Tube Amp Archive

That fixed it . I am now measuring 6.6 vac on both of the 6l6 filaments and still 13.4 on the 12au7 filaments . Nice ! Thanks Mr . Manning . It's still running and the tubes seem fine . Of course this is nothing but the heater circuit hooked up . What are the chances of that voltage coming down ? An...

No it is not . I grounded it to the chassis and forgot that I removed the K resister when stripping the chassis . Good call . I'm out to do that right now .

So I wired up the other noval sockets . Installed two 6l6 and two 12au7 tubes . Theses are my readings on the filaments . I get 13.4 vac on each 12au7 tube . The next tube in line (6l6) is reading 6.0 volts and the last tube (6l6) is reading 7.2 volts . I measured 121.3 volts coming in on the primar...

I seem to remember having two of these chassis . I think I left the other one as it was wired and replaced only the original pre amp circuit with a deluxe style pre . If my memory is correct , and if indeed it was the same chassis, it seemed to work well . Can't remember what happened to it though ....

I measure 13.4 volts unloaded on the heater tap martin manning . Stevem , I suspected there might be a problem without all the extra 12au7 tubes in the heater circuit and so I asked the question . I have not built a DC heater circuit as of yet . Would this be a possibility with this heater setup ? I...

I dug an old Conn organ amp chassis out of my garage the other day . Thinking about building an all octal Fenderish circuit like a Pro . This is how the heaters are wired on the organ chassis as far as I can tell . The PT fed two 6l6gc tubes and two 12ax7 tubes plus about 40 or more 12au7 tubes . Pl...

Here is what I have . It's in three parts .

Structo , I bought this unit with about 4 other amplifiers . I gutted one that was an old Bogen mono unit for the trannies and the others I sold on an auction site . I had a look at all of the units and this one impressed me the most due to the neatness . To me it looked like the easiest one to work...

I found a schematic on someone's flickr account . I was also able to place an order for all but one of the filter and bypass caps . I am still looking for the 150@300 capacitor . I was able to keep the values real close to originals . I need to find a few terminal strips now . I measured the resiste...

I think that's a good idea using terminal strips . How about the Pyramid signal caps ? Is there a way to test them for leakage ? If they are good is an upgrade really going to make that much of a difference in the sound ? Someone mentioned replacing the little disc caps as well . What is the advanta...

I went ahead and opened it up . A quick test with the multimeter and the cathode resisters test 135 and 149 ohms . The resister on the left is the one that drifted up . They are both marked 135R . So I need to replace at least one but will replace both when I replace those 100mfd @ 25 vdc bypass cap...

Thanks Phil . I don't think there will be a next guy . Just the thought of going on the mouser site is giving me an anxiety attack . I will probably use one of your other suggestions . I went through the amp with a multimeter and the resisters all seemed to be pretty close but that was a while back ...

On top of the chassis are three cans . The one wrapped in cardboard is 200mfd@25vdc . The one in the middle is also 200mfd@250vdc . This is the voltage doubler circuit I believe . The last can is 20mfd@350vdc and 150mfd@300vdc . The can near the preamp tubes reads 60/60mfd@250vdc . I need to locate ...

I'm in need of a little advice on recapping this little amp . I fired it up and used it for a few hours and it sounds great . Did a little clean up of the pots and switches so no "crackle" or other weird noises . It seems to be working fine (although the power tranny seemed to get hot) but I want to...

I have had a few of those amps . Most of the time there are the blue molded caps in the PI section . Probably about six of them . If it has the leslie that usually has a nice little 8" jensen . There is a little preamp section housed in a nice little chassis suitable for a champ style build . I thin...