drivers and their natural tonal response to split the power and the frequencies correctly - but this means it has none of the efficiency losses or phase errors that you get with crossovers, so it's very loud and direct-sounding - and although it's 'full range', it's certainly not 'hi-fi'. It's the same basic cab as Paul McCartney uses, but his is the 'soft trim' version (because it will be flightcased), and mine is the one which IS the flightcase! - it has the hard-faced ply, steel edges and stuff actually part of the cab. Which no doubt makes it even heavier - I'm not a big guy and it weighs exactly the same as me (135lbs), which makes it a real bind to move since I can't lift it without leaning right back, and it has some of the most uncomfortable handles I've come across too - even between two people it's a pain. So it rarely leaves the house, which kind of defeats the point... and I end up using whatever cab the venue or the other band has, which is usually less than ideal. I have been thinking about a pair of Trace cabs from the same series as my AH200 - a 1x15" and a 2x10"+2x5" - which should be perfect in theory, but they're surprisingly heavy too, especially the top cab - they also have internal baffles, and they're made of MDF which is denser than ply (and which I don't really like, either - it seems a bit toneless). So I may go back to the older ply-series cabs which I had with my former MkV AH250, which I sold because it was getting a little rough, the fan was starting to grate, and the little Series 6 AH200 was very nearly as loud for half the size and weight... except that it isn't, quite - it's not bad but still lacks a little of the huge depth and fullness of the old one. Either that or I'll just go completely over the top and find an early AH500 . There is still nothing like the tone of the old Traces, to me.

Amazingly considering that I have three of these and use them for guitar, I've never thought about using one for bass - and I use plenty of effects on bass too, including some guitar pedals. I must at least try it! For guitar, this is one of the best and most maligned pedals ever made, in my opinion - a lot of people seem to think it's more or less a toy or a gimmick. One reason for this may be that it's quite tricky to use well, but once you do get the hang of it you can do things that no other pedal will, both 'simulated feedback' (not identical, but usable) and weirder things like drones and near ring-modulator sounds. It also sounds great - it's not actually a DS-1 circuit, although that is often assumed. If anything it's a bit closer to a Rat, and like it the tone knob is quite interactive with the distortion level so you have to be careful to work with both of them, and the best settings are mostly below halfway on both. If I had to pick just one guitar pedal, it would be one of these - in fact I do, when I want 'one pedal in a pocket' for jams and open mics. [quote name='BigRedX' post='225586' date='Jun 24 2008, 07:37 AM']You do have to be careful about note tracking though - pick the wrong moment to hold down the pedal and the resultant "feedback" note is horribly out of tune.[/quote]Very true, but that's part of the charm of it - you can deliberately do that once you learn how to get it right when you want it, and then not when you don't... But this is a bass forum, so enough of that .

Yes, that's right. If it makes it easier to wire up, you can connect the two wires to the Bass pot the opposite way round (to the same two terminals), it won't affect the operation.

[quote name='redstriper' post='305743' date='Oct 13 2008, 07:50 PM']Thanks again, do you know where I can buy spare fuses - these haven't been replaced in 23 years and it might be a good idea to have a couple of spares just in case.[/quote]Maplin Electronics is probably your easiest, unless you have a small independent electronics/hobbyist type shop where you live. [quote]The Selmer was mad loud and incredibly full sounding. My 15" speaker could barely cope with it and I felt like it needed a lot more speakers to handle it. To be fair, it probably wasn't louder than the Hartke LH 1000 or maybe even the others, but it was the only one I felt likely to blow the speaker out of the cabinet if I turned up the volume and it just felt like a Harley compared to 3 mopeds.[/quote]Valve amps often have that sort of sound - they have much lower damping than solid-state amps, which means the speaker is freer to move when the amp DOESN'T tell it to! So it can get a bit out-of-control sounding and woofy when pushed hard. This is one reason they sound loud too, but it doesn't always translate into real volume in a mix because it tends to muddy things up as well. For guitar, where the notes are much further away from the resonant frequency of the speakers, it makes them sound nice, but for bass it doesn't work as well. This is one reason many valve bass amps work best with smaller speakers, and some (eg the Ampeg SVT) were purposely designed with a tightly sealed cab to provide the damping itself (their 8x10" is actually four sealed 2x10"s in the same outer box). Solid-state amps are capable of controlling larger speakers much better. [quote]The combo speaker cab is a quirky Trace design, narrow with an internal panel behind the driver and a massive front flared port. I was told that a more modern and larger cab would sound better[/quote]Hahahaha . Those old flare-front Trace combos sound fantastic. It's a highly efficient as well as great-sounding cab that really makes the most of the relatively low power of the amp and the single speaker. Good luck finding anything more modern that does as well, let alone better . [quote]I wonder where all the advances in cab design from the past 1/4 Century have actually got us! The more modern gear I try, the less impressed I become.[/quote]Smaller and lighter cabs with greater power handling and a cleaner and more even frequency response, mostly. Laudable goals in a technical sense, but do they actually SOUND better? I don't think so either really... That's why I still use an old 200W Trace and a giant Mesa cab I can barely move! Which makes the amp sound about twice as loud as any more modern cab I've run it through, plenty to gig with even with an amp considered underpowered by modern standards... but which I would still probably like to replace with a smaller two-cab rig when I can find the right ones - I'm getting old and the thing weighs as much as I do (literally).