Vintage Epiphone combo
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- martin manning
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Re: Vintage Epiphone combo
Well that's a pretty good clue. My money is still on 6k6 for the primary impedance. If that's the PT and Reverb driver in the pic, where are the choke and OT? There are two chassis (photo in first post), right? Maybe the choke is mounted on the floor of the cabinet (only two wires needed)? Electrically it's before the plate node so it's going to be big to carry all that current.
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Re: Vintage Epiphone combo
This a pic of the PT (left) and OT (right). The reverb txt is further to the right. Here is a pic with code.andresound wrote:OT looks small to me . Herewith pic of chassis and PT + reverb driver
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Re: Vintage Epiphone combo
Sorry this pic is the PT & OT
This is the PT code
This is the PT code
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Re: Vintage Epiphone combo
Input section. 4x 100k grid stoppers (same as GA-77).
Also the reverb section (2 grey cables go to the reverb transformer).
Also the reverb section (2 grey cables go to the reverb transformer).
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Re: Vintage Epiphone combo
Cathode bias resistor and cap (I have replaced the cap)
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- martin manning
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Re: Vintage Epiphone combo
EIA code 166 is Magnetic Components; still in business today and very active in the instrument amp field. The 200R Rk is as shown in the EA-10's 6L6 output section, and the GA-77 designation on the OT makes it 6L6 family (5881). It's looking like the EA-10RV is EA-10 plus the reverb and PI from the GA-77. Are the tone control circuits like the EA-10 schematic?
Re: Vintage Epiphone combo
There seems to be less and less GA-77RV as we go along. It looks like there's no choke. I think I can make out a wirewound off one of the output tubes in the original pic. Probably between plates and screens. The 77 was fixed bias and had separate tone controls for each channel. The EA-10 had three tone controls fed from a DC coupled cathode follower (so did the GA-70). I can't tell if there's a follower circuit in this one, but the tone circuit looks like a pair of "Tweed" style bass cut and treble cut controls.
- martin manning
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Re: Vintage Epiphone combo
As shown in the EA-10's power supply.Firestorm wrote:It looks like there's no choke. I think I can make out a wirewound off one of the output tubes in the original pic. Probably between plates and screens.
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Re: Vintage Epiphone combo
Cathode bias resistor and cap (I have replaced the cap)
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Re: Vintage Epiphone combo
Yip there is a 6k 4watt wire wound as the above and no choke per se.martin manning wrote:As shown in the EA-10's power supply.Firestorm wrote:It looks like there's no choke. I think I can make out a wirewound off one of the output tubes in the original pic. Probably between plates and screens.
The tone stack does not have a mid pot.
Volume 1, Volume 2, bass, treble and the reverb.
Noticed I only have mostly Poly prop caps from an old X-over project, so I have to order bypass caps and PS caps. Any suggestions on a source for these?
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- martin manning
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Re: Vintage Epiphone combo
Like the BA-15? I guess they needed the third tone control's chases hole for the reverb knob.andresound wrote:The tone stack does not have a mid pot... Volume 1, Volume 2, bass, treble and the reverb.
The two brown coupling caps near the output tubes appear to be oozing wax or something, and probably should be replaced. Are you looking for a local source or somewhere outside ZA? If outside, what countries can you get parts shipped from most easily? EU? Oz?andresound wrote:Noticed I only have mostly Poly prop caps from an old X-over project, so I have to order bypass caps and PS caps. Any suggestions on a source for these?
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Re: Vintage Epiphone combo
I will replace those coupling caps Martin. I can order from States or EU. Tube type values are non existent in ZA
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- martin manning
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Re: Vintage Epiphone combo
Have you tried Antique Electronic Supply? They have lots of tube stuff, and they say they ship internationally, with lots of options: https://www.tubesandmore.com/customer-s ... d-delivery
- RJ Guitars
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Re: Vintage Epiphone combo
Ah rats... I just sent those knobs to you and I could added a handfull of coupling caps if I had seen this coming.
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Re: Vintage Epiphone combo
Not to worry Bob, I will be doing a decent order from you sometime soon. As soon as this project is done . Damm.. I need counselling
If it sounds good, it is good! Trust your ears