Output Transformer for Wurlitzer model 503 amplifier from 1015
I have an amplifier to repair from a W1015 and it requires an output transformer. My usual Hammond “go to” replacements will be too tall as this one is mounted underneath the chassis. Just wondering what others use here? Preferably Hammond as I’m in Canada. Thanks, Mauro Sent from my iPhone
On 2025-12-02 2:34 p.m., M De Simone via Jukebox-list wrote:
I have an amplifier to repair from a W1015 and it requires an output transformer. My usual Hammond “go to” replacements will be too tall as this one is mounted underneath the chassis. Just wondering what others use here? Preferably Hammond as I’m in Canada. Thanks, Mauro
Hi Mauro, Talk to the people at Hammond about your problem, I'm sure they can help! I met Fred Hammond back in the 60s at a meeting of the CVWA (Canadian Vintage Wireless Assoc.) in Toronto (I was a teenage radio collector and editor of the Cat's Whisker - our club newsletter) and we had a nice chat, he was all for supporting tube stuff and as far as I know the factory still is happy to help when they can! John :-#)# -- John's Jukes Ltd. 7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3 Call (604)872-5757 (Pinballs, Jukes, Video Games) flippers.com "Old pinballers never die, they just flip out"
John, The people at Hammond are still terrific! A gentleman by the name of Doug Hutt has been a resource for years, I once called him about a transformer for a Music Mite, they had a good sub but was missing one lead, I think it was a centre tap. About 8-10 later I received the transformer in the mail with the extra tap, NO CHARGE!! I had no idea he was going to do that. Great and very knowledgeable man, unfortunately he passed suddenly about 5 years ago. I spoke to another engineer there and asked who would be replacing him, both he and another administrator said, “he cannot be replaced”. Perhaps I’ll call and see if they have any recommendations. Thanks John, for the suggestion. Sent from my iPhone
On Dec 2, 2025, at 5:53 PM, John Robertson via Jukebox-list <jukebox-list@lists.netlojix.com> wrote:
On 2025-12-02 2:34 p.m., M De Simone via Jukebox-list wrote:
I have an amplifier to repair from a W1015 and it requires an output transformer. My usual Hammond “go to” replacements will be too tall as this one is mounted underneath the chassis. Just wondering what others use here? Preferably Hammond as I’m in Canada. Thanks, Mauro
Hi Mauro,
Talk to the people at Hammond about your problem, I'm sure they can help!
I met Fred Hammond back in the 60s at a meeting of the CVWA (Canadian Vintage Wireless Assoc.) in Toronto (I was a teenage radio collector and editor of the Cat's Whisker - our club newsletter) and we had a nice chat, he was all for supporting tube stuff and as far as I know the factory still is happy to help when they can!
John :-#)#
-- John's Jukes Ltd. 7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3 Call (604)872-5757 (Pinballs, Jukes, Video Games) flippers.com "Old pinballers never die, they just flip out"
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I just checked the Hammond catalog and couldn’t find one that would fit. I’m curious if others have a solution or they drill the chassis and mount a replacement topside? Thanks, Mauro Sent from my iPhone
On Dec 2, 2025, at 7:30 PM, M De Simone <m.desimone@rogers.com> wrote:
John,
The people at Hammond are still terrific! A gentleman by the name of Doug Hutt has been a resource for years, I once called him about a transformer for a Music Mite, they had a good sub but was missing one lead, I think it was a centre tap. About 8-10 later I received the transformer in the mail with the extra tap, NO CHARGE!! I had no idea he was going to do that. Great and very knowledgeable man, unfortunately he passed suddenly about 5 years ago. I spoke to another engineer there and asked who would be replacing him, both he and another administrator said, “he cannot be replaced”. Perhaps I’ll call and see if they have any recommendations. Thanks John, for the suggestion.
Sent from my iPhone
On Dec 2, 2025, at 5:53 PM, John Robertson via Jukebox-list <jukebox-list@lists.netlojix.com> wrote:
On 2025-12-02 2:34 p.m., M De Simone via Jukebox-list wrote: I have an amplifier to repair from a W1015 and it requires an output transformer. My usual Hammond “go to” replacements will be too tall as this one is mounted underneath the chassis. Just wondering what others use here? Preferably Hammond as I’m in Canada. Thanks, Mauro
Hi Mauro,
Talk to the people at Hammond about your problem, I'm sure they can help!
