Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: macula56 on June 15, 2011, 08:27:31 am
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I want to boost the volume in an amp. I'm trying to find a schematic that would point me in that direction. Something with perhaps 1/2 a 12AX7 into a volume control then into the other half of the 12AX7 and then into a CF then tone control. Can anyone point me to a good schematic? I see lots with standard Fender style stuff and Marshall style. I haven't had any luck with this type as far as schematics. Thanks, JMac.
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Try this:
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having zero experience with the cascode stuff, what are the benefits of these circuits? are they better than plate fed into the next stage?
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They don't have huge gain,which may be too much when you just want a volume boost.
Also take a look at Mesa's Solo circuit on the Lonestar amps.they use the effects loop to add a solo boost to the amp.
there are other ways to just add a 'boost' in volume at lower amp settings without adding too much gain.Try a .05uf across the existing volume pot.It does add gain but not necessarily distortion depending on your amp.
Then you can have a negative feedback lift switch.
It depends on what you want happening with the volume you seek.Sometimes a good EQ pedal in front of your amp gives you what you need without the added circuitry.
Lots of options.
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i thought about adding an extra stage like some of the Bassman's. i just want a little volume boost. thanks Psycho.
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how about a simle tone stack defeat boost. using a vactrol etc? I love that type of boost it seems to be the perfect bump for whatever level im playing at.
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So Jerry do you have an example of a tonestack defeat switch we could look at or directions to were we could see it on an amp schematic.
Thanks Bill
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the tone defeat is not what i am looking for but thanks Jerry.
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what about two volumes or two master volumes. or is it that you also want a little gain boost?
for tone junkie its just removing the tone stack ref to ground off the mid pot. you can use a mechanical switch (front panel) or if you know how to wire up a vactrol or relay, you just add or subtract the ground to the tone network.
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The problem w/ a tone stack lift is that the signal easily gets muddy from too much bass especially at high volumes. So you have to account for that w/ a smaller coupling cap from the prior stage and/or a small bypass cap also. Or you can make a simple high pass filter network or similar. Then it will sound good and be useful/practical.
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So if you use the tone stack lift you need to dial in a way to take out the extra bass with the other side of the switch. possibly adding a gain stage with just enough boost for the lead channel might be a better way to go.
Thanks Bill
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We're getting away from my original question folks. I am not looking for a solo boost or anything to do with lifting the tone control ground. i am looking for a schematic that has a overall volume boost after a volume control and before the tone controls. if anyone can point me to a schematic like that i would greatly appreciate it.
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Here's a simple but effective boost. Replace the 470K with a pot if you want a boost level also.
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i am looking for a schematic that has a overall volume boost after a volume control and before the tone controls. if anyone can point me to a schematic like that i would greatly appreciate it.
If you are willing to expand your approach ................... you can get a volume boost with these. Also with Geezer's Tweed Overdrive Special, he used a 12AX7 triode for a "FAT" control that does increase the volume. It's in the SCH library.
You can also use a SPDT to switch in a lower value 12AX7 cathode resistor with a high value cathode cap. In the schematics file there is a "Switches, bells and whistles" thread with numerous ideas.
http://www.el34world.com/Forum/index.php?topic=5621.0 (http://www.el34world.com/Forum/index.php?topic=5621.0)
With respect, Tubenit
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many thanks Sluckey and Tubenit. i will try these ideas when i get home.
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dual volume's or masters, similar to that switch bypassing the 470k res .
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The trim boost on the blusemiester is a good one here is another .
Bill
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Sorry the picture didnt work well I will fix this when i get back home.Bill
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macula56 I know these were not what you were asking for i couldnt find anything like that in just a plain control but here is solo boost that if not helping you might help someone else.
thanks Bill