The Amp Garage

Without knowing the bias condition and tube operating point any values mentioned for current would be a guess at best. Looking at the tube data sheets will give some a clue to the current. Multiply by two since you have two tubes.

So yes, measuring current will give the most accurate values.

John

kricke40, The math is the easy part, but first you need to know the current that will be seen through the resistor. V = I x R or 30 Volts / current = resistance needed. A pure guess that will probably get fairly close is to use the same value that you will for the power tube cathode resistor. Of cou...

If so what did you do about it? cheers Nick Nick, What you are speaking of is power scaling. KOC / London Power has released new super flexible DC power scaling kits that allow the use of nearly any control pot desired. I believe this kit would resolve any concerns that you may have. Or, wait 'till...

Firestorm, I did not have much induced noise due to imbalance, but my first power supply capacitance was huge, in the range of 200 uF as I originally built the amp for drop d tuning. I also used a number of small poly caps and a small amount of series resistance to help decouple and limit the diode ...

Andy, Nothing special was done. The amp was a silver face bassman chassis and xformers, with a new circuit card ala John Mcintyre's blues maker meets a jcm 800 with dual bias pots. 425 v on the plates. The only way I can descirbe it is "cream with the crunch". Try it, its fun.... and it is still dar...

Andy,

I have had great success with mixing individual 6v6 and 6L6 tubes. I think the imbalance actually adds dimension and warmth. Try and run 'em in triode mode too. Seems to loosen up "50" watt amps.

Just another color of the sonic palatte.

John

Gents, For those that have used the C-Rex, have you paired it with another type of speaker with success? I have heard that the Eminence RWB could be a good pairing. Looking for something with very tight / smooth bass with rolled off highs. It will be mostly used for high gain blues / rock. Love the ...

Thanks for the info Dan, really looks nice.

I've got a 4x10 bassman that I need to fill with speakers, one channel is a pi$$ed of fender and the other is plexi / bassman bassed and I'm looking for a 10" speaker with a greenback sound...

Thanks,

John

Hey Dan, looks great. Who did the name plate and what 10" speakers are you using in the cab?

Take care,

John

DerStever, I think you are making this more difficult than it is. As the Liverpool is designed the input cap to the PI is the DC blocking cap from the plate of the previous stage. The pre-PI master that you sketched would be more difficult to impliment than Kevin's modified bootstrapped master with ...

Eric, [/quote] Someone's peaking at my EXIF! You peeping-John! :) [/quote] Nope, no pixel peeping / exif looking, been a member over at dp review for years and recognized your handle. The internet is not a big as people think! :D I don't spend much time over there anymore, too many trolls, flamers, ...

Looks like you are getting good use out of the D300....

I still haven't tamed the beast yet....

Take care,

John

DerStever, Why don't you ask Kevin what he recommends? He is a good guy. You could also ask over at powerscaling.com, Kevin and others participate there. His TUT4 details an improved "bootstraped" MV that supposedly works very well, I have not tried it yet, but others say so. I have played with most...

Got to say Max, it all sounds really good.

Take care,

John

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