Centralab pot codes

[galaxiex]

I'm working on a Traynor Guitar Mate III that seems to be from 1969-1973 era.

I'd like to pin it down a little closer...

On the pots...

It has Centralab very clearly marked on the front bushing, but the codes on the back confuse me.

Did some googling to no avail...

On back of the vol pot is...    4482  1MEG-A  *then* BD7Q-7  OR   8070-7

The 1MEG-A is easy, the rest...?

The BD7Q or 8070 is hard to read, I'm guessing it's 8070.

The Centralab manufacturer number should be 134 but it's not there...?

Thanks for any help.

Edit; hmmm   8070   8th week of 1970? but why the dash 7?

[g1]

The first 3 digits of the amp's serial number should be year and month (for Traynor).
As you say, it will be either 60's or 70's.
For example, 907xxxx would be July of 69.  210xxxx would be Oct. of 72.

[galaxiex]

Serial # 22244

Maybe 22nd week of 72?

[Enzo]

So how about date codes on larger caps, the transformers, the speakers, other controls, larger resistors, etc.?

[g1]

Serial # 22244

Maybe 22nd week of 72?

It should be a 7 digit serial number.  Maybe there is a "1" in there somewhere?
Otherwise, please post a pic of the ser.#.
Some real old ones had 4 digit serial, but they went from 4 digit to 7 digit, so 5 digit is not a valid traynor number.

[galaxiex]

I took the vol pot codes cuz some of the other pots are obvious replacements.
The remaining original pots have the numbers obscured by solder.

Here's pics of some of the other hardware/parts.

Serial # pics... the plate looks original and not altered in any way.

...
Some real old ones had 4 digit serial, but they went from 4 digit to 7 digit, so 5 digit is not a valid traynor number.

The P/T sure is massive for a 22 watt amp.

Traynor wasn't shy about using beefy parts.

[galaxiex]

Pics of the original speaker.

I swapped it out for a Celestion G12H 30 watt

[Enzo]

At least the speaker has a clear 1972 date code.  Eminence.

Traynor was always good sturdy stuff.

[galaxiex]

At least the speaker has a clear 1972 date code.  Eminence.

Traynor was always good sturdy stuff.

Thanks Enzo,

Hmmm, Eminence, and for some reason I always thought it was a Marsland or RSC.
I never looked up the EIA code for Eminence before but there it is... 67

I used to have a mid/late 70's Traynor YGL-3 Mark III Combo 2X12's  "Twin Killer".

Wow that thing was heavy!
Incredibly Loud!
Just all around massive.
Built like a tank.
Good thing it had casters.

Kinda wish I still had it.... but it was waaaay too much amp for what I needed.

I got it cheap ($300.00 CAD) compared to what they want for them now.

It needed a vol pot and one of the output tubes was shorting.
Fixed that and changed the main filter caps.
Sold it for $600.00 a year or 2 after I got it. Oh well...

Even this Guitar Mate is heavier than my 78 Silverface Deluxe Reverb.

Edit;
I found a PDF that decodes the Mallory caps.
They date to Feb 1970,
of course they may have been sitting in a parts bin for some time before being used.

DE = Mallory
B = Feb
0 = Year, in this case probably 1970.

[g1]

Some real old ones had 4 digit serial, but they went from 4 digit to 7 digit, so 5 digit is not a valid traynor number.

Except when it is a valid Traynor serial number. 
So the info I had about the earlier than 7 digit numbers is wrong.  I've contacted Yorkville to see if they have any insight about the 5 digit ser.#'s and what the year might be.  Hopefully they will have the definitive info.

You are right about these coming with the Marsland speaker, I think someone swapped it out in this amp.  The original would have had the Traynor part # 7372 on it somewhere.  That 12EAGA8C number seems to be from vintage organs, possibly Wurlitzer.

[galaxiex]

Some real old ones had 4 digit serial, but they went from 4 digit to 7 digit, so 5 digit is not a valid traynor number.

Except when it is a valid Traynor serial number. 
So the info I had about the earlier than 7 digit numbers is wrong.  I've contacted Yorkville to see if they have any insight about the 5 digit ser.#'s and what the year might be.  Hopefully they will have the definitive info.

