Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: LooseChange on August 07, 2012, 11:24:29 am
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Haven't done one of these in ages. It is extremely quiet and sounds great.
The only change I made was the bias set resistor. 47k is too big. Changed it to a 22k and all is good.
Funny, there are very few pictures of these on the web... And one is mine from way back.
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Top notch work there Danny-boy! :thumbsup:
Hoffman layouts simply look very neat & professional.
G
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LC,
You always do such excellent work! That looks incredible.
With respect, Tubenit
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Very nice! I love that layout, and very clean wiring. Fantastic job!!!
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Very nice!
I'm currently building a 5F6A myself... One question if you don't mind: you don't have the 100ohms resistors on the lamp: have you got them on the power tubes? (between lugs 2 and 8 on one and lugs 7 and 8 on the other?) Or have you got a heater CT wire on your PT?
Thanks!
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The 100 ohm resistors are on the board. First two components on the far left. It's part of the Hoffman layout.
Thanks for all the nice words.
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The 100 ohm resistors are on the board. First two components on the far left. It's part of the Hoffman layout.
Thanks for all the nice words.
Hadn't spotted them... :BangHead:
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Thanks for the photo. Very nice. Love the use of the radial caps tucked under the ground rail.
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Yep, as always LC, very well done!
Brad :icon_biggrin:
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I've done a few reissue bassman hand-wired jobs over the years but I prefer the stock Fender layout.
I drop the voltage down to 430 on the plates and it sounds so much better than the almost 500v that the reissues have!
either layout obviously works.
Nice work Loose!
I love the original 12AY7 in V1 as it's feel is far superior to a 12AX7 IMHO.
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I used to do those conversions all the time. Like you, I haven't done one in quite some time. The second to the last time I did one, the buyer traded me his reissue for the Hoffman hand wired one. He brought his in and played both of them side by side with an A/B switch for about 20 minutes. Within the first minute or two even I could hear the major difference between them. The Hoffman 5F6-A sounded incredible with this fellow playing it as he was really good. The reissue had artifacts in the sound. A noise that just sounded awful that was present on almost every note. The buyer said he hadn't noticed the noise as "a noise" before but just hadn't liked the reissue's tone before. Playing them side by side made the noise really stand out. I even swapped out the tubes in the reissue and it was still there. I've always believed it was due to the layout of the PCB. I ended up rebuilding the buyers reissue and selling that to a local musician who loved it but didn't use it much because it was just too loud. He preferred his two Hoffman layout 5E3's I built for him for performing. He miked them to the P.A. I think that is what affects the sales of these amps. Lots of folks have gone to lower wattage amps now. Nice build there Dan! By the way, the noise in the reissue went away with a Hoffman board in it.