Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: capmando on February 06, 2018, 02:39:43 pm
-
Repairing a Traynor YGL- 3/3A combo twin 1976. Mouse eaten wires a dozen.
started replacing wires and noticed on original schematic heater wires drawn as parallel like they should be.
Wiring between 4 power tubes 6CA7, is different than schematic. Pin 2 wired to pin 7 on two of the first power amp tubes.
then tubes 3 and 4 in parallel. This seems weird or is it a 1970s way of reducing hum?
Has anyone ran into this before?, any guesses
or is this a hornswaggel mark 3 reconfabulation that a newbutter like me has never seen.
Wiring then recap with electros, to note: white wire is new not hooked up yet, to cap and resistor, I stopped work
when I saw this!
thanks in advance
-
Pin 2 and 7 are totally interchangeable. No polarity. No reason to track one green from the other green. Hum is a non-issue in the power stage. All your heaters are wired parallel.
ALL: is there a source of good "spaghetti" in an appropriate size? That would cut the number of joints capmando has to break and re-do in half. And while I am not a big wire-sniffer, I would tend to want to retain most of Pete's cloth just for the 1970s flavor and mojo-aging.
-
Thanks for replying so soon PRR. Say hello to Maine for me beautiful place, used to spend time in Bar Hawbor.
So If I think of this, your saying there is no polarity because its AC, and because the heater source transformer winding is floating, I get ya.
I am looking at Dougs heater wiring diagram and the wires are parallel same tube pin number to same pin. Is it just ascetics or is there phase to consider with different powertube setups?.
I am using 20Awg 600V rated wires for the moment, may need to change power tube sockets. The original wires are
cloth covered PVC wires, that must have tasted good to that mouse who chewed them.
Well seems like good news to me, on to recapping. I wonder what how the Atoms vrs Nichi for a 25 uf 25v sound ?And is a 50 volt going to sound worse than a 25 V
Also the amp has a circuit breaker at 4.55 amps hold rating. Wanted to change it for a 4 Amp fuse.
Anyone ever done that, better to keep circuit breaker? Also bought a Variac and light bulbs. A dim idea.... Ha ha
-
Is it just ascetics
Yup n simplicity, phasing has been debunked :laugh:
50 volt going to sound worse than a 25 V
I don't believe there is any + or - to sound, bigger Uf's seem to help keep bass tighter, voltage just keeps it from exploding.
I'd leave the breaker, feel better, add a fuse to protect it :icon_biggrin:
-
> looking at Dougs heater wiring diagram .... Is it just ascetics
Drawing it "in phase" avoids time-sink questions from readers of other gurus who say "do it this way".
(Also in computer drawing, it may be simpler to draw one socket and then paste-paste-paste, and then they naturally all come out the same.)
At Traynor they knew it didn't matter. They cut two wires off the same roll, stripped, twisted, and wired the socket. Is that 3 twists or 3-1/2 twists? Who cares?
-
I feel more at ease about the heater wiring, continuing ahead with the project. Thanks for that.
10 caps later, Some Caps are 2 times or more original value out of circuit!
Working on this fiberboard and bushing circuit board, I am beginning to see the ease and quickness of Mr Hoffman's turret boards.
Interesting Idea adding a fuse to existing amp chassis breaker. Going to try it.
Is there a quick way to test an optoisolator part for a tremolo circuit without powering up?
I feel there is so much i don't know, and you guys have been really great with your time.
Thanks for answering my Questions.
-
Is there a quick way to test an optoisolator part for a tremolo circuit without powering up?
That opto is a neon bulb and LDR. No easy way to check without power.
-
Time to turn it on!. Thanks