You are right about these coming with the Marsland speaker, I think someone swapped it out in this amp.  The original would have had the Traynor part # 7372 on it somewhere.  That 12EAGA8C number seems to be from vintage organs, possibly Wurlitzer.

Thanks g1 

I'm not surprised that the speaker may have been swapped.
I bought this amp a long time ago (mid 1990's) but I recall the guy selling it said it was a Marsland...
... "cuz you can tell by the silver dust cap"...

Of course many speakers came with that feature, so I think he knew the speaker had been swapped,
He made the point that it was "original".
Anyway, no big deal.

Of some slight concern is this amp has had some extensive circuit mods.

Extra preamp tube added, triode/pentode switch, master volume,
Fenderish tone stack with mid control replacing one of the input jacks.
Too bad about the hole in the chassis for the extra tube and the tri/pent switch... oh well...

I am trying to wire it up as per the original schem that is pasted inside on the chassis cover.
Not sure if Traynor updated the schems when there were revisions...
The schem is dated 1969 but some of the original looking part values don't match the schem.
Also kinda tough to find a chassis circuit layout.
Found some pics online but they are not the best quality.

Along the way I will make some "normal" mods as recommended by Kevin O Conner in his book TUT3.
Easily reversible stuff like adding screen resistors and adjustable bias.
I may use the original ground switch to make the neg feedback switchable.
I did that on my 3 Silverface Fender amps, Vibro Champ, Princeton Reverb, and Deluxe Reverb.
I really like the different sound of switching out the neg feedback.

The collectible value of this amp is already compromised but there are lots of them around.
Traynor/Yorkville has reissued the early version and done a really nice job of it.

Edit;
Sorry, this is turning into a discussion about a tube amp... 
Mods, please move to tubes section if you like.

[g1]

Yorkville says their records show that serial # from April of 1970.

If it's got that much in the way of mods, I wouldn't trust any parts that look original to necessarily be original.  You can compare to the pics in link below.
There are 2 very simple common mods that are quite popular.  First, removing the bright cap across the volume control.  Second, removing the "presence" cap in the feedback loop/PI circuit.  It's the .1uF across the 4K7 (R13 on re-iss schem. attached).
Once you get back to stock, try them out and see if you like the results.
The attached service manual also has a board layout that should be close to the original.
This link has some good pics of the layout for both the re-iss and original:
https://www.tapatalk.com/groups/ampworkshop/new-traynor-handwired-amp-t4291.html#.UlGcAtKdFvA

[galaxiex]

g1, thanks very much for that.

You got an "in" with Traynor? 
Very cool to know the production date of this amp.
April 70 coincides with the Mallory cap date of Feb 70.

Thanks for the link, I came across that page in my own search.
It helps but some stuff is hard to make out and differs from parts of my circuit that I think are original.
I agree that I probably can't trust a lot of it... but *some* of it really doesn't look touched at all.

The re-issue layout I found too.
It's "close" but differs enough that it's only limited help.

That said, it probably doesn't matter too much,
as there is no way I can ever put this back to exactly like original.

The bright cap and presence cap I knew about from reading other posts here about this amp.
I'll try it both ways and see what I like.

I also found these 2 schematics that are helpful.
Interesting mods...

[g1]

Somebody did a nice job on those schematics!
I used to work on a lot of Yorkville stuff so I have a few contacts with the corp.
If you want to post some pics of the guts we can speculate about the parts that look original but don't match the schem.

[Enzo]

Our band used to play in Ontario a lot, they seemed to like us there.  A gig in Chatham I liked.

Canada had a huge import duty on guitar amps and PAs. like 50%.  SO Canadian bands used Traynor a lot, as it was home grown.  I saw a lot of Traynor over there. I liked Traynor.  Roomy inside, and built like a tank.

Traynor the company was always supportive.  Always ready with schematics or parts.  And I always felt you got a good deal of equipment for your dollar with them.  Can't go wrong with Traynor.  If you will, they were like the Peavey of Canada.