Beer of the Bass

[quote name='Abominathan' timestamp='1494000016' post='3292533'] Ever since I've owned it yes, never had a problem but that doesn't mean that it's set up 100% how it maybe should/could be. [/quote] I'm not very familiar with Laney amps, but in a lot of EL34 amps the bias supply needs a few resistor values changing to run optimally with 6550s. Of course, this might have been done already - it would just need someone to check the bias and see if it's in a reasonable range for the 6550s. Chances are that if it's run well for years, it may not be far out. [quote name='stingrayPete1977' timestamp='1494023474' post='3292761'] What is it they say about "one man's treasure"? I've got a bad back just looking at it [/quote] Ach, a valve amp this size isn't so bad, and can be a fun thing to have around. I probably wouldn't be committed enough to cart an old-school 4x12" around myself, but I'd cheerfully have a head like that.

It looks like a nice bit of kit, with those Partridge transformers. Has it always had 6550s in there? I'd expect to see EL34 in a 70's British 100 watt amp, and the bias requirements are a bit different for 6550s.

Chromes are at the stiff feeling end of things, for a given gauge. I wouldn't describe them as similar to Thomastiks in many ways.

I had an oil can guitar a few years ago, bought on a whim. Mine was made from a can of Unipart brake cleaning fluid. It was kind of entertaining, but it was about the most uncomfortable thing imaginable due to the shape and size of the can. They could be a fun wall-hanger perhaps, but to actually play one seems like a bit of an affectation unless you have a genuine need to cobble together an instrument from scrap materials.

So this is a piece of sculpture the shape and size of a double bass, which is not a double bass? Like, a genuine Bass Shaped Object? I suppose it's an interesting idea, in a Magritte's pipe sort of way...

[quote name='leschirons' timestamp='1493729641' post='3290187'] Sorry, I thought you said dessert rock. [/quote] Dessert rock? Like The Sweet?

I saw a baffling guitar advertised on a facebook group today. It was an Ibanez semi, with a distinctive small body shape that isn't copied from any Gibson model, and recognisable Ibanez hardware like their slotted tailpiece, but with the headstock reshaped and rebadged to resemble a Gibson headstock. Why would you do that?

[quote name='OliverBlackman' timestamp='1493316809' post='3287470'] Jaco only needed 4 strings...... [/quote] Apart from when he used his 5 string! OK, he didn't record or gig with it a lot, but if Jaco can dabble with a 5, we can put that line to bed. [url="http://www.youtube.com/watch?v=5n_PFMrCkY8"]http://www.youtube.com/watch?v=5n_PFMrCkY8[/url]

If your 4-ohm 2x10 uses two 8 ohm drivers in parallel (which it almost certainly will), you could rewire it with the drivers in series to become a 16 ohm cab. Then both cabs together would be a 5.3 ohm load with the 2x10 using half as much of the amp's power as the 4x10, which seems ideal. You would want to disconnect any crossover and tweeter components in the 2x10" if you went this route.

The last proper Jazz I had would have looked like the OP's picture when the controls were at 100%, and that was how it came from Fender.

I'll probably take a single 12" cab out for my Sunday gig this weekend with an 80 watt valve head and vocal PA only, and I expect that to work out just fine in that setting. But that's for a chilled-out set in a family pub on a Sunday afternoon where playing at rock volumes wouldn't get us invited back. I do have a second cab that comes out sometimes (in a larger room or when drunk people are dancing), and the pair of them are noticeably bigger sounding though I don't own any amp more powerful than 200 watts currently. My cabs could be described as a typical 1x12" (with around 250cc displacement) rather than some of the more capable 1x12s, so I would not be surprised if a more powerful amp on the right modern 1x12" could do the same job.

[quote name='Bigwan' timestamp='1493193012' post='3286297'] I don't know much about Monique. Do you know what topology Jule uses for the midrange control? Similarly I'm clueless about his sensitivity control. I'd assumed it was just a simple gain, but reading between the lines there seems to be something else going on there. What topology did you use for your midrange control? Is it similar to this: [url="http://www.angelfire.com/electronic/funwithtubes/images/Amp-Tone-7-A-A.gif"]http://www.angelfire...-Tone-7-A-A.gif[/url] I can't see any pics from early in that thread unfortunately, although I've read it at some point in the dim and distant! [/quote] The EQ in the Monique has been described as a Baxandall, and from what I've read about it I'd guess it's probably a true, active Baxandall circuit. Jule is a little cagey about how the Sensitivity control operates (quite understandably), though he hints that it also affects the input impedance. Without knowing what topology he has used for the input stage it's hard to be certain what's going on there, though it does look like he's come up with something fairly distinctive rather than borrowing from the same classic designs most other people do!

