Second #124

[67plexi]

Thanks to all this build is a 100% killer. I started out with JBL’s then EV’s then rewired my Marshall cab to
4 ohm’s. 1970 twin output transformer and choke. Loud as hell. I’m happy.

[Tonegeek]

Looks authentic. Glad to hear it sounds killer. i am hoping to get the same thrill from my Twin (really '70 Dual Showman) conversion to #124

[mad_dog]

Nice looking build.

Is that chasis from the recent run

[CHIP]

Nice build, Did you decide against installing the FET input?

[dogears]

What value PI plates did you use?? Is that a 91K on the non inverting side?

[67plexi]

The gut shot is not of the finished amp it is stock #124 layout. The fet is installed. The only change is .0047uf On the rock-jazz switch. And the input on v-1 is 22k. The b+460v. Used a 3k instead of 2k2.
V1 triode
V1a plate, pin 6, 196v
V1a cathode, pin 8, 1.66v
V1b plate, pin 1, 194v
V1b cathode, pin 3, 1.63v
V2 triode
V2a plate, pin 6, 218v
V2a cathode, pin 8, 1.8v
V2b plate, pin 1, 216v
V2b cathode, pin 3, 1.82v
V3 triode
Input-side of plate, pin 6, 300v
Feedback-side of plate, pin 1, 299v
Bias voltage -47v
Fet drain voltage, 11v

[Structo]

Nice!
What kind of resistors did you use?

[Colossal]

Nice!
What kind of resistors did you use?

Tom, the brown plate resistors are IRC GS-3 metal films, probably the 3W 1% line. Very warm and natural sounding without excessive detail.

[talbany]

Steve
Congrats man.. Sweet build.. Enjoy the fruits and nice plate caps..

Tony

[David Root]

Don't you love that old iron?! What PT did you use?

[David Root]

double post.

[67plexi]

Got to love the Mallory TC filter caps. I set a sprague atom to show the larger size of the Mallory. The amp sustains for 13 sec. Blows me away.
Just scored a 1969 twin iron set for the next build. This #124 build scares
me, soon it will be woodsheading time on the guitar.

Thank's to all.

[M Fowler]

Yes those are some rather large caps, I can't find any of those old orange TVA caps in the right size oh well.

Good score on the Twin iron.

[Max]

I can't find any of those old orange TVA caps in the right size oh well.

AFAIK F+T build or at least can build exact replicas: http://www.ftcap.de/seiten/en/home/home.php

Cheers,

Max

[grtamp]

they seems little in dimension also!