3rd gen 50 Watt

[talbany]

Marcos,
Initially my B+5 was 263V, and V1 was around 170V. the amp sounded great there, with a nice looseness about it. Just thought I'd try the higher voltages that were recommended by a few folks.

One thing I'm curious about is raising the cathode caps on V1 and V2 to at least 10uf. This is discussed a bunch in some "grailtone" threads. Good reading at any rate, https://tubeamparchive.com/viewtopic.ph ... rly++grail,
and one of the links from that thread... https://tubeamparchive.com/viewtopic.php?t=3615

Anyone tried the 10uf to 25uf values and liked the results?

I'm also interested in trying "high plate" for just the OD. Anyone done this to one of theses 50 Watts?

As an aside, I just found these 25uf/25V Spragues on sale for $1.70 at Newark...
http://www.newark.com/jsp/search/produc ... sku=18F852

Plate voltages on V1 &2 can be rather subjective.. The earlier 2nd & 3rd gen amps have a tendancy to be rather bright and using the 3 resistor (filter OD entrance network) can have a kind of beam y mid-range quality.. I have many here tell me it can be a bit harsh sounding at times (Pay close attention to lead dress on these amps)..The lower voltages helps with the brightness and slows the attack some and gives the amp more of an organic feel for me..(I find 180-185 to be perfect for my style)
Same thing with the bypass caps..(subjective) Although you have to be a bit more careful when raising the values in the lower power 50 watters..
My advice is to get out the alligator clips and clip in a few values first.. Sweep through different volume levels, gain settings and switching positions along the way to make sure that cap or caps work with all or most of the settings you like..Then solder them in..Most important have fun..

Tony

[telentubes]

Thanks for all the replies.
I ordered some of the silver 10uf Spragues and will give them a try. Clean is great so far. Mostly I want to smooth out the OD a little. At lower gain settings, it's nice and thick and sounds great, but it's a little grainy when going for that smooth sustainy OD thing these amps are famous for. I'll keep on tweaking. As an aside, this amp is dead quiet at idle.

Talbany, Thanks for the insight. Does my lead dress look about right in the photos?

[talbany]

Thanks for all the replies.
I ordered some of the silver 10uf Spragues and will give them a try. Clean is great so far. Mostly I want to smooth out the OD a little. At lower gain settings, it's nice and thick and sounds great, but it's a little grainy when going for that smooth sustainy OD thing these amps are famous for. I'll keep on tweaking. As an aside, this amp is dead quiet at idle.

Talbany, Thanks for the insight. Does my lead dress look about right in the photos?

Your lead dress looks fine I was just speaking in general with these amps.. Have you tried some older type pre amp tubes..These amps love the old RCA 12Ax's also get some time on the amp as well ..Just a suggestion..

Good Luck.

Tony

[telentubes]

I'm eying the RCA black plate 12AX7s, but the NOS price is a little intimidating. I'm looking at GEs which are a little more affordable.
I will spring for 12AT7s though, as they haven't gone through the roof yet.

I have a used set of RCA black plate 6L6s which I won't put in til I'm sure everything is O.K. The slight glow on one of the Winged C 6L6s is my concern. I assume it's just the tube but I'd hate to mess up an RCA.
I will get the NOS pre tubes eventually. Folks spend more on dinner.

[Max]

but it's a little grainy when going for that smooth sustainy OD thing these amps are famous for.

Just to avoid a misunderstanding: If a "smooth" OD sound like the one of RF, Larry Carlton, Carlos Santana etc.) should be what you like best, I would have some doubts, that one of the early OD circuits without snubbers, trigger entrance and ratio etc. (1st, 2nd and 3rd generation ODS) will be the one best suited for your personal taste. If such a "smooth" OD sound should be what you like best, then IMO one of the later "standard" OD circuits of the 4th and 5th generation ODS amps will perhaps make you more happy.

Of course you can make the OD sound of a 1st, 2nd and 3rd generation ODS sound "smooth", too. But IMO you'll have to do this more by playing your guitar in a "fat and smooth" way. IMO it's perhaps a bit easier to achieve a "smooth" OD sound with one of the later "standard" OD circuits. These early OD circuits of the 1st, 2nd and 3rd generation ODS amps are IMO a bit more unforgiving. That's exactly why I personally like these very much.

So if you should be in doubt concerning this "smooth OD" topic, then I would recommend to perhaps listen again to the clips of the 1st, 2nd and 3rd generation ODS amps you'll find in this thread: https://tubeamparchive.com/viewtopic.php?t=11906 just to make sure again that what you hear in these clips is the kind of OD sound you like best.

Cheers,

Max

[telentubes]

Hi Max,
Sound advice (no pun).
I think I will end up letting the circuit of this 50 Watt do what it does best and not try to make it into something it's not. I actually love the amp the way it is, and chose this model after lots of research and listening to sound samples. I need to dial it in the best I can (suggested voltages, tubes, tone shaping, bias settings, PI balance, etc) then build another circuit that has different strengths (creamy OD for instance), as you suggested. It's really been my plan all along. There are three models that I'm drawn to. I plan to build the next two when the time allows. The process (journey) is rewarding.