Marshall JVM410HJS with a Lar-Mar PPIMV, Post Phase Inverter Master Volume with a Gibson Les Paul Custom R7 and a 1971 Marshall 1960A 4x12 with Pulsonic Greenbacks.
This is an older video, but I think what we might also be hearing is the impact of lower NFB to the preamp when turning down the output. That compounding with the impact of not driving the speakers is why we're hearing the fizzier gain (lower NFB not suppressing the gain as much). It might be interesting to see how adding an adjustable NFB along with a PPIMV would sound
Its also clearly goes in to blocking distortion at the lower settings. Depends on the amp but I've had great success with one of these and even the crossline (straight off the power tube plates). My AB763 twin reverb has a definite sub 100db sweet spot, narrow as a gnat's nadgers, but its there. I think it works well tbh given the ease of modification and the relative inexpense. Of course these days we've got stuff like the UA Ox and almost nobody gives a fig about keeping it analogue. Which is a shame but that's the truth.
Does the ppimv typically remove the presence control from the circuit (render the presence control useless) ….due to changing of the negative feedback change ?
What everyone needs to appreciate is 120db is rock concert sound level and 70db is quieter than a vacuum cleaner. For every 10db difference it is 10 x more powerful wattage wise, so for example if 1 watt gets you 70db output then you would need 100,000 watts to get you to 120db. Also a 10db increase will sound twice as loud, so a 50db increase will sound twice as loud, 5 times. Not sure why anyone would expect a similar bass or punch amount at the lower level.
A great demonstration as always. I think what a lot of people perceive as compression is due to the variance in negative feedback as the master volume is reduced, the damping factor will change and more highs and less mids will be heard, as there is less output being fed back to the inverting side of the driver tube. Great to hear your sinuous bends on a Monday evening sir. All the best from Wales as ever
Thanks PoJoWo, it makes sense. And if the PI is not too overdriven the influence from the NFB loop would still be at work to some extent when the PPIMV is set to a higher volume. I can add that the amp was set at 2 gainstages, JTM 45-ish preamp circuit with volume (gain) at 8, crunch channel volume maxed, master maxed, 16 Ohm/27k NFB and B+ voltage at power tubes c:a 415V. Presence 5, Resonance 8.
Mats Frånlund awesome Thankyou for the extra information! I think for the reasons we mention the jtm45 feedback arrangement provides that extra amount useful at lower master settings, good choice! Amps such as the 2203 and seventies 4 Ohm/100k arrangement already sail close to the wind in this respect for me when it comes to lower volume situations.
Hmm... Thinking that a Tiny Terror kind of tone control before the power tubes could be very useful to dial out fizz when PPIMV is set bedroom low and/or when PI is very distorted. In both cases the NFB loop will be practically not working. Am I on the right track here?
Great video, Johan! I've got a Wizard Vintage Classic, which has got a PPIMV as well. The explanation at the end just describes the way it works perfectly. Turning it down will make the amp very brittle and lose some low end. It's still useable at home and sounds good, but (of course) sounds better when you turn the PPIMV up a little bit.
It sounds like crap even if you turn up PPIMV on half. It's better set MV at 1 then use this piece of sh.t with a lot of loosing in tone. Attenuator is the way to go.
Great video, as always Johan. Depending on the design of the PPIMV, it can actually change the break frequency of the high-pass filter between the PI and the output valves, reducing the low end either a little or a lot, depending on parts values. The explanation at the end is spot on, too. Sometimes, there's just no substitute for ear- (and mic-) punishing SPL. ;)
Hi Gregory! A thought was planted into my head the other day... So this weekend I'm gonna stick an AC30/Tiny Terror-kinda tone control after the PPIMV, to see if it's possible to dial out the high mid and treble fizz at low volume PPIMV setting.
It awns´t that bad actually, of course nothing like unleashing the marshal beast at 120db :) Thank you for making these videos Johan, yours are IMHO the best and most informative
Kazuki Yoshida his room mic was too far from sound source\cab\his ears. Lol! Waiting for remake of video. Currently looks like attenutor products advertisement.
Great video, as always. I have to agree with the comments by Mats. it's a lot to do with how much the speaker is being worked. I have a 2150 with a PPIMV and find that if the master volume is below 4, it sounds bit dead and fuzzy. But get it above 4 it comes alive and more open sounding. I guess it's the compromise when playing high wattage amps at levels were you don't piss off the neighbors! Just a thought. Do you think a open vs a closed back speaker cabinet would make that much difference?
+Kevin Allen Thanks, whether it's open or closed also influences bass response and spatial richness of the tone. So there are a bunch of parameters to play with here.
I agree with Mats, to me it sounds like cabinet response or even mic compression at 120dB. It's that same body that's lost when going from 100 watts down to 50. iggrut, a PPMIV should have roughly the same circuit values as a stock non-master volume amp when cranked, so not switchable but stock value at full volume.
Hi Erik! You're right, fully cranked the two PI outputs sees roughly 200k each to audio ground through the bias circuit smoothing capacitors. Original values was 220k each.
Somehow i like it the most at 110db :) got an awesome sound. I have a Marshall JVM myself (standart without mods) Can you mod it with without loosing the original sound? So switchable? Greets
i've got stock ppimv in marshall studio 15 and I can attest that there is no bass/punch at bedroom volumes... i'd love to hear ppimv and attenuator comparison at equal dB.
+bas broeders this means that the pream tubes and the phase inverter tubes work hard. As opposed to a standard Master Volume where only the preamp tubes work hard.
I'm wondering should I have my tech use the 2nd speaker out or let him drill another hole in the chassis for the pot? Easy reversibility vs more flexibility, what do you guys think?
This kind of attenuation not sound as good as power brake/attenuator. Does it sound fizzy In live situation, likewise on this clip? Have you ever played on amp with VVR (Variable Voltage Regulator)?
I've been amazed at how many useful tones you've achieved using everything from rare and expensive vintage equipment to