Best carbon comp supplies?

[azatplayer]

Got an AC10 twin on my bench, recap and a few minor repairs.Man the damn thing sounds fantastic! Really dig it. Gonna be hard giving it back!
Its from 63 according to the owner and has crappy old celestion G10L-35 speakers in it, but they sound bloody good. I did a quick vid last night for the owner to hear that it was workin..
I wanna build a version of it and wanna find some good carbon comps, have not really used them much so would like a heads up.
Cheers bigears!

http://www.youtube.com/watch?v=Xy8wffW-m-A[url]

[Phil_S]

Great tone. I feel bad for you. It's a keeper.

I've got a G10L-35 that I put in a Gibson GA17-RVT. I love the speaker. I think it depends on what you do with it. Many things have a time and place to shine.

[diagrammatiks]

you can still grab allen bradley's from surplus places and ebay.

that's your best bet for nos 1 and 2 watters.

partsconnexion has new production 1/2 watters from japan.

[mike9]

Nice tone - A '63 you say? Better measure every resistor in the thing to get the drift values for your build, or it probably won't sound the same - well maybe in 50 yrs it might.

[azatplayer]

Ahh yes i did measure a few resistors and the drift is massive. I intend to document the values before it gos home. They look really shabby too, some of the bands are near gone. It started out just a recap, but ended up the old re-al jacks were brittle and the spring contacts were moving around where the jacks had chipped away, one channel was staying open with the jack empty. So i had to replace them, using cliffs. Of course needed to relic the chrome bezels
In rewiring the jacks i realized they created an attenuation at the input deliberately crippling the amp to a supposed ten watts. That and smaller trannies and lower B+, kept it under the AC15, but essentially the same amp power wise. I rewired the jacks in a standard hi lo config and that opened the amp up immensely, also took away the crappy buzzy distortion the divider created.
It had 220k grids on each hi and lo input with a 1meg to ground. Thing is the inputs are in parallel with each other and the 1meg, with each grid resistor to ground when the jack is closed. So using either input gives you a divider of 220k-180k (220k*1meg/220k+1meg) giving a massive attenuation.
Also they ground one side of the cut control which gives much less cut control! So i lifted that as well as swapping lugs to make it more a tone control as thats what it is marked as.
Basic reversible stuff, which i think he will like.
The thing was wired wrong impedance too, luckily had not damaged the OT, running a 4ohm load from the 8ohm tap. Ended up sounding just great

[ToneMerc]

Ahh yes i did measure a few resistors and the drift is massive. I intend to document the values before it gos home. They look really shabby too, some of the bands are near gone.

Is there anyway to get a gut shot pic?I would like to see the type of resistors used.

TM

[azatplayer]

Sure thing took a few pics. Will throw em up tonite.

[ApexJr.]

azatplayer....

I'm a good supplier of carbon comps , american made
http://www.apexjr.com/images/APEXJRABCA ... STORS1.jpg
What wattage and values are you looking for, I have a large stock.

I've been told that the carbon comps after in circuit and heated up
come to there stated value.

Steve @ Apex Jr.

[rp]

I once owned one of these, a fawn one with the Elac speakers. Bought it pretty cheap sold it pretty cheap to pay rent. Mad good, one of the best amps amps I ever came across. Took off like a rocket, fast and had that instant swell and bloom of a 5E3 but Voxy. Big huge warm swirly sound that just wanted to run away on you. I drew a layout but forgot to blueprint it or make the schematic, this was when I knew even less than I know now and I might have drawn it wrong. Unfortunately my stuff is all boxed and packed now as I'd love to ask you some questions. It was the 3rd amp I cloned and the clone was a tone dud, sounded nothing like the original. I gutted it finally to make my lightning.

Please draw it out, dl the schematic - there are 2 out there IIRC, and see if you can note any differences. Mine had something like a 300 ohm resister btwn the rec and the choke, it looked original but it's not on the schematics. I really wish I had the voltage readings, so if yours sounds really good please do a voltage chart with the pre's too. I'm curious if your screens are the same or higher than the plates. Any chance you can get the Pz of the OT? I would love to figure out how to build a proper one.

Those G10-35Ls were used in original Matchlesses and well regarded for 2X EL84s. But the Elacs were amazing. Here's a pict of the Elacs.

[rp]

partsconnexion has new production 1/2 watters from japan.

Which ones are these?

[azatplayer]

Oky dokey, voltages.
PT secs, 290-0-290
EL84's plates 321V, screens 330V, cathode 10.5V/130R-50uf
EF86 plate 189V screen 40V cathode 1.32V
12ax7 PI plates 245/247 grids 48V each cathode 71V
ECF82 1-22V, 3-43V, 6-178V, 7-1.38V, 8-442mv, 9- (-17V)
im not sure what to make of the ecf82
The triode section is pin1=plate, pin8=cathode and pin 9 is grid
The pentode section is pin6=plate, pin7=cathode and pin3 is screen pin2 control grid
22V on the plate of the normal channel is odd, tho the schem shows 40V, so i guess its a weak tube or load R gone off spec.

The schem i have shows a 200R between the rec and the first filter node/choke
This amp does not have that.
What else is odd, both the schem and this am have the plates fed thru 100R resistors and the screens are fed direct from the plate feed. No screen R's, but they are there on the plates?
Anyways it seems like the amp is within spec give or take massive bits

[renshen1957]

you can still grab allen bradley's from surplus places and ebay.

that's your best bet for nos 1 and 2 watters.

partsconnexion has new production 1/2 watters from japan.

For those interested in a new production Carbon Comp, RCD (USA) produces a resistor that has the old school specs for coefficient of distortion similar to the AB and Stackpoles.

http://www.justradios.com/resistors.html

As to resistor drift, the old 10% tolerance used in the 1950's and 1960's would mean a 100k ohm resistor might have anything from a 91k to 110k resistor in the circuit (and the resistor code would be 100k). Usually the resistor drifts upwards, and humidity will effect the resistor, too.

Best Regards,

Steve.

[overtone]

Oky dokey, voltages...

Thank you I really appreciate the information. Still slowly collecting the old parts for one of these...
Not sure what the voltages on the ECF82 are telling us either. Is that a Brimar in that location?
Best, tony

[azatplayer]

Hey Tony. The ECF82 is unlabelled. I gave the owner back his amp yesterday, reluctantly.. My buddy teaches in the guys guitar shop, he said today all he coukd hear was this very toneful AC10 wafting thru the building! Of course that wasnt what he wanted while trying ti teach a student..
I gotta get some pics up of the innards soon, im just putting a bom together so i can order some parts. I really dig it

[azatplayer]

the amp i had does not have the xtra 200R between rec and choke, has the same secondaries so i guess the higher B+ from spec is due ti the missing 200R. Personally i reckon 330-335V is spot on for EL84's.