1960(?) Epiphone ea35t suggestions

[Roony Tune]

Hey I'm new here and thnx in advance for patience..
After hours of research I've discovered Epiphone produced the Devon Tremelo using el84's with identical posted specs (inside)as Gibson's ga-8t that uses 6m8m. Question: any suggestions for upgrading ot with some caps for more bottom/mid?
Thanks
-R

[Roony Tune]

Forgot to mention I believe this to be a 1960 ea35t with (1)-2ax7/5y3/(2)6bq5's

[tubenit]

That was the first tube amp I ever owned.  Reportedly, the one I had belonged to a guy in a garage band with a harmonica player that later became Willy Nelson's harmonica player.  Don't know if that's true or not?

On V1b plate,  I would change the .0005 cap (essentially a 500p cap) to .01 and see if that helps get the tone you want?

The other change for that amp is a different speaker.  The stock speaker on my amp was very trebly/tinny sounding.

So, I'd probably change that one cap and get a better speaker.

Here is a poor quality picture of the one I had.  I (foolishly) threw away the original cab and built one out of oak for it.  The guitar was a cheapo Fender Bullit where I threw away the body and made one out of maple. 

With respect, Tubenit

[Roony Tune]

Thanks! I've already put a Celestion "typeA" in it and it helps a lot. Someone has already brought this back to life with the three-in-one can using three separate caps and a few other things. I'm new with this site and just now learning how to navigate/post, and also using my smart phone which is challenging so I'll wait till I get back home with laptop

[PRR]

Welcome.

> that uses 6m8m

?? 6BM8?

> (1)-2ax7/5y3/(2)6bq5's

It would be hard to do guitar amp, push-pull, with trem, in one 12AX7. You really want two gain stages, a phase splitter, and a trem oscillator. As a 12AX7 has two units, four units seems to be two bottles.

{EDIT- you followed-up before I could post this} I sure would try a known-good speaker. Epiphone was a bargain brand and the factory speaker may not have been the best. (If it has been replaced, who knows what got in there?)

[Roony Tune]

Sorry 'bout that...attempting to up-load a pic from my phone without success...
Anyhow, yes Gibson used 6bm8's (typing on a phone haha) but I believe these are parallel single ended, not push pull?
The tremolo on this particular ea35t I think is running off half an el84... This is the tweed style with top mounted controls.

[shooter]

here's a link to a 35T schematic doug has;
http://el34world.com/charts/Schematics/files/epiphone/EPIPHONE_EA-35T.pdf
This version is PP vs PSE.   
I built a GA-8T using the PSE Gibson had, and *pasted* a Ricktone Trem circuit but I injected it at V1b cathode, worked ok, little anemic.

The schematic I linked to looks like if you just clean n polish it and find the right speaker as has been suggested, you're about as good as it gets

[Roony Tune]

Thanks, Shooter
That schematic is for the crestline, but the amp I have has the single 12ax7 with 5y3 and two 6bq5's and the tube layout sheet inside is identical to the other schematic Doug has for the one particular Gibson ga-8t (discoverer)...
Unique I guess because I haven't found any other references online but I understand Epiphone (like Gibson) changed schematics/designs often after 1960.
I'll try an get pictures up which will be helpful, but I'm certain this is parallel single ended. Curious, on your ga8t mod what do you mean by anemic; the tremolo or overall sound?
Thanks for helping,

[Roony Tune]

Forgot to reiterate:
The schematic inside this ea35t is identical to the ga8t discoverer schematic Doug has posted. Identical (except) power tubes...
Gibson: (1)12ax7/(2)6BM8/5y3
Epi.         "       " /(2)6BQ5/"  ""

Thanks again everybody

[Roony Tune]

Well, once again MUCH gratitude for all your replies. The most important part I left out from the beginning of my quest here is that this amp is up and running and the tremolo has its original wooden foot switch. It sounds amazing at 3/4 with a hint of breakup pushing the 12" Celestion Type "A", but per my quest I'll take any and all advice for fattening it up some before I buy parts.  It's my first vintage Epiphone and I've invested a fair amount of time figuring what year it was made without having a speaker date or digging into it, and so far it's still a mystery. The only other "tweed style" models with tremolo I've seen came with 10" speakers and/or were push pull.
I'll keep you posted with pics soon, thanks again.

[sluckey]

The schematic inside this ea35t is identical to the ga8t discoverer schematic Doug has posted. Identical (except) power tubes...
Gibson: (1)12ax7/(2)6BM8/5y3
Epi.         "       " /(2)6BQ5/"  ""

Would you take a picture of your actual schematic and post it here? I find it hard to believe that one 12AX7 and two 6BQ5s make an amp with tremolo. The schematics can't be identical if the Epiphone has two 6BQ5s.