I met Fred Hammond back in the 60s at a meeting of the CVWA (Canadian Vintage Wireless Assoc.) in Toronto (I was a teenage radio collector and editor of the Cat's Whisker - our club newsletter) and we had a nice chat, he was all for supporting tube stuff and as far as I know the factory still is happy to help when they can!
John :-#)#
-- John's Jukes Ltd. 7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3 Call (604)872-5757 (Pinballs, Jukes, Video Games) flippers.com "Old pinballers never die, they just flip out"
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On 12/2/25 17:33, M De Simone via Jukebox-list wrote:
I just checked the Hammond catalog and couldn’t find one that would fit. I’m curious if others have a solution or they drill the chassis and mount a replacement topside?
Give us some more details. Maximum height, mounting hole pattern, any odd speaker taps needed, are there screen grid taps. I'm assuming a pair of 6L6s, correct? -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
Hi Jay, Thanks for responding. There are 2 mounting holes 3 5/8” apart. The height is 2 1/2” The frame width is 3 1/8” The windings are 2 1/4” wide. Of course it’s 2 6L6G output tubes. I just looked at the Hammond 125E and it will likely fit but I’m not sure it’s heavy enough to handle this. It’s a max output of 15W. Mauro Sent from my iPhone
On Dec 2, 2025, at 10:12 PM, Jay Hennigan via Jukebox-list <jukebox-list@lists.netlojix.com> wrote:
On 12/2/25 17:33, M De Simone via Jukebox-list wrote:
I just checked the Hammond catalog and couldn’t find one that would fit. I’m curious if others have a solution or they drill the chassis and mount a replacement topside?
Give us some more details. Maximum height, mounting hole pattern, any odd speaker taps needed, are there screen grid taps. I'm assuming a pair of 6L6s, correct?
-- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
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On 12/2/25 19:36, M De Simone via Jukebox-list wrote:
Hi Jay, Thanks for responding. There are 2 mounting holes 3 5/8” apart. The height is 2 1/2” The frame width is 3 1/8” The windings are 2 1/4” wide.
Of course it’s 2 6L6G output tubes.
I just looked at the Hammond 125E and it will likely fit but I’m not sure it’s heavy enough to handle this. It’s a max output of 15W.
I think it will work and that's what I would have chosen in that form factor. Keep in mind that the 6L6/6L6G is not nearly as beefy as the 6L6GC and 15 watts seems to be typical if not a little high for a pair of them push-pull. What's the weight of the old transformer? The 125E weighs 1.5 pounds which will give a reasonable idea of how much iron and copper are in it. -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
The 1760J is another possibility. Rated at 40W, seems closer to your dimensions. The 2.63 inch height might be an issue. See also 1760JB. https://www.hammfg.com/files/parts/pdf/1760J.pdf https://www.hammfg.com/files/parts/pdf/1760JB.pdf -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
Jay, I missed the 1760 series on the website, thanks for pointing them out. I really like the 1760JB as a replacement but it’s going to be a very tight fit. The top of the transformer will be touching the bottom plate and the core will be tight up against the relay but I’m very confident I can tuck it in there. Thank you for your research and recommendation, as always you really helped me out. I think this is the right choice! Appreciated, Mauro Sent from my iPhone
On Dec 2, 2025, at 11:18 PM, Jay Hennigan via Jukebox-list <jukebox-list@lists.netlojix.com> wrote:
The 1760J is another possibility. Rated at 40W, seems closer to your dimensions. The 2.63 inch height might be an issue. See also 1760JB.