[quote name='Passinwind' timestamp='1493142810' post='3286032'] There's an old Talkbass thread on a couple of my 6SL7/6SN7 builds: [url="https://www.talkbass.com/threads/a-diy-tube-preamp-line-driver-by-passinwind.345415/#post-4388452"]https://www.talkbass...5/#post-4388452[/url] Some of the pics have gone missing in the thread due to the TB software changeover after I posted them but I can probably scare them up if anyone is interested. JGR is a good friend of mine and it's well worth gleaning what you can from his posts over there too. I opted for an active bass and mid format, closer to the Jule Monique's approach than the Ampeg thing. [/quote] That does look nice, and it looks like a deeper design process than I'm getting into since I'm essentially pilfering sections of existing amps in a building-block approach. I should probably look into SPICE modelling at some point... I'll be using less premium parts than some of your builds - no PEC pots for me! I'm going to make up eyelet boards for the power supply and high-voltage bits of the audio circuitry, though I might put the resistors and caps for the James tone stack on a little perf board mounted on the back of the pots to save some space, since those are low-voltage parts.

[quote name='Bigwan' timestamp='1493105252' post='3285549'] I've most of the parts for a similar build just waiting for me to free up enough time to start building. I digested quite a bit over on the other forum, particularly from username JGR, who builds under the name Reiner Amplification. His bass preamp has an inductor midrange, based on the Ampeg V9 topology, probably similar to the V4 going by your description. His earliest designs had lower and upper midrange controls using wah inductors! In the end up I decided to start with the B15n pre, simple as it may be, but add a sweep control to the tonestack, a la Arkham Zephyr [url="http://arkhamsound.com/zephyr.html"]http://arkhamsound.com/zephyr.html[/url] I can always revisit later and add an inductor midrange. I have a multi-tap carnhill inductor at the ready! [/quote] Yes, the V9 looks like the same midrange circuit I'm thinking about. I wasn't aware of the Carnhill inductors - having just googled them, that could be an option if I can't get a hand-wound inductor to work. I found this page which describes making a copy of the Ampeg multi-tapped inductor; [url="http://www.frontiernet.net/~jff/SonOfSVPCL/DIYSVTBassPreampInductor.html"]http://www.frontiern...mpInductor.html[/url] I have found a ferrite core of the same size with an AL value close to the one he used, I've calculated how many turns I should need, and now I just need to borrow an LCR meter to check that I'm in the ballpark of the right values. My build will essentially be a B15 preamp, followed by the midrange stage and an AC cathode follower on the output.

Would you consider a Hofner to be conventional? Some of those are crazily light.

I'd rather use a proper DI box than follow those instructions for a simple resistor divider, as with a DI box you usually have tranformer isolation between the amp and PA and a ground lift switch in case of hum. Also, sound guys tend to be much happier taking a line from a familiar looking DI box than some home-built contraption! I have an older BSS AR116 that can do this (with the 40dB pad engaged), though it's an active rather than a passive DI, and obviously you still need a speaker to present the correct load to the amp. I think the current BSS models are quite pricey though. I think the cheapest DI box that claims to be suitable for this use is the Behringer DI100. There are also dedicated guitar speaker level DI boxes from Hughes & Kettner or Palmer which offer speaker simulation on the DI output. This might be handy to take the edge off if you're using overdrive or fuzz sounds, but maybe less useful for clean bass.

The external linings, gamba corners and the tuners are very much like instruments I've seen attributed as about 1900 (or a couple of decades either way), German or perhaps Czech. Is it a beech neck too? Many of these basses were never marked with makers names, so you might not get any closer than that.

