Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Planobilly on July 21, 2023, 05:05:50 pm
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Hi Guys
Been out sick for a long time. I am OK now and I want to build a Supro S-6424 using Steve's schematic. Link to the schematic. http://sluckeyamps.com/supro/supro.pdf
I will use the 6973 tubes and perhaps rewire it at some point to try EL84.
I assume the PT and OT will remain the same for both 6973 and EL84.
Hammond makes a PT with 600V CT at 173ma, 5VCT at 3A, and 6VCT at 5A, number 272FX.
PT datasheet, https://www.hammfg.com/files/parts/pdf/272FX.pdf
The Hammond OT is number 1760F. Datasheet https://www.hammfg.com/files/parts/pdf/1760C.pdf.
I have three or four new and vintage speakers that are 12" 8ohm Webbers or 16ohm Celestion greenbacks I want to try to use.
I will make a chassis, and I have all the other parts in stock.
I just need some advice on options for PT and OT and where is the best place to buy them.
Thanks,
Billy
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Just buy iron for a Deluxe Reverb. I would use the Hammond 1760H (https://www.hammfg.com/files/parts/pdf/1760H.pdf) OT.
Hawk has best Hammond prices...
https://www.hawkusa.com/
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I think the voltage resulting from a Deluxe Reverb PT will be pushing it for 6973s. PTs designed for the Marshall 18 are friendlier for those tubes, and in line with the iron Sluckey used. Except that Marshall uses a 9 pin rectifier.
The Hammond 290PAZ would be good I think.
If you want an Octal rectifier - It looks like the 290HBZ is close in spec.
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Thanks guys for the info.
I assume no two amps will exactly sound the same. I am not sure the transformer brands make a huge difference in sound.
Speakers do make a huge difference. Steve's comment about needing a Telecaster which may have been him joking about reproducing the sound he listen to on the internet actually is logical. For sure different guitars sound different and the same guitar with different pickups can sound very different.
My question about transformers was more about your experince with the sound of different brands. The cost is always an issue. I have bought a couple of Mercury Magnetics transformers
at twice the normal price but did not see the value.
There is a guy in San Diego who builds custom transformers. I installed one for someone who was super happy with the results but that is my only experence and all that is pretty subjective.
There is a lot of subjective stuff about tube amps. I have to smile at the tube amp purest who the first thing they do is put a transistor effects box on the input...lol
Cheers,
Billy
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Oh - my answer was strictly about getting close to the B+ voltages that the original and Sluckey's amp have.
Brands:
IMO I think its more about quality of construction and therefore longevity without any extraneous noises.
I'm a scrounger so I have used mostly used iron from old organs, PAs, Mono Hifi etc.
But I have also used many ClassicTone - sadly out of business. Hammonds and Musical Power Supply (he's having some supply chain issues these days)
They all sound the same to me - but I am not a very critical listener. Webers are less expensive and have some nice voltage options, but they are made in China and I think think those guys are listening in on my conversations.
Mercury Mags - Champagne prices for Cold Duck ears.
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This chunk of iron cost a ton of money. No more Mercury Mags for this kid...lol
(https://i.imgur.com/EvQPQH9.jpg)
I also listened to one of the Supros with reverb...This is an addiction...lol
Billy
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I bet they did. But it looks like you are going to have a great amp, and one you start playing it (with a Telecaster of course) you will forget about the cost. Heyboer supposedly bought some of ClassicTone's tooling and was going to make their Valco style iron. Not sure if that is still going to happen.
I'm glad you got healthy. Not the addiction - the other thing.