The Amp Garage

Shorting the meter probes together prior to measuring any resistance is a basic sanity check.

For better reverb range of control, try a log / audio taper reverb control. Stock is linear. Regarding the hiss, are you sure the inputs are wired up properly? New builders seem to have problems getting that right. Another new builder thing seems to be comparing the noise / hiss of their new non mas...

The 47k resistors aren’t dropping any gain.

Have you checked for oscillation?

… My meter for some reason didn’t like measuring the primary and was unable to give a reading, it kept going from nothing it O/C. I found I was able to get a reading by turning it to diode mode and then resistance. The diode mode readings were different of course but led me to a similar conclusion ...

I know the OT they used has 6K and 8K primarys. ( not sur which they used ) What was the original JTM45 Ot primaty and, would the fact that : " Trinity has the same turns ratio but is wound in a different pattern to accommodate extra taps " make that amp sound significatly different ? My understand...

What I was looking for was the blue to brown resistance, and the blue/white to brown/white resistance. Are you able to check the primary to secondary voltage ratios? eg if a measured low V AC is applied to the 4ohm secondary, what V AC is produced across blue to brown, and blue/white to brown/white?...

Do the OTs actually present different impedances to the EL34 and 6L6 anodes, as per the patent and marketing? I recall reading that the extra OT primary wires were just for show, both anodes each side were fed from the same point. It might make a difference because if the EL34 really were working in...

The cathode bias resistor on V3 LTP should be 470R, whereas the value that seems to have been fitted looks like 470k.
The effect that would have aligns with the reported symptoms.

Well done, kudos on your ‘can do’ approach, I’ve been meaning to give that a try for a while (on an AC30), so thanks for reporting back!
Did you insert the TB between the channel volume control and the phase splitter input?
Photos?

Dealing with the public means occasionally having to handle / negotiate with people that behave like that. It’s nice to help nice people to get their amp working again and get paid for it, I guess this is the flipside. In future, if the customer can’t pay upfront but you don’t want their gear clutte...

It’s also worth noting the a resistor’s voltage rating can be important. Consider transient and dynamic conditions of each application before dismissing it as not being a concern, eg due to a low voltage across a resistor whilst idling. Also worth pointing out is that this is in regard of the leg to...

It would be possible, it’s a similar scenario to Fender’s 6G series, eg https://el34world.com/charts/Schematics ... _schem.pdf
But the design and layout will probably need amending to keep things stable and usable.

A photo clearly showing the component that the wires connect to would be beneficial. Are there definitely only 2 wires from the speaker assembly? Are any of the components magnetic? I get the impression that it’s not the standard magnet / polepiece / voicecoil / former / cone design. Maybe more akin...

Would I use the same Screen and Input Grid Resistors from the 6L6 when switching to KT66? The amp I have uses 470R for the Screens and 2.2K at G1.. hardly, since a real kt66 draws more screen current than a 6L6 … I never even seen a real MOV KT66, nevermind tested an amp with them to see how they p...