[Roony Tune]

once I get my laptop to a wifi I most certainly will. I understand your bewilderment because I was just as amazed when I discovered this myself. By the way, no offense taken on doubting my word.

[sluckey]

...By the way, no offense taken on doubting my word.

Good. My post was not meant to question your word. But let me explain my reason for wanting to see the schematic.

The Gibson has one 12ax7 and two 6bm8s. That makes a total of four triodes and two power pentodes. That's plenty of triodes to handle preamp gain, post preamp gain, phase inverter, tremolo, and power amp.

But if you only have one 12ax7 and two 6bq5s, then you only have two triodes and two power pentodes. I just don't understand how that's enough tubes to do all that. If I could see the actual schematic that would help me to understand.

You did say "...I'm certain this is parallel single ended." If so, the schematics cannot be identical.

And you also said "The tremolo on this particular ea35t I think is running off half an el84... " But an el84 is not a dual tube. It only has a single power pentode.

[Roony Tune]

6BM8s!
I'm sorry if I wasted your time. I'm new, but eager to learn as much as possible every day.
So does this mean this amp is Gibsonette? With trem? I see the regular Devon ran with both 6v6 and 6BM8  but Gibson shipped a model just like this.
Can I still get a slightly larger output transformer and compensate a couple fatter caps to bring out a little more bottom?
Thanks again for your patience, I'll try an pay better attention
-R

[Roony Tune]

I can't seem to get pics up from my iPhone se

[Roony Tune]

I'm truly embarrassed because I've been away from it and have been researching single ended parallel el84s. Thanks for straightening me out.

[sluckey]

6BM8s!

That makes all the difference in the world. Of course they can be identical schematics. 

I can't seem to get pics up from my iPhone se

There is a file size (bytes) limit on the forum. Maximum size for a single file is 1024KB. You have two choices. Make the file size less than 1024 with your IPhone or other software, or upload your file somewhere else on the net and just post a link to it.

[Roony Tune]

Thanks for that, now I'm understanding that the older Gibson ga-8 runs pse but the Epiphone ea35t runs 6BM8 push pull. (I was like, "wow...an se dual el84!"...brain dead.
These 6BM8s sound incredible with the 12" woofer when pushed hard. A little tin at lower volume.
I think I'll run with Tubenit's heads up on the 500 to a .01 on the V1b plate. I'd read where someone else used a .022uf (I think) and a couple larger feeding power stage grid.
The person who had gotten this amp running I've never met, but there's zero hum and its quiet as a new amp should be. The tremolo is a little fast outta the gate, though. I pretty much don't dial speed past 2/3.
Thanks again info and schooling.

[sluckey]

Here are the two schematics from Hoffman's Schematic Library (available thru the link at the bottom of this page) for you to compare...

     http://el34world.com/charts/Schematics/files/gibson/Gibson_GA-8T.pdf
     
     http://el34world.com/charts/Schematics/files/epiphone/EPIPHONE_EA-35T.pdf

According to these schematics... They are both push pull amps. Neither is parallel single ended. The Epi uses two 6EU8s and two 6BQ5s (same as EL84) and a 6CA4 rectifier (same as EZ81). The Gibson uses one 12AX7 and two 6BM8s and a 5Y3 rectifier.

The circuits are very similar but just the fact that they use different tubes means they are not identical. I'd still like to see a high rez pic of the actual schematic inside your amp. Gibson was famous for making undocumented changes in their amps, so it's possible that these two amps are examples of that. Maybe your actual schematic could help clear up some of this fog.

[Roony Tune]

Thanks, Slucky
I'll have to use my laptop for uploading pics, but the schematic in my Epi matches schematic in the link you shared for the Gibson ga8t (for your knowledge till I get it pic posted). Everything matches to a "T"
Ill learn hear better with my laptop how to include links etc, so again thnkx for patience working with me; I was born a month early...been late ever since...

[kagliostro]

To manage large images, upload it to an host image service

(I use Imgur that is free and didn't delete images after a certain time - http://imgur.com/)

and when you have uploaded the image just copy the link from the host and paste it in your post

using the image tag

this is an example



Ciao


Franco

[Roony Tune]

Thank you for that...albeit my lack for smartphone prowess!
After more research last evening I'd discovered a thread at "Trinity Amps" after googling 1960 Epiphone Devon amp. The pics on thread are the exact same amp I have here. I'm beginning to think I should abandon this thread and leave the amp well enough alone as it has already had energy invested in getting it running; although the tremolo is deffinately running a little too fast. It's working (trem) but not much dynamics for exploring.
I've discovered an old thread here on 6BM8 amps and I'm now completely smitten with this entire site.
I also discovered the Goodsell Unibox 10 while cruising around online and believe my best bet would be to just try and build an amp using these 6BM8s...what a cool crunch!