best master volume

Discussion in 'Amp Tech Center' started by Mongo Park, Jan 17, 2019.

  1. Mongo Park

    Mongo Park Tele-Holic

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    I am wondering which amp you have experienced that has a nice master vol. I have tried the pre and post PI master volume on the 5E3. For me both seem to suck the tone out of the amp when I turn it down to a house vol. . I was going to try it on the 6G2 but think it would be much the same thing. It may be the nature of the master vol for these amps since it is not a stock function. The orange tiny terror seems to do it better, but I can not understand what makes it function better, I don't own one manybe it is much the same. Any insights into master volumes would be appreciated.
    Maybe a pentode/triode pot would work better, or would it work better on cathode follower amps.
    http://www.prowessamplifiers.com/schematics/images/tiny_terror.pdf
    [​IMG]

    Cheers Ron.
     
  2. Nickfl

    Nickfl Tele-Afflicted

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    A post pi master volume on LTP amps seems to work better than any master volume on a cathodyne phase inverter. To me the pre pi MV on a cathodyne makes the most sense, but I tend to keep them turned up most or all of the way on the amps that have them. On the other hand, I've got a Dumble based build with a PPIMV that I find very usable.

    At the end of the day I think it has more to do with the preamp design than anything else. A 5E3 gets a lot of its sound from pushing the power tubes, while my Dumble clone is all about the preamp distortion... I bet that Orange is more like the Dumble than the 5e3 in that way.
     
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  3. gusfinley

    gusfinley Tele-Holic

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    If you were to bridge the capacitor of the tone control on the tiny terror you will get a Vox/Matchless-style "Crossphase" Master Volume. This is also, of course, a post-phase-inverter and only affects the signal going to the power tubes by varying the amount of destructive interference (cancellation) between the phases.
     
  4. telemnemonics

    telemnemonics Doctor of Teleocity

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    Depends on what you expect from it.
    The reason amps designed around a MV sound better with the MV turned down is not the MV itself, it's the extra gain stages in the preamp creating distortion before the power amp.

    The 5e3 and 6g2 don't have preamp distortion to amplify with the turned down clean power section, and get their magic from the power section distorting, or more accurately the whole amp distorting.
    You can ge a little more dirt from them but they will never do the Tiny Terror higher gain preamp distortion thing you get from amps designed around preamp distortion and a MV to control the output volume.

    IMO no matter how nice the MV is, it can't do a whole lot without preamp distortion.
     
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  5. Nickfl

    Nickfl Tele-Afflicted

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    RE: the pentode/triode control, the only amp I've put one of those on is my most recent build and I used it on a preamp pentode as a valve wizard style morph control, so a bit different than what you're asking, but I like it alot on that so far.

    The only other one I've ever experienced was on a Peavey Windsor, which I believe had a similar morph control on the power tubes. It certainly had a noticeable effect but not one I especially liked. Overall that amp didn't do much for me though, so I can't really judge from that experience.
     
  6. schmee

    schmee Friend of Leo's

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    I have tried 3 of the 4 common MV schemes and they ALL suck the tone. You really shouldn't need one for a 5E3.
     
  7. rze99

    rze99 Poster Extraordinaire

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    I use an attenuator with my 5e3 and am happy with that as the solution to the gain tone db level conundrum.
     
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  8. robrob

    robrob Poster Extraordinaire Ad Free Member

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    From my website:
    https://robrobinette.com/5F6A_Modifications.htm#Frondelli_Master_Volume

    Frondelli Master Volume

    If you are building a 5F6A then I recommend installing the Frondelli Post Phase Inverter Master Volume. This is my favorite master volume for several reasons:

    The power tube grid leak resistance does not change when the master volume is adjusted which keeps the bias voltage from changing.

    No fail safe resistors are needed on the wiper like on the Type-2/Lar-Mar master volume because the wiper is used for signal input, not output to the power tubes. Bias voltage will not be interrupted if the pot wiper fails.

