Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: davent on May 07, 2020, 06:56:33 pm
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In 2016 i'd built this to the point of only needing to add, wire up the power transformer, an Antek AN-1T200 i had. One thing led to another and last month i got around to installing that transformer.
Summary, 6aq5 output tubes, solid state rectifier, London Power powerscaling circuit i've used a number of time, here scaling the PI & PA, bootstrapped master volume again from O'Connor, voltage regulated the power supply for the preamp using a regulator circuit from a phonopre, in the preamp ps bypass caps are plastic 2.2uF. I had some 6eu7's so wired sockets for those in parallel with the 12ax7 sockets and at the moment using a 6eu7 for V2 and a GE5751 for the PI.
Took me a few 5879's to find the amp did work once there was a working tube in V1 but... needed to swap OT primaries to kill the howl when full up. Never built or played an amp with this tonestack and in my combining of various schematics to work from, i for some reason had an extra wire in there basically bypassed the tonestack, no wonder the tonestack effect was so subtle/nonexistant.
Today installed a 33k grid stopper on the first triode as seen in the latest schematics i found in a search yesterday..
Only speaker cab i have has a Legend GB128, output transformer is an Edcor Xpp10-8-10k.
I'm really enjoying the sound, fun to play but i haven't found the clean settings yet, it's very crunchy, very very crunchy, i like that, clean is nowhere to be found ... so far. Perhaps i have more amiss discoveries to make.
The wood store i need to get to has been buttoned up for weeks so no telling when a cab for this might get made. I'd like to do my first hardwood cab using something local, another four year quest. Also need to find some more 12ax7 tube retainers..
Thanks to all that contributed to the original design and everyone who's contributed since, fun project!
(https://i.imgur.com/X8faDZLl.jpg)
(https://i.imgur.com/8xsbolKl.jpg)(https://i.imgur.com/F2POPodl.jpg)
(https://i.imgur.com/e99KVSYl.jpg)
(https://i.imgur.com/nrnNMnUl.jpg)
(https://i.imgur.com/6ajSa8ql.jpg)
(https://i.imgur.com/xK6J4myl.jpg?2)
(https://i.imgur.com/2UiUHMwl.jpg)
(https://i.imgur.com/YXDrpVtl.jpg)
dave
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In 2016 had this built
and a nice build it is!
a schematic will help you find clean if you can't find it with knobs.
try guitar at 3, gains at 3, tone at 5, all OD stuff & "effects" off, no soundsucker, just speaker, play a happy song and bring up MV till it quits being happy, call that 1 :icon_biggrin:
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In 2016 had this built
and a nice build it is!
a schematic will help you find clean if you can't find it with knobs.
try guitar at 3, gains at 3, tone at 5, all OD stuff & "effects" off, no soundsucker, just speaker, play a happy song and bring up MV till it quits being happy, call that 1 :icon_biggrin:
Thank you! Will give the gentle approach a try tomorrow, happy song, tough call.
dave
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i haven't found the clean settings yet, it's very crunchy, very very crunchy, i like that, clean is nowhere to be found ... so far
Try changing the .047 going into the LTPI to .0047 (or .01)
You have done a GREAT job on building that amp! The chassis interior layout and wiring is superb! :thumbsup:
With respect, Tubenit
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i haven't found the clean settings yet, it's very crunchy, very very crunchy, i like that, clean is nowhere to be found ... so far
Try changing the .047 going into the LTPI to .0047 (or .01)
You have done a GREAT job on building that amp! The chassis interior layout and wiring is superb! :thumbsup:
With respect, Tubenit
Thank you very much, your input to the forum was invaluable in getting the amp together. Listening to some of your clips yesterday showed there was another voice hiding inside the amp i hadn't found. I probably based my eyelet board layout on yours.
The power of the volume knob, i didn't know there was life under ten. I went with @shooter's set -up suggestions this morning and there it was, clean, not loud but it is a nice pleasant side of things to explore. Even with the master volume up full, stays clean, roll up the guitar volume and away we go again, super!
Will keep the cap change on the books for another day, an easy swap, thank you!
a schematic will help you find clean if you can't find it with knobs.
try guitar at 3, gains at 3, tone at 5, all OD stuff & "effects" off, no soundsucker, just speaker, play a happy song and bring up MV till it quits being happy, call that 1 :icon_biggrin:
Thanks @shooter
Stay well all!
dave
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:icon_biggrin:
I can't tell an E from a G, no clue about Pentatonic scales
I am surprised the number of actual guitar players I've duck-taped their fingers to the guitar so I could set knobs :laugh:
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davent,
Beautiful build! I am glad that the Hoso56 is out of the archives and back in the headlines. It seems like a transcendent amp.
Have any clips of drive vs. clean?
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davent,
Beautiful build! I am glad that the Hoso56 is out of the archives and back in the headlines. It seems like a transcendent amp.
Have any clips of drive vs. clean?
Thanks @boodle. I'm enjoying my new toy, i seem to have only scratched the surface as to what it's capable of, the clean is only half a day old.
I'm not at all set up do any recording but my wife would tell you, you should be able to hear it from here.
All the best with your build, am following along.
Take care!
dave
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Will keep the cap change on the books for another day, an easy swap, thank you!
I'm about 90% certain that the schematic (DaGeezer's) you worked off of had a typo listing the .0047 cap as .047. :icon_biggrin:
The other HoSo56 variations list .0047 or .01. As an FYI, a Fender Super Reverb has a .001 in that position.
Using a .047 would give a dramatic change in tone from the intended .0047. However, IF you like the way it sounds then it's great & don't change it. When I've tried large caps in that position (bigger then .02), I lost a tremendous amount of transparency and articulation. Playing a chord, I could no longer distinguish the individual notes and it all kind of mushed together.
Not saying you "should" change it as it may be more to your liking?
With respect, Tubenit
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Will keep the cap change on the books for another day, an easy swap, thank you!
I'm about 90% certain that the schematic (DaGeezer's) you worked off of had a typo listing the .0047 cap as .047. :icon_biggrin:
The other HoSo56 variations list .0047 or .01. As an FYI, a Fender Super Reverb has a .001 in that position.
Using a .047 would give a dramatic change in tone from the intended .0047. However, IF you like the way it sounds then it's great & don't change it. When I've tried large caps in that position (bigger then .02), I lost a tremendous amount of transparency and articulation. Playing a chord, I could no longer distinguish the individual notes and it all kind of mushed together.
Not saying you "should" change it as it may be more to your liking?
With respect, Tubenit
Well now i'm going to have to try it. Have my stack of printouts here and sure enough all three values to be found. Have lots of each and in between, the cap spans the distance between the treble pot and my master volume so very easy to access and change.
Thank you for the heads-up, will become more acquainted, comfortable with what i have at the moment and then do a swap. I have an amp based on a 5c1 that has six coupling caps on a rotary switch to alter the 'body' of the signal depending on the guitar i'm using, maybe i should just borrow that... nah.
Thanks again @Tubenit!
Stay well,
dave