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[tubeswell]

Try a Fender roach and see. There will be ways of getting it working.

Or change the circuit to a vactrol trem - much simpler, works...

[tubeswell]

Here ya go - says the roach is a 'Model TM1 Factory Replacement Only. Patent Pending' as if that's any help. At an outside hunch, sticking a Fender roach...

[tubeswell]

Looking forward to this.

[tubeswell]

This is pretty much why noise cancellation won’t work in a room.

you’d need a ‘smart’ noise cancelling system that detected...

[tubeswell]

They won't affect B+. In the bias supply circuit, you have a total of 441.7 kOhm in series between HT and ground. That is a high impedance (almost effectively...

[tubeswell]

The bias supply voltage divider is split into 3 resistors. The 390k is seeing VAC (but nevertheless still forms part of the voltage divider.) The output of...

[tubeswell]

P56-57 in the attachment Darr4 Amp Signal Circuits.PDF...

[tubeswell]

And its clearly still wrong ...

The tail resistor should be grounded (or ground referenced to an NFB loop). Instead the LTP cathode is grounded...

[tubeswell]

Vg2 has as much effect on pentode or tetrode tube current as Vg1. If Vg2 is low enough, if can turn the tube off - even if your -Vg1 is 'normal' (But we know...

[tubeswell]

Yup ...

[tubeswell]

PI master grid and slave triode grid is still confused

...

[tubeswell]

Quote of the day!...

[tubeswell]

Just to add the picture, there is positive current and there is negative current. The latter is the opposite of the former. In the absence of other potentials,...

[tubeswell]

There's a mistake in the LTP. The cathode bias resistor is on the wrong side of the 2 x 1M grid leak resistors...

[tubeswell]

The dual PS rail for the bias comparator is powered from one of the windings on the filament PT. (The main filament connections to the output tube board are...

[tubeswell]

Scanty published information but the article by John Atwood starting at Page 12 of VTV Issue 15, attributes the 6V6GT as the 'prototype' of the 6973 and the...

[tubeswell]

Bit steep for a broken amp. YMMV...

[tubeswell]

so more like a 6CA7 or a KT77 then?...

[tubeswell]

Sucking air in and blowing it at the CPU will be best (assuming its cool air)

...

[tubeswell]

Good luck - I once disassembled and re-assembled a C30 13 times over 2 days trying to find a broken trace/jumper. I'll never get those 2 days of my life back...

[tubeswell]

If you want accuracy sheet metal drilling with a hand drill, you need to make a small guide indent by hammer-punching a guide-indent for the drill bit. A...