I have a GK MB200 with a single volume control, and I reckon that a second volume control would be useful not so much for pushing the preamp into overdrive but for improving the signal/noise ratio when used at low volume. GK tend to voice their amps so that the highs are quite strongly boosted already with all of the EQ knobs at noon, and the preamp volume is early in the circuit, before the EQ. This does give them quite a lively character, but the extra gain in the highs can make them a bit more hissy than a flatter voiced amp would be. (Though I've not heard the Fusion 500 - maybe it's quieter than their op-amp preamps).

After having played around with building a B15n style preamp into my old Dynacord hybrid head; [url="http://basschat.co.uk/topic/277312-new-old-amp-day-dynacord-eminent-ii/page__view__findpost__p__3252758"]http://basschat.co.uk/topic/277312-new-old-amp-day-dynacord-eminent-ii/page__view__findpost__p__3252758[/url] I have found that I really like the sound of that particular preamp circuit and I've started thinking it would be a handy thing to have a similar sounding preamp I can use as a standalone unit and plug into other power amps. A good DI output would be useful too. I also have a good few of the parts I'd need hanging around already; I have some valves in the stash, a neat little toroidal power transformer and a couple of salvaged audio transformers I can try for a DI output. After mulling it over for I while, I've worked out what I want to build. The B15n preamp circuit sounds great, but with only bass and treble controls the EQ is not very flexible. I've been reading up on the inductor-based active midrange used in the SVT, which seems attractive apart from the high parts count. But there is a more economical version of the Ampeg midrange circuit used in other amps like the 90s V4BH which uses only one triode for the midrange, with the other half of the valve used for a cathode follower for a low impedance output. The multi-tapped inductor used by Ampeg is a proprietary part which is hard to find, but I have found a useful set of instructions on how to wind my own. So the rough plan is to have a 6sl7 valve for the initial gain stages (with a pre volume and bright switch in between), a bass/treble James tone stack, then an ECC82 for the active midrange and cathode follower output stage. That should be able to feed the jack output directly, with a transformer for the DI out. If I take some care over the layout, I think I can get it into a small project box of about 250 x 170 x 50mm, which should stack quite nicely with most micro heads. I thought about using a 1U rack case, but I have never got into the habit of using rack gear. The first thing I'm going to attempt will be winding the inductor for the midrange, as the rest of it depends on whether I can do that successfully...

[quote name='BigRedX' timestamp='1492699899' post='3282503'] We haven't sold anything like as many T-Shirts as we have CDs and records, but our T-Shirts sales have made a profit for both designs unlike the music which has yet to sell enough to cover the recording, and production costs for any of the 4 releases. It always seems strange to me that people will happily pay £10 for a T-Shirt that probably cost less than £3 to produce, but aren't so keen to spend the same on an album whose unit cost will be considerably higher. [/quote] It's not impossible that our t-shirt art is better than our music, though that's probably a thought I should not bring up with the band!

When I buy music from independent artists I prefer a hard copy if at all possible, but I will download if that's not available. Though having said that, the band I play guitar in have had a surprising number of younger people come up to us at gigs, look at the CD's and pronounce that there's not much point since they don't have anything to play it on. That always makes me feel old, and I'm only 36! Typically we shift more t-shirts than CDs at gigs...

[quote name='mcnach' timestamp='1492631507' post='3281892'] he's not wrong! [/quote] What happens if you do? I'm curious now!

Is bass much welcomed by the Morris crowd? My brother used to know a few down in Gloucestershire and Somerset, and he reckoned that any attempt to play chords to the tunes was frowned upon - his local lot were all melody instruments and the odd bit of percussion (apart from Melodeon left hand which is on the wrong chord as often as not anyway).

Hmm, it's elegant if you ignore the pointless extra holes drilled in the top and plugged with grommets, the preamp that does nothing and the big hunk of end-grain scrap wood secured with honking great screws through the back!

[quote name='mcnach' timestamp='1492368679' post='3279730'] During the RATM set, a drunk guy climbed onstage... singer handled him well, let him jump a bit and then his friend came to pull him out, no harm. A little while later, the same drunk gets his willy out and starts pissing on the floor in front of the stage. He was promptly kicked out... but wtf??? [/quote] Ooft! Was that Whistlebinkies? We've played there a few times in recent weeks, and it does seem to attract some boozy punters. This has good and bad sides, I guess.