    The Frondelli master volume simply replaces the grid leak resistors with a dual-gang audio pot (one shaft turns two pots). For amps with 220k grid leaks use a 250k pot and for amps with 100k grid leaks use a 100k pot.

    With the master volume set to maximum the power amp circuit is just like factory. There's no added coupling capacitors to change the amp's voicing.

    [​IMG]

    [​IMG]
     
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  9. Luthier Vandros

    Luthier Vandros Tele-Meister Silver Supporter

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    I implemented the Frondelli (IIRC) PPIMV on a blackface clone I built and it's spectacular!
     
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  10. bftfender

    bftfender Friend of Leo's

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    New Marshall DSL40cr, MV is the best i ever used,gain can be set up from clean to 3 more stages of gain with footswitch and button switch on amp and Resonance & presence gets the room dialed in quick. It retains the tone from barely on to dimed. Character holds and you really can have clean..mild crunch..big crunch and then leads pop with old school and a tinge of modern if needed
     
  11. Snfoilhat

    Snfoilhat Tele-Holic

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    I can't find a schematic for the DSL40CR anywhere -- I think it is too new and Marshall is holding onto it for the time being. I'm curious to see how they worked the master volume controls.

    I think all the PPIMVs I have heard have been OK but no better than OK. Like so much in gear, it's not a limitation in the technology or your access through these helpful folks to good information, but in your personal definitions of 'house volume' and good tone.

    I'm with @telemnemonics that a vintage style amp with a very basic preamp is probably a poor candidate for any master volume because the desirable character of the amp is probably a product of the speaker-OT-power amp side of the circuit. The 5E3 and 6G2 are legends, but they are also something like cheap phonograph preamps when you take half the circuit out. I don't see any mojo in there. But what do I know -- come to think of it, there's at least one $$$ boutique pedal that claims to be a transitorized 5E3 preamp.

    FWIW I went down a different road w/ my amps of the last couple years, trying to get as much enjoyment out of the preamps as possible because even a 5W single-ended 6V6 type amp is not something I want to hear at overdrive volume more than maybe once a week.

    Come to think of it, if a person really loves a Fender circuit, and nothing else will satisfy, then I wonder if all the messing around with the chassis and the speakers and attenuators is misguided, and instead if these threads should be about inexpensive DIY iso boxes or even just baffles? Bogos? Is there such thing as a partial isolation box?
     
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  12. bftfender

    bftfender Friend of Leo's

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    i think what worked for me is..and i have PTP jmp50 (with ppimv trainwreck 3 wich makes that amp also very playable at any volume&.6100..it that the DSL40cr..the tone is very consistent..once you set the amp up..now i always dime the channel Volume..then the Master basically allows me to bring to level of need...of course ..the louder the fuller-- typical marshall) but the tone shaping is retained pretty much with MV..just being that..a master Volume
     
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  13. telemnemonics

    telemnemonics Doctor of Teleocity

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    I've been meaning to set up a 3x12 iso cab under blankets in the basement for years, but never got around to it.
    Figuring I'd run the wire up and plug it in to an amp along with a 1x12 of suitable impedance, so only 25% of the speakers would be heard.
    Wouldn't have to be a 3x12 but since I've got a couple of 4x12 cabs and lots of speakers I could set it up for even speaker distribution and it would cost nothing.

    I have a few vintage low gain amps with modern MV added, and had one of the first pre JCM800 MV Marshalls. Didn't like any of them or even the later JCM800s much, but in 2001 I tried one of the new Orange AD30s that were arriving in the US, and it was both the first MV amp I liked and the first amp I bought new at full price, which was $1100, the most I've paid for an amp.
    I now prefer the OR15 I got a couple of years ago.

    The 18w Marshall TMB clone with MV sounds fine with the MV dimed, but turn it down for more dirt and it just sort of makes it mushy, no cranked screaming Marshall sounds.
    The OR15 OTOH can get cranked Marshall sounds at well below distorted Champ volume if set for 7w, and sounds better at 15w but not as low volume.
    It's partly based on the Tiny Terror, which has to be derivative of the fine older AD30 preamp that put Orange back on the map.

