I spent about 10 years doing all my playing direct into a computer or a headphone amp.
Finally, I crawled out of the shell and started looking for an amp I could play at home at night and also in a studio/practice situation. I settle on the “Lil’ Lanilei” by Tris at Songworks. However, that took some eight weeks to build and I was getting antsy …
Then I read about Clapton using the Gibson Skylarks in the studio. A little research turned up some interesting points: They sound great, are damn cheap and have very simple circuits.
Turns out the real ‘Class A’ single ended Skylarks are not so cheap. This one went for $255 + 40 shipping and that is as cheap as I’ve seen one go in a long time. 400+ is the usual. They look like this :
After a couple of weeks on ebay, I found two 60′s Crestline GA-5′s (well, one GA-5T (Tremolo) and one GA-5). These are both Gibson ‘Skylark’ amps, but not likely the kind used by Clapton They each cost 200 with shipping and both arrived with significant hum. New, they looked like this :
As the GA-5 arrived first, I worked on it first. I removed the old speaker wire and added a longer run of real speaker wire, and I replaced the power filter capacitors. That amp rocks. Simply fantastic clean at low volumes and great 60′s crunch as you turn the (only) dial. The other ‘dial’ is the on off switch.
The other one still has a nasty hum.. I’ll start telling that story soon.
Dude, This is wild , I did a search on the word Paleoelectronics (as i have done periodically for the last few years ) and it finally has come up with you . Oddly enough I too used to do amp repair in Oakland Ca. Whats your name , Where are you located etc ? I started out learning to do amp repair on an Epiphone not unlike the one on your front page. Ive got a website that you might be interested in with a friend who builds amps out in Seattle. Oh yeah my name is Chris Murphy , Pleased to meet you
Ha.. awesome sculptures, very cool. Paleoelectronics came from a buddy of mine who thinks it’s hilarious that I’m futzing with tubes and stuff like that.
The Epiphone EA-50 is an exact copy of the GA-5 and many of the other ones are similar to the Gibson line (unsurprisingly)
Sending an email to you right now for that website.
I just came across an Epiphone EA-50 in a pawn shop for $49.00 ! Oops, lucky for me it had a terrible 60hz hum. Would I be interested in it for %20.00 ? Oh Yeah ! Problem: every schematic I can locate shows this amp with a tube rectifier.Mine is 3 tubes- 1-12au7 2-6bq5.
S/n is A007137 -plainly marked EA-50 Kalamazoo,Mi.
It has 2 inputs loudness,treble,bass and power switch W/ pilot light above.
Thought maybe you could steer me in the right direction as to what Pacemaker I have. Any help/info would be appreciated. Thanks,Tex
Well.. damn that’s odd. I don’t think you have a EA-50. At least not anything close to stock. They didn’t have tone controls and every picture I can find has the side by side switch and light.
First question: How many tube holes are there?
Second : What is directly connected to the PT secondary?
As I note here : http://www.paleoelectronics.com/blog/?p=27
it’s not uncommon for people to mod these with a set of diodes. In this amp especially, it’s a bad idea because there is no standby switch. Much better to use a “Copper Cap” replacement… fits in like a tube, has a delay to protect other tubes and is fully solid state.
It sounds like someone has done some weird stuff to your amp. The EA-50 is the EXACT same circuit as the GA-5 (Crestline) that I run daily. It should have a 6X4 rectifier, 6EU7 Preamp, 6C4 Phase Splitter and two 6AQ5′s in a push pull output scheme.
The 6BQ5/EL84 are pretty pricey. In fact, if both of your’s are in good condition, you can sell them, get 6AQ5′s and still be in the profit zone for the amp!! Assuming of course that the 6AQ5′s are the right tube for your amp.
I have to strongly suggest that you draw the exact circuit you have. Compare it to the EA-50/GA-5 schematic. It’s hard for me to believe that you have an EA-50. Nothing obvious comes to mind.
If you get me some more info about your amp, I’ll start a thread here and we can troll for help :-)
I’ll send you my email address.
Well,here we go–No mods! Has old style 2 diode rectifier, death cap, no chassis mods. 3 tube sockets,1 RCA 12AU7, 2 RCA 6BQ5,Back of chassis has only 1.5 amp fuse holder and UL sticker, Original “EPIPHONE”
EA-50
Kalamazoo,Michigan
Made in USA
Front is original, 2 inputs (one over the other,vertically,marked “instruments or mic.”) 3 control pots ,left of center,marked loudness,treble,bass( Blackface fender style knobs in dark gray color (matches tolex color), EPIPHONE
PACEMAKER lettering to right of center, power switch(rotary) with same gray knob as the others, pilot lamp above switch.
The only thing missing on this amp is the thin panel across the back directly below the chassis and the handle ( the remains of which are in the bottom of the cabinet). This thing has everyone who has seen it buffaloed. I’ll send pics if anyone’s interested in seeing this. Tex
Ok. got the pics. Here is what I think : http://www.angelfire.com/blues/rockinjohn/skylark_ga_5.html
Figure 6. I think you have a clone of a whiteface GA-5. I think you have diodes instead of a rectifier (obviously) and a transformer in place of the PI (this is a rare, but known design strategy).
The bad news is that this would be a departure from the standard GA clone model that Epi used to follow. In older models the EA-50 and GA-5 used the exact same schematics. Only the printing watermark was different.
So you are probably um.. challenged to find a diagram. However, just chasing hum might not be too bad without the diagram. First call is the power filter caps. That was enough for my GA-5
Well , maybe we have an idea what we’re dealing with. I appreciate the help.
Filter caps were where I was going to start, hopefully that will be as far as i need to go. This amp is so clean, pots are smooth as new,stock speaker looks great and sounded killer hooked to my Pro Junior! Have new tubes on the way from Tube Works. Gonna try JJ’s in this amp. I’ve had good luck with them in my Blues Junior and Pro Junior.Thanks again-Tex
Don’t cut off that two prong cord. What you have sounds like it is very rare. If it is unmodified, it’s value will stay high.
One of my next posts will describe how to do a three prong conversion without ruining the amp.
Check the angelfire website you referred me to. Figure 6 is exactly what my Pacemaker looks like with the exception of the speed and intensity knobs. Mine is non-trem. Otherwise the front panel and cabinet are the same. Epi didn’t change anything but the name and maybe the color of the tolex.
Also there’s a chance the 12AU7 should be a 6EU7 – potential for a hell of a hum if that’s the case.I don’t have one right now but as soon as I can scrounge one up I’ll let you know what happens. When I removed the 12AU7 the hum went away. If it’s a B+ hum I’d expect it to stay even with no preamp signal. We’ll find out –Tex
yeah yeah .. that’s what I’m saying (the figure six comment is directly below the url.)
I think you have the EA version with a Transformer PI and Diode rectification as factory designed.
Cant wait to hear how it sounds. Very good steal you got from the pawnshark