https://www.hammfg.com/files/parts/pdf/1760J.pdf
https://www.hammfg.com/files/parts/pdf/1760JB.pdf
-- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
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Hi Mauro, Fred Hammond used to tell me that the transformers they made were derated upwards of 50%. You may want to give the techs a call and see if the smaller transformer (125E) that fit better will handle the output of a Class A (AB?-Jay?) pair of 6L6Gs. The output is conditional on the B+, not the tube bulb style (maximum heat dissipation issues in the metal tube), if the original amp was 310VDC at the plate - that would make it around 18W output based on my GE Tube book from 1964 if operated as Class AB(1), 47W if operated at AB(2) which I really doubt, and I don't know how to tell anyway. My RCA book lists the 6L6G, run Push-Pull at 270VDC in Class A, is rated at 18.5W @ 134ma, P-P 360VDC Class AB(1) is rated at 26.5W. John :-#)# On 2025-12-03 11:46 a.m., M De Simone via Jukebox-list wrote:
Jay, I missed the 1760 series on the website, thanks for pointing them out. I really like the 1760JB as a replacement but it’s going to be a very tight fit. The top of the transformer will be touching the bottom plate and the core will be tight up against the relay but I’m very confident I can tuck it in there. Thank you for your research and recommendation, as always you really helped me out. I think this is the right choice! Appreciated, Mauro
Sent from my iPhone
On Dec 2, 2025, at 11:18 PM, Jay Hennigan via Jukebox-list <jukebox-list@lists.netlojix.com> wrote:
The 1760J is another possibility. Rated at 40W, seems closer to your dimensions. The 2.63 inch height might be an issue. See also 1760JB.
https://www.hammfg.com/files/parts/pdf/1760J.pdf
https://www.hammfg.com/files/parts/pdf/1760JB.pdf
-- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
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-- John's Jukes Ltd. 7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3 Call (604)872-5757 (Pinballs, Jukes, Video Games) flippers.com "Old pinballers never die, they just flip out"
On 12/3/25 12:19, John Robertson via Jukebox-list wrote:
Hi Mauro,
Fred Hammond used to tell me that the transformers they made were derated upwards of 50%. You may want to give the techs a call and see if the smaller transformer (125E) that fit better will handle the output of a Class A (AB?-Jay?) pair of 6L6Gs.
Push-pull is going to be class AB. Class A power stages are single-ended, hot, and horribly inefficient with arguably very slightly higher fidelity in some cases.
The output is conditional on the B+, not the tube bulb style (maximum heat dissipation issues in the metal tube), if the original amp was 310VDC at the plate - that would make it around 18W output based on my GE Tube book from 1964 if operated as Class AB(1), 47W if operated at AB(2) which I really doubt, and I don't know how to tell anyway.
It's going to be AB1. AB2 is more complex as it drives the grids positive and the drivers need to be designed to handle this. Also keep in mind that the 6L6 (metal) and 6L6G are rated for substantially lower plate voltage and power output than the 6L6GC. This amplifier was designed for the lower voltage tubes as 6L6GC didn't exist yet.
My RCA book lists the 6L6G, run Push-Pull at 270VDC in Class A, is rated at 18.5W @ 134ma, P-P 360VDC Class AB(1) is rated at 26.5W.
I suspect the stock Wurlitzer amplifier is rated somewhere around 20 watts output. The 1760JB transformer looks much closer in physical size to Mauro's original and is rated at 40 watts with 6K ohms plate impedance, a good match to 6L6s in push-pull. It's going to be a better electrical fit with plenty of headroom in terms of power if he can shoehorn it in there. The 125E will probably work as Hammond makes good goods that are very conservatively rated. I'm a bit concerned about the DC bias rating of the 125E at 60mA in this application. -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
On 12/3/25 11:46, M De Simone via Jukebox-list wrote:
Jay, I missed the 1760 series on the website, thanks for pointing them out. I really like the 1760JB as a replacement but it’s going to be a very tight fit. The top of the transformer will be touching the bottom plate and the core will be tight up against the relay but I’m very confident I can tuck it in there. Thank you for your research and recommendation, as always you really helped me out.
I wonder if you can shim the bottom plate out 1/8 of an inch or so to avoid contact. It might interfere with the magnetic path if it's touching, assuming a steel chassis and bottom plate. I think that the amplifier might acoustically "sing" along with the music if it touches. A small thin insulating sheet such as fish paper or G-10 board is another possibility. As it's shown as a maximum spec, the actual dimension may be a little less. It looks like this transformer has covers over the windings on both sides, you can probably pry off the mounting strap and remove them if necessary to gain side clearance. Happy to help. -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
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M De Simone