The Amp Garage

Thanks Aaron ! How does it sound with those huge caps on output stages ? I had quite a few Bruno's, none of them were perfect when I looked inside, some were better than others and some were problematic (I got one UG15 wired on tag strip that had issues) but I loved those amps and there're still amo...

As I’m building an amp with a second tube for CF and still putting down a proper layout I noticed it could be quite easy to design an amp with the CF stage, have a good listen then quickly rewire the amp and bias section to remove that one and try the amp with a regular PI. Maybe going back and fort...

Quite interesting ! I noticed on the block diagram of a 150W ODSR he used on the same taps as the rectifier another rectifier on each side (a resistor and a diode) to form a negative bias supply then use a 4k7 alter the choke (with its filtering cap) for the CF (DC coupled of not) stage and a 470R f...

Very nice, thanks guys ! As a CF newbie is it ok to use those two “bias” network on each side of the B+ (22k/1N4007) joined together for bias supply ? Also the Sultan seems to use choke vs resistors. That might be AN wanting more headroom from the amp. What puzzled me a bit is the reverb supply. Usu...

Thanks Tubedogsmith !

ODSR 60 is the only one I can think of, supposed to be 180k/1k and 130k/1.8k on the clean side. Low plate on the OD side.

You could use a 10k pot in serie with the 820R feedback R and be done with it.

Seems to me I saw a photo of a D amp with a fan mounted on the bottom of the head cab. You already have a cutout in the front panel, no? A small muffin fan could push air out through the grille cloth. You could test that idea out pretty easily, powering the fan from some external source just to see...

norburybrook wrote: ↑Sun Apr 05, 2020 5:32 pm I noticed that compared to #1,2,3,4 this amp has one pre amp tube less. Why is that? I presume it's a single rather than dual tube reverb, yes, no?


M

Yes it seems so. More Fender style reverb (2 tubes) rather than 3 for others SSS.

Thanks a lot for that !!

I was rebuilding a Wonderland and tried today a Skyline mod on it, keeping the same bass pot and tail and quite like it.

Do you have the values of the dropping resistors for the power supply ?
That’s a very important parameter.

The artificial center tap is by design well balanced and could yield a quieter amp. The CT from the transformer could be off balanced (not exactly on the middle of that secondary).

I hear you Tony. The scope of this thread wasn’t about if NOS parts get you the Ferrari, but if we can get really close by not using Ferrari Parts, but e.g. readily available Lamborghini parts. OK!. So my question back would then be? How close do you want to get? :wink: BTW. I think I'll do a video...

I would use the EH6V6 up to 400V, not more, and 70% max dissipation or even less (I shoot for 66-67%) and have a good amount of time available on the tubes yet they lost power after a while and need to be changed often (that’s my experience only on a a few amps for a few years). Good thing about the...

Replace the sockets that show signs of arcing. May be a good idea to just replace both. the arcing looks like its only from the metal pins at the top where the heater cable is wired in the top holes, the brown base is completely clear. what about the 175v AC heater readings? M I could be wrong but ...

Extra fuse on the B+ line at least is needed for the amp to be EU certified hence why they use one (beside the extra protection this will provide). Don’t know if a fuse for the heater winding is a necessity by the book for that certification, could be, but HT fuse is one. Take a look at current prod...

Same for me. Did try the Takman back then, CF and MF and overall not impressed especially considering the price. Told myself these were not a good choice for guitar amp.
I liked tantalum (got some AN ones) but pricey !!