    When I was considering an AD30 I played them weekly at a local shop, and also listened to another player who would bring in his Marshall JTM45 RI to compare, he did this numerous times to make sure he really liked the AD30 better and finally traded in and bought the new Orange.

    Not saying Orange owns the market on preamp distortion, I just seem to like them better than the modern Marshall high gain amps I've tried, though still not as much as the Plexi and early metal panel non master Marshalls I used to own.
    But given the cost, volume issues and weight of a Plexi 100, I'm pretty happy with the little 15w Orange!
    Or an 18w TMB pushed by a Tone Bender...
     
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  14. telemnemonics

    telemnemonics Doctor of Teleocity

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    I forgot to mention that among Marshalls with PPIMV added quite a few got some sort of gain mod in the preamp to get more useful range out of the MV knob.
    The first Marshalls with MV of course got the two channels that were previously parallel run in series, for a very primitive higher gain preamp distortion design that required almost nothing added, but lost the other inputs.

    Of the dozen or so non master 50s and 100s I've owned I found some to be clean all the way up to 10 while others were all snarling dirt from 2 on up.
    So if you put a PPIMV on one of the really dirty samples it would be more useful than on the really clean ones.

    Seems like the early Plexis had power sections that distorted easily, then around the last plexi/ first metal panel the power section got beefed up while the preamp didn't get more gain, so they were just brutally loud punchy bright amps but not very dirty unless modded a bit.
    By '71 they were back to the nasty, but all the '69 and '70 models I owned were clean and bright ear breakers. (with single coils)
    I suspect most of those have been modded a little by now, and given the liberties taken in production specs and parts I suspect it's hard to tell if they are totally stock.
     
  15. Snfoilhat

    Snfoilhat Tele-Holic

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    This is the issue, I think. If you just insert a control into the power amp of some existing design, and that control is some simple, passive component like a potentiometer or variable resistor, it's not going to be just a master volume. It can't help but interact with the stuff around it. Some of them will form ___-pass filters with the coupling capacitors and change the EQ. I think some others will load down the phase inverter, changing how it operates. Sometimes everything is pretty close to workable but the taper kinda sucks, because neither linear nor audio/log is quite right. Toward the bottom (lowest volume settings), the resistances to ground are so small (especially w/ audio taper) that the circuit can behave very strangely. Turn it up out of the awkward zone, and in my (limited!) experience you are immediately at 50%+ of total volume. Which can still be pretty useful, but maybe wakes the baby.
     
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  16. Mongo Park

    Mongo Park Tele-Holic

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    Thanks Rob and all of you who took the time to answer my question. I think it boils down to I need more preamp distortion to make this work better as a start.

    Cheers Ron
     
  17. robrob

    robrob Poster Extraordinaire Ad Free Member

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    A clean boost pedal + MV can do a lot of good.
     
  18. rolloman

    rolloman Tele-Holic

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  19. BobbyZ

    BobbyZ Doctor of Teleocity

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    Since you're talking Deluxe I'll tell you what I use in my DR, a Maverick. Speaker dialed back I can crank the amp up to get my Gibsons grinding, without blowing out windows.
    However even at the lowest 90 or 91 db setting, crank up a Deluxe and it's still pretty loud, not apartment volume.
    So if ultra low volume is your end game a Maverick is just a step in that direction.
    Want a Fender amp with a decent MV, look at Pro Sonic or Mesa and figure out how they did it. Pretty sure it's a bit more complicated than a 3 dollar pot.
    Fender went the 3 dollar pot rout in the 70s, yeah those were great. :)
     
  20. rolloman

    rolloman Tele-Holic

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    Yeah, but London Power uses a ganged pot. $6. Has anyone figured those other two amps just mentioned. That would be an interesting project. Is the MV solid state or passive.
     
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