Comments on: Background http://www.paleoelectronics.com/blog/2007/09/background/ Clueless Idiots and High Voltage Vacuum Tubes Really Do Mix! Thu, 01 Jul 2010 22:19:08 +0000 hourly 1 http://wordpress.org/?v=3.0 By: Dilapidus http://www.paleoelectronics.com/blog/2007/09/background/comment-page-1/#comment-27 Dilapidus Wed, 02 Jan 2008 05:17:59 +0000 http://www.paleoelectronics.com/blog/?p=11#comment-27 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 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

]]> By: Tex http://www.paleoelectronics.com/blog/2007/09/background/comment-page-1/#comment-26 Tex Wed, 02 Jan 2008 04:41:30 +0000 http://www.paleoelectronics.com/blog/?p=11#comment-26 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 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

]]> By: Dilapidus http://www.paleoelectronics.com/blog/2007/09/background/comment-page-1/#comment-25 Dilapidus Tue, 01 Jan 2008 23:14:47 +0000 http://www.paleoelectronics.com/blog/?p=11#comment-25 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. 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.

]]> By: Tex http://www.paleoelectronics.com/blog/2007/09/background/comment-page-1/#comment-24 Tex Tue, 01 Jan 2008 22:40:40 +0000 http://www.paleoelectronics.com/blog/?p=11#comment-24 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 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

]]> By: Dilapidus http://www.paleoelectronics.com/blog/2007/09/background/comment-page-1/#comment-23 Dilapidus Mon, 31 Dec 2007 18:03:15 +0000 http://www.paleoelectronics.com/blog/?p=11#comment-23 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 <i>exact</i> 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 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

]]> By: Tex http://www.paleoelectronics.com/blog/2007/09/background/comment-page-1/#comment-22 Tex Sat, 29 Dec 2007 16:03:41 +0000 http://www.paleoelectronics.com/blog/?p=11#comment-22 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 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

]]> By: Dilapidus http://www.paleoelectronics.com/blog/2007/09/background/comment-page-1/#comment-21 Dilapidus Sat, 29 Dec 2007 06:38:10 +0000 http://www.paleoelectronics.com/blog/?p=11#comment-21 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.. 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.

]]> By: Tex http://www.paleoelectronics.com/blog/2007/09/background/comment-page-1/#comment-20 Tex Sat, 29 Dec 2007 05:00:38 +0000 http://www.paleoelectronics.com/blog/?p=11#comment-20 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 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

]]> By: Dilapidus http://www.paleoelectronics.com/blog/2007/09/background/comment-page-1/#comment-19 Dilapidus Wed, 07 Nov 2007 02:06:34 +0000 http://www.paleoelectronics.com/blog/?p=11#comment-19 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. 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.

]]> By: C Murphy http://www.paleoelectronics.com/blog/2007/09/background/comment-page-1/#comment-18 C Murphy Wed, 07 Nov 2007 01:13:28 +0000 http://www.paleoelectronics.com/blog/?p=11#comment-18 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 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

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