Subthumper

Hi, not seen one of these since I sold my old one back in 88. I learned to play on it. It was a state when I got it and I did a refinish in Ford midnight blue and grey pickups. I thought it looked the mutts nuts when I was 17. Cost me £40 and my old fishing rod at the local 2nd hand shop. It played pretty well as I remember. Played it for hours. Good work hope it goes well. Cheers Just

[quote name='Ian Savage' post='966669' date='Sep 24 2010, 01:37 PM']Just curious really, I'm looking at getting one of these as part of a gigging six-string rig and looking at the specs they've got a power handling of 400W RMS, 800W program (which is higher than some bass cabs I've had!), but I strongly suspect that being semi-open-backed they won't have very much 'wallop' for bass duties (only at jam nights and such, nothing properly high-volume). Anyone ever tried it, or run bass through any other kind of open-backed cab? Cheers all![/quote] Hi, I think you'll find thats a guitar cab. Putting a bass through it will most certainly blow the drivers due to the open back design not putting any load on the speakers and cause them to over travel. Also being a guitar cab will mean the drivers will be high resonance and not make much bass anyway. It might work as the high cab in a bi amp rig though. Cheers Just

[quote name='thebassman' post='961042' date='Sep 19 2010, 11:39 AM']Modern transformers, like in the 400+, are far more reliable, so unlikely to be this. On my 400+, my tech narrowed it down to the standby switch. It had been blowing fuses for a while. The switch was letting too much current through, he checked it with a multimeter in line. I strongly recommend you don't do this, unless you know what you are doing. Lots of voltage and current!! Anyway a replacement was only £15 from westside.[/quote] Hi I dont wish to sound like your tech did'nt fix your amp but how does a switch pass too much current? Is'nt it more likely that the switch had become intermitant and that was blowing fuses?

[quote name='pete.young' post='954006' date='Sep 12 2010, 08:45 PM']Absolutely. Welcome to Basschat, Mike. Please ignore the peanut gallery. I'd like to hear your thoughts on the JJ KT77 . I have them in my Pro 4000 and Pro 2000 and they seem to do a pretty good job.[/quote] The JJ's seem to be pretty tough. A friend of mine techs for Killing Joke and we put JJ's in Geordies amps. If he cant break them then I say they were good enough for anyone. The rest of the JJ stuff seems pretty consistant too, I've been using them for most of my amp servicing work with very few problems. The thing with valves is that there is an allmost endless list of brands but only a finite number of actual manufacturers which must mean that in many cases your buying the same thing in a different box with slightly different bulls**t written on it.

Interesting stuff. No problem getting KT77's , JJ now make one and its very good. Probably would sound good for a bass amp as they seem to be halfway between a 6l6 and an el34. Would love to get my hands on a Burman.

[quote name='woodyratm' post='934849' date='Aug 24 2010, 02:46 PM']I gave the dude a call - He said it [i]might [/i]be the valves. Wasn't able to confirm either way if replacing the valves would fix it - he did say that the lower output did sound like the valves had died on one row. Looks like this is the way forward. Might see if i can book it in one of the local shops as soon as possible for them to check it. Just a shame that it'll cost silly money to do it! Though at least Watford Valves sell the right valve needed![/quote] If a shop is going to sell you a set of valves then they should'nt be charging too much to test your old ones. At least valves are easy to take out and test. I recently repaired a large transistor amp that had blown some of the output devices and I had to dissmantle most of the amp to find out which ones it was. This took some come considerable time and mess ( I hate heatsink compound) and the replacement transistors were'nt far off the price of some of the lower cost valves. If its not valves then maybe its the smoothing caps. That might be my next port of call. Cheers Just

[quote name='woodyratm' post='933996' date='Aug 23 2010, 06:30 PM']Okay - tested each power valve as advised and one is sorta tinkling when i shake it. Does this mean i just need to replace the single valve? Would that explain the lower volume and buzzing? Davie[/quote] Find a techie and have the valves tested ona proper valve tester. Quite often a valve will still work (ish) even when its gone right out of spec. Sometimes they go microphonic but work within specs and sometimes they go broke and microphonic. Also have any new valves tested before you use them, I lost a couple of hours looking for a fault in an amp and it turned out to be a brand new valve that was shorted. Buzzing similar to earth hum does sound like a duff valve, possibly one of the pre amp, drivers or buffers. Good luck cheers Just

[quote name='stevekendal' post='925974' date='Aug 15 2010, 11:07 PM']No they're not dear, but they are soldered directly to the board and there's about 20 of them! Which one might cause the OL light to come on? Fraid I'm too far from Bristol (Kendal)[/quote] Ok then its time to start going through the schematic and looking at what components are associated with the overload led. Sometimes it can be cut and try with fault finding although if you have or have access to an oscilloscope and a signal generator you can chase the signal through the circuit and see where its going wrong. If your really stuck and it seems like your going to have to take it to a techie then dont do anything to it as this can make for a hard time for the repair man. ie not knowing if he's looking for a fault or if he's trying to fix what you've messed up. Good luck Cheers Just

[quote name='stevekendal' post='924870' date='Aug 14 2010, 01:50 PM']Ok, It atarted off being intermittent and now there is no signal getting through at all. If the gain controls are backed off, a loud squeal comes through. The input overload light is on all the time even with nothing plugged in. Steve. Ps, I have the circuit diagram, but it wont post on here, just e mails ok.[/quote] Hi, it sounds like you've got a chip gone dud on you somewhere in the pre amp circuit. Not sure which ones the laney has but they dont cost much and if your lucky they'll be on chip sockets so should be easy to swap out. Dont forget to note which way round they're fitted. If you're in or near Bristol PM me, I run an amp repair business. Good luck cheers Just

hi, Tube amp doctor do tranformers for just about all the most popular makes of valve amps. But as mentioned they're not cheap. If you wanted to do a copy of a mesa 400 or an SVT you'd be looking at about £200 each (mains and output) and even if you only wanted to do bassman copy they're still knocking for about £100 each. I took the ones for my amp (still in progress) from an old peavey along with the chassis. I think we only do these things for the sheer hell of it. It's not cheap in time or money but you can get something that you could'nt buy. will be interested to see how your mates turns out. Cheers Just

[quote name='RockfordStone' post='893239' date='Jul 12 2010, 10:21 PM']hey guys, really hoping you can help me the jack on my ibanez edb605 appears to have broken. it looks like one of the contacts in the socket has snapped and therefore it isn't making a proper connection when i put the lead in. i need to find a replacement, but i don't really know where to find one from. im wondering if one of you tech savvy bass geniuses would be able to help me out and point me in the right direction towards one. i believe it is a stereo , and the bass is active if its any help. ive posted some pictures, ive looked around and i can't seem to find one that looks the same :S cheers in advance[/quote] That jack looks like the ones Peavey use in alot of their amps. Find a peavey dealer and order it through them, they're pretty good for getting parts off. Cheers Just

Hi, I repair alot of amps that have this soldering problem and have noticed it being quite common on a lot of newer amps and equipment that use lead free solder. It seems to be much more brittle and from having done production work with it it is a lot more difficult to make the solder in a joint flow due to the temperature required. I usually reflow these with leaded solder. As mentioned its quite common on larger components and any that are under physical load, inparticular input, output, FX and mains sockets. DONT FORGET TO UNPLUG IT WHEN YOU TAKE IT TO BITS. I know this by experience. Good luck finding the fault. If your not sure what your doing go to a proper tech. Cheers Just

+1 on the De-oxit..best stuff I've ever used on guitars, amps and anything else. Well worth the extra money. Peavey Funk Out is also very good as it contains the same stuff. Cheers Just

Hi folks I'm looking for rotary switch as an alternative to a three way telecaster/stratocaster type switch. Can anyone recomend anything. Its for a diy stingray 5 project. Any sggestions welcome on makes and suppliers gratefully recieved. Cheers Just

[quote name='gilmour' post='886876' date='Jul 5 2010, 11:43 PM'] I'm quite lucky in that our guitar player is happy to just be a wah monkey al night, as long as he gets one solo. These are mostly going to be used for PA - although I'll definitely try them on bass, I couldn't resist it before... It was waaaay tooooooo much.[/quote] Looks mighty fine. Slight change of subject but while we're on the subject of BFM cabs what happened to the omni 10's? The design is'nt on the BFM website anymore. Anyone got any idea's? Good luck with the project, I still wanna do my own omni 15.....when I get time. Cheers Just

[quote name='L1zz1e' post='881709' date='Jun 30 2010, 10:48 AM']Ive got a bit of a microphonic issue.. I think my pots are causing the problem. Is this something one can fix or is it better to replace them?[/quote] Hi it could be the capacitor on the tone pot-I had the same problem on my Tokai Jazz. Open up the control cavity and plug the bass in to the amp at a resonable volume then tap the capacitor with the end of a biro or something similar and listen for the tapping noise coming out of the speaker. If it goes ping ping or similar then its probably the cap. If so get it replaced. If the pots are crackly get some deox-it(expensive) or Peavey funk out(cheaper) and spray them out. Maplins switch cleaner is a solvent and could damage the track in the pot. It also disolves the grease in there and makes the pots go all loose feeling. If you getting squeeling at high volume especially if using distortion or overdrive you could have microphonic pickups. Good luck cheers Just

Hi all, am I allowed to put my own details on here as an amp tech? I'm in Bristol and work out of a music shop. Was'nt sure i I'd be breaking any site rules by kinda free advertising(me and the shop).If anyone can advise me let me know and I'll put up what info I can. Cheers Just

Sorry but I'm after the actual circuit diagram. Thanks for the link it may still be usefull as its something of a complicated beast to fault find. Thanks anyway I'm going to have a go with loud technologies and see how it goes. Cheers Just

Hi all, as the title suggests I'm after a schematic for an Ampeg svt4. Have had a look about the web but nothing seems to spring up immediately. Does anyone know of a good link or even have it to hand? Any info grestly appreciated Cheers Just

Try it with another speaker and also check the connections, you may have dirt/corrosion in the output jack. If no luck try heron music, they'got a good tech and are a peavey dealer.

[quote name='farmer61' post='549121' date='Jul 23 2009, 04:26 PM']Mine too, not every 5 minutes though. Reckon it's joint problems on the inards when it warms up. The heat expands all the joints probaly causing a break in the circuitry. As someone earlier said, take it to a tech who can follow circuit diagrams. My amp is a Trace Elliot for reference.[/quote] Hi I repaired a trace recently which had this problem. It was the cooling fan. The fan should run continuously. If the fan is not running its either the fan is faulty, or the cicuit which drives the fan and controls its speed as the amp gets hotter. Your probably finding it cuts out when its being pushed at proper gig level rather than playing quietly at home. Hope this of some use Cheers Just

Hi all, Ive been given a Trace gp12 smx 4x10 to fix which is cutting out after being played at band volume. My question is; should the fan run continously or is it "inteligent"? I'm sure there's plenty out there with one so any advice on this is welcome. Also if anyone has a schematic that would be a big bonus. Cheers Just

Hi I see your point entirley regarding build quality and robustness. If your good at building stuff try the Torres website. If you ask nicely they will do a higher power (200w) version of the thunder bass. I'm currently canibalising an old peavey valve head for its transformers and chassis to build a 120w head and Barry at torres was more than helpfull in aggreing to supply the rest of the bits including the all important assembly manual and diagrams. Dont forget though it wont neccesarily be cheaper to build your own but you do get full control of the QA dept. Good luck Cheers Just

I've had two ashdowns in to me for repair recently and would'nt have one for a gift. I got no reply from them in request for a guitar amp schematic and the build quality of the 1x10 bass combo was appalling not to mention the sound. Surely if they market themselves as an engineering company they should at least screw things together properly, and not use 10mm self tap screws to hold a speaker in place with. No wonder it was making a farty noise. Utter crap. There rant over. Cheers Just

Ah yes the Torres site is good indeed. I enquired a while ago about the thunder bass head and for not too much more they'll do it as a 200 watter. In the meantime though I bought a book instead- Inside tube amps. Well worth a read if your into building or tinkering with amps. Nice job on the bassman by the way. Cheers Just