Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: ebulakowski on November 07, 2023, 03:21:05 pm
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I recently bought a Brownface deluxe 6g3 from the original owner! This is the cleanest amp I have been inside. I am near certain no one else has ever removed the chassis. I put it up on my bench knowing I would likely be replacing the electrolytics and installing a 3 prong cord. Then I started to notice some peculiar things.
All went smooth, but when I turned my attention to the bias board, and was very surprised to see a 4.7k resistor in parallel with the electro. Then, I noticed there was a dedicated bias tap, and that my voltages overall were higher. 420v-ish. As i started to look at schematics and other examples, I came to realize that the transformer in this amp is a 125P23B (deluxe reverb model).
I guess my question is, has anyone else seen this transformer used in the brownface 6g3? This amp dates July '63. and again, I am near certain no one has worked on this amp.
Is there anything I should check or be concerned about with the higher voltages. My thought is to pull the original oxford (which I have heard is a bit under spec'ed) to keep it in good shape.
Any thoughts overall?
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What's the date code on the PT?
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According to Hammond specs for their 290BX, it is interchangeable with both the 125P2A (specified in 6G3 schematic) and the 125P23B (Deluxe Reverb PT), so I suspect this is another one of those mid-stream parts changes made by Fender that was never really documented.
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What's the date code on the PT?
The power transformer is 606313, so earlier '63
Tube chart is stamped MG, so July '63
oxford Speaker is 49th week of '62
Interestingly the transformer also features the Canadian C.S.A. Test Stamp.
Overall it sounds amazing! Mostly just curious if this was a common transition, or just the end of a run.
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According to Hammond specs for their 290BX, it is interchangeable with both the 125P2A (specified in 6G3 schematic) and the 125P23B (Deluxe Reverb PT), so I suspect this is another one of those mid-stream parts changes made by Fender that was never really documented.
I think that might be the case!
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Solder at transformer wires look original to my eyes.
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It look like a museum-piece inside.
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It indeed looks very original and in mint condition. I'd keep every original part if I was repacing anything to preserve value. How about some photos of the rest of the amp.
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Beautiful example. That heater wiring is so straight it looks like it was formed on a jig.
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It indeed looks very original and in mint condition. I'd keep every original part if I was repacing anything to preserve value. How about some photos of the rest of the amp.
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Wow! Very nice. Thanks.
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As requested!
Thanks everyone for chiming in. I Did replace all the electrolytics, as almost all were out of spec and visibly leaking. The only real change, was adding a bias pot on a Z bracket inside. I figured this was the most reversible/non invasive method. As well as a 3 prong in a modern scheme.
And yes, I have all the parts! I did pull the original GE tubes for now so I don't put any more miles on them at the moment. I am debating that with the speaker as well.
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I’m jealous, :icon_biggrin: . Nice score, l love the Brown Face Deluxe, nice clean tone but can get nasty too. Nice trem too.
Just wondering what it cost you in this day and age..?
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I’m jealous, :icon_biggrin: . Nice score, l love the Brown Face Deluxe, nice clean tone but can get nasty too. Nice trem too.
Just wondering what it cost you in this day and age..?
I dropped $2500 on it and a Gretsch (valco) stand alone reverb amp. I need to troubleshoot the gretsch. But the 6g3 was pretty cut and dry. Not inexpensive, but it felt like something to jump on given the condition and how much they've gone up. I've always wanted one from this era. Plus, it came with it's old canvas cover. :) But I will be selling off some other amps to recoup.
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I recently bought a Brownface deluxe 6g3 ... As i started to look at schematics and other examples, I came to realize that the transformer in this amp is a 125P23B (deluxe reverb model).
I guess my question is, has anyone else seen this transformer used in the brownface 6g3? This amp dates July '63. ...
The 125P23B is 100% original, and is expected given the late-date in brownface amp production.
I currently own a 1962 Deluxe, and used to also have a 1963 Deluxe (at the same time). The schematic says "125P2A" (https://el34world.com/charts/Schematics/files/Fender/Fender_deluxe_6g3.pdf) and never was changed to show anything else, but Fender used 3 different power transformers in this amp:
125P2A
125P17A - lower voltage than the prior model
125P23B
My 1962 Deluxe has the 125P17A power transformer. The 1963 Deluxe had would have used the 125P23B, but it had a replaced PT output a silverface Deluxe. The 125P23B transformer I had in a 1964 Deluxe Reverb I owned delivered very slightly less output voltage than the 125P17A (about 395v at 6V6 plates), and less voltage than the other PT models that followed it.
And of course, the 125P23B power transformer was carried on in the blackface Deluxe/Deluxe Reverb models. The Deluxe also had multiple changes of power transformers during the blackface era (and possibly again in the silverface era, though the different numbering system made it harder to observe a change).
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I recently bought a Brownface deluxe 6g3 ... As i started to look at schematics and other examples, I came to realize that the transformer in this amp is a 125P23B (deluxe reverb model).
I guess my question is, has anyone else seen this transformer used in the brownface 6g3? This amp dates July '63. ...
The 125P23B is 100% original, and is expected given the late-date in brownface amp production.
I currently own a 1962 Deluxe, and used to also have a 1963 Deluxe (at the same time). The schematic says "125P2A" (https://el34world.com/charts/Schematics/files/Fender/Fender_deluxe_6g3.pdf) and never was changed to show anything else, but Fender used 3 different power transformers in this amp:
125P2A
125P17A - lower voltage than the prior model
125P23B
My 1962 Deluxe has the 125P17A power transformer. The 1963 Deluxe had would have used the 125P23B, but it had a replaced PT output a silverface Deluxe. The 125P23B transformer I had in a 1964 Deluxe Reverb I owned delivered very slightly less output voltage than the 125P17A (about 395v at 6V6 plates), and less voltage than the other PT models that followed it.
And of course, the 125P23B power transformer was carried on in the blackface Deluxe/Deluxe Reverb models. The Deluxe also had multiple changes of power transformers during the blackface era (and possibly again in the silverface era, though the different numbering system made it harder to observe a change).
Thank you so much for this information! Exactly the insight I was hoping to find. Especially since I am loving this amp! Between this and a Drip edge Princeton reverb, I am very content.