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The drain voltages on Q1 & Q2 should be about 8.4V because Q5-B and Q6-B should be Vcc - Vbe. Q5-C and Q6-C should be close to Vref. Make sure the 2SK193s are oriented correctly, Did you test them before installing? Make sure Q6 is 2N5087 and that it is making good contact in the socket...

What are your favorite new production EL84's? I'm replacing the output tubes in a Monoprice 15W amp that a friend gave me. One of the JJs in there has become gassy and lights up like the 4th of July.

We can do a quick cocktail napkin calculation to get into the ballpark. Maximum output swing is around 8Vp-p. Assuming a square wave, that works out to 4Vrms. There is a 560Ω series resistor (R15). Output power is Pout = 4^2/560 = 29mW delivered to R15. This is pretty much the worst case...

Depends on how much volume reduction you're looking for. Start with 220K and adjust from there.

This one's done. I tried some clipping options on the 1st stage just for S&G, but there were no improvements to be had.

Or move to Canada.

I had a little help from Claude.

When first the Wizard doth his pedal wire, And seats the germanium within its throne, He coaxeth forth a warm and singing choir, A tone so rich it chilleth to the bone. The bias set with most meticulous care, For leakage plagued by heat's relentless sway, Yet from this flaw doth bloom a sound...

It's amazing how LOUD a 5W amps gets when driving large speaker(s).

It bears a passing resemblance to the BB. But the EQ at every stage is different. The gain distribution is different. There is no resistor in series with the clipping diodes... Reference the schematic above. To lower the gain, first thing I would try is increasing R12. Change it to 3.3K for...

Looks like an EQD circuit.

Sorry, I meant R9, R11, R13, C5 & C6. I corrected my remarks above.

IC3 can be a TL072, then you can swap opamps between all 3 devices. Not recommending it, just saying it's possible.

I would not use the same device for the 1st and last stage because I want to keep input and output as far apart as possible. Many builders use a crazy order, but they're increasing the risk of oscillation.

One could make a case for putting buffers in both places. The Rat does not need a buffer before the TONE control because the impedance at the hard clippers is sufficiently low. That is not the case with the Rangemaster, which is why there was some noticeable signal loss. Not only that, but...

Holy Crap, Cooder! That is a bitchen tube collection you have there.

Adjust the Q2 trimpot for best tone when ATTACK is at max. ATTACK is not supposed to have a huge sweep. Personally, I like this circuit better without R9,R11, R13, C5 & C6.

This pedal has received some rave reviews in the Build Reports forum, so I had to breadboard it and see what it was all about. The circuit starts out simple, with the first two stages looking pretty similar to the BluesBreaker. After that, there is a whole lotta EQ. At low GAIN settings, all...

Go with the buffer. Use an emitter follower or opamp. Keep in mind that the example LPF came from the Rat, and in that circuit the LPF was followed by a buffer.

No, we would have to keep the coupling cap because we need the coupling cap to block DC. Also, we would need to either install a buffer before the LPF or increase the impedance of the LPF because otherwise the LPF would load the output of the Rangemaster. These examples are not stand-alone...