Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: CordovaNate on December 11, 2018, 11:56:14 am
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I saw this from a post from 2 years ago.
https://el34world.com/Forum/index.php?topic=21261.msg225429#msg225429 (https://el34world.com/Forum/index.php?topic=21261.msg225429#msg225429)
Would you still use that MV? It seems the dual pot "Type 2" MV gets more appreciation.
Thanks
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I haven't used the one in Slucky's version but I have built amps with across the line and LarMar MVs. I really prefer the Type II LarMar. There's more action throughout the range of the pot and it really dials in distortion a lot more smoothly and fully than the across the line.
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The LaMar Type 2 does seem to be more popular. This will be my 2nd build and I want to avoid changing anything after I build it. I do like the simplicity of that cross line type 3, but changing it to Type 2 might make me happier in the years to come.
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I lack the knowledge to build from a schematic and must rely on these layouts.
Here is my mark-up of the changes. Will this work?
If I could get the original and the markup side by side I would. I know it's a pain to download stuff to see it.
Thanks
Slucky...if you're looking, your original .pdf was titled pd1.pdf. I renamed it to be more meaningful to me.
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Looks like your added MV is OK, but you didn't quite get it right removing the old MV. I suggest this...
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Thank you for the corrections Slucky.
Forgive my asking, but does that .022 cap above the cut on the left do anything?
Anyway, package from Hoffman expect tomorrow, so I'll get to it. Maybe I'll have a new amp for Christmas!
Nate
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...does that .022 cap above the cut on the left do anything?
No, you can remove it.
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Thanks again Slucky,
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Now the dual pot is wired wrong.
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Two steps forward...2 steps back.
I've spent hours last night reading about master volumes and phase inverters. So, 2 steps back.
I have a PR I built two years ago.
I never use the tremolo.
I put in a switch to lift the NFB. I also changed the mid resistor from 6.8K to 10K.
My favorite sound is NFB lifted, vol on ~3, bass~5, treble~3. I'd like a touch more of that without the volume. I like it with NFB too and switch back and forth often.
I have pedals: Boss BD-2, Barber Small fry, BBE Green Screamer, etc., and don't use any of them.
I have a Weber MicroMASS 15 watt, but if a master volume is roughly equivalent, I'd prefer less clutter and knob would replace useless-to-me tremolo.
I don't play anything well, but the sounds I like to play badly: Jonny Lang, Larry Carlton, Robert Cray, Eric Clapton, etc.
Whether this build will get me closer to what I'm looking for, I don't know. But losing the tremolo and gaining a mid and a master volume control on the front panel makes it worth the effort to me. At this point, considering the relatively mild distortion and bedroom volumes the amp will be used for, I'm not sure that it matters which MV I choose.
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OK you have got me interested in this too. I have a Hoffman Princeton reverb w/o tremolo and bigger transformers and 6L6 tubes that I built several years ago, and hate having that half tube in there doing nothing. I might rebuild to this layout. I will keep an eye on your progress.
Thank you
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Yeah! I'm gonna go for it, assuming I got the MV wiring corrected. New board and supplies from Hoffman arrived today!
Nate
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My implementation of the "Fronelli" master volume did not work very well. From a full volume 10 to around 2.5, the volume didn't really change much, just the tone. But, I'd say there is a good chance I did something wrong.
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So, and in conclusion!
I went back to Slucky's as design, more or less. Layout is slightly different but circuit is the same.
And now I'm very happy with the results. The master volume works very well. Good granularity across the range of the MV pot, and I don't notice any change in tone.
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Good looking work. I haven't gotten into mine yet, but I think just a matter of time.
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Thank you BruceF.
I think I'd like to go back to a split tail PI, maybe next years project. This amp sounds good, but, and this may only be my imagination, I'm missing some of the "swirl/chime/3D/harmonics" that the stock HPR had. If the stock HPR was a 10 in this regard, I'd rate this amp at 8.5 or 9. Not much to complain about. Still...idle hands and all.
And my thanks, again, to sluckey for his time and input.