Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Megachunk on September 01, 2011, 05:53:55 pm
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Hello all.
I've once again revised my amp and have it wired not unlike the layout below. I am using El34's. I also wired a master volume type 3 (Single 1 meg pot). I'd like the option of this amster, as it's easy and sounds OK. It gets great OD at low volume, but barely turn it up (I mean minutely) and its back at full and clean. Not a lot of sweep before all up full. I have it wired to the points 14 and 16 on the layout. Junction of the 220K and .02 caps, which are now .1 caps. Am I right on this? Please let me know.
Thanks in advance.
Mike
Megachunk
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That's just the way that MV works. Not very useful IMO.
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Which would be better suited for this, Sir Luckey? I would like to have something to keep gain and pipe it down a hair.
Thanks,
Mike
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Look at reply #5...
http://www.el34world.com/Forum/index.php?topic=11422.0 (http://www.el34world.com/Forum/index.php?topic=11422.0)
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Thank you sir! Be trying it when the pots arrive!
Mega
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The schematic show in the EL34world in the post send by sluckey is the best and only good master volume. It did not change your tone. A good friend of mine do this mod after some other MV and this mod is the best. You will be happy.
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Hi Mega,
Longtime no posts from me. There is another alternative to MV. I built a custom amp for a regional performer who wanted tone and gain but no insane stage volume. He felt MV (A la Boogie) was "buzzy". I ended up adding an attenuator to the back end of the amp. I really had to because the amp was designed to drive four 6V6 power tubes into distortion but it was very clean out of the pre-amp even diming the gain. It nailed the sound he was looking for, without causing an earthquake. I used two stages which gave him: full power- great for outdoor venues, one stage for large indoor gigs, and second stage for small places. Control for it is on the front panel. ON-OFF-ON toggle. There is a small boost for the pre-amp now, but it does dirty it up a bit in front. Amp has been in service one year this October. Cheers, Larry
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Hi Mega,
Longtime no posts from me. There is another alternative to MV. I built a custom amp for a regional performer who wanted tone and gain but no insane stage volume. He felt MV (A la Boogie) was "buzzy". I ended up adding an attenuator to the back end of the amp. I really had to because the amp was designed to drive four 6V6 power tubes into distortion but it was very clean out of the pre-amp even diming the gain. It nailed the sound he was looking for, without causing an earthquake. I used two stages which gave him: full power- great for outdoor venues, one stage for large indoor gigs, and second stage for small places. Control for it is on the front panel. ON-OFF-ON toggle. There is a small boost for the pre-amp now, but it does dirty it up a bit in front. Amp has been in service one year this October. Cheers, Larry
Seems like a similar train of thought as using Da_Geezers cathode bias attenuator
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Nice schematic Thermionic but is not for the kind of amp of Megachunk wich is a fixed bias
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Nice schematic Thermionic but is not for the kind of amp of Megachunk wich is a fixed bias
Hi Stratele52- Not my schematic. I pad down the signal at the output of the OT. Should work fine for either fixed or cathode bias. I didn't post a schematic because I consider the rig proprietary and I haven't applied for the patent yet. (I'm not sure if it is different enough to impress the patent office folks but there are a few new wrinkles in the design I have not seen elsewhere.)
Regards, Larry
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Hey guys.
That power cut feature/layout looks very appealling to me. I would be interested in installing that. But I digress...
I installed that master volume and it sounds awesome. I really like it. Best this amp has ever sounded. Can't wait to gig with it. Going to put it in a combo soon. Now with that master setup, can I still put in what's in that layout as a power cut? Even with my fixed bias? Really like to run both if possible.
I will post my voltages and an updated schematic of the new amp soon. It sounds a little bassy, but I did alter a few values for close ones in either direction. I finally got the bass control reacting as I wanted. Thanks for all the help, guys.
Megachunk
Mike G
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can I still put in what's in that layout as a power cut? Even with my fixed bias? Really like to run both if possible.
No. Geezer's circuit is for cathode biased amps only.
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Is there something similar that would work for my set up?
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Is there something similar that would work for my set up?
I'm not aware of anything similar. You could always try VVR or a power attenuator between the amp and the speaker.