Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: shooter on March 08, 2015, 11:39:27 am
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I spent the winter down south refining last years proto-type , my interpretation of Sluckey’s interpretation of the Rock-ola. She is a chiming SE KT88 that is just smooth and sweet, till you get to 7, then she turns into a 5E1 champ on steroids. Thanks to all the big guns, and silver ones that showed me that quality still matters in a throw-away world.
I’m now back in the arctic waiting for the perma-frost to thaw so I can get a cab built. I put it in a 17” chassis but it should fit fine in Dougs 12” pre-drilled one if you use his PS layout for the Blues Jr or Plexi.
I’m playing through a 2X12 cab with a Eminence Legacy and a cream faced Rola Celestion G12, the combination is amazing!
dave
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Forgot the Schematic :think1:
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A proper chassis sure does make for a nice looking build. And yours is really nice and clean. :worthy1:
I'm really surprised that the entire amp is powered from the same B+ node.
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Originally it wasn't, I had the traditional 3. But since it was a prototype, test box, I reformed the caps from my junk box, after 2 exploded over time, I just cobbled a single tap and it seemed to work, so I stuck with it.
I even scrounged the blue one on the new board from the old build, and well, that was my 1st repair!!! now it has all new Illinois.
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Ok I can't quit playing, I have been putting in my pile of old 6sn7's. I have two in that sound like polished smoked glass, keepers! My question, I put in a tung-sol in V2 and it sounds like I opened the glass housing, coated everything with a thin layer of dryer lint then added a very mild fuzz box and closed it all back up, is that an indication of a dying tube? I think I'm getting what's "good" but I don't know what's "bad" tonally. hissy, sparky, crackly I get!!
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looks nice!
hmm... with the exception of the PS rail, that topology looks a lot like cosmo. :icon_biggrin:
COSMO (http://el34world.com/Forum/index.php?topic=15369.msg148206#msg148206)
--Pete
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I stole the pre from Sluckey and the PA is one I've done a couple times from various web hunts.
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Finally got it mounted in a cab I built last year for a proto-type. still got an annoying chassis-cab buzz with hard sustained bass, but I think i'll be moving it to a head cab when the barn thaws out!
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I haven't done much in an SE, so you guys have just spurred me on. Thanks
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I've only done 2 PP builds and they were both cathode biased, it's cold in MI so I like the heat :icon_biggrin:
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reviving the dead, past this amp to my Son for Christmas, finally got together yesterday to properly tune it for his liking, and the deafer I got, the happier he was :icon_biggrin:
here's the updated schematic and layout.
According to Matt, the tone fits nicely between a 5F2 tweed and a later blackface.
Finally a built that I Almost got fully documented, he wouldn't quit playing for final voltage checks :think1:
I do still have one academic question, the tone stack if dialed to zero, kills all the signal, as a player, is there any reason to keep the gain pot after the tone stack?
Thanks again to all that passed the proto-type and onto true functional builds.
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All Fender TMB stack will totally kill the volume if all tone pots are turned tom zero. Look at the schematic. You can put the volume pot anywhere you want. Fender liked the spot you show in your schematic.
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You can put the volume pot anywhere you want.
I get that, have done it on most *fenderish* builds, after 20hrs driving, I was wondering why even have it, when *vol* is basically set by the TMB, and the *next* stage could be just a fixed voltage divider.
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Soundclips? :icon_biggrin:
Jim
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> is there any reason to keep the gain pot after the tone stack?
More knobs == higher price.
Ask Son if he wants less knobs. Everybody has "one knob" (or no-knob) days; but mostly more knobs has to be better, right?
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For Keep It Simple Stupid guys like me.
Lots of knobs to turn, overwhelms my pea brain. :BangHead:
An amp with a single volume knob,
that sounds great wherever you turn it to,
is the best amp for me. :l2:
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Ask Son if he wants less knobs
On my (P)/SE's he puts all volumes to 10, TMB to 5's, sets his guitar, then sets TMB and never(mosly) touches amp gain/vol. I do spent build time to ensure "10" doesn't make the amp squeal like a pig
I can see it on his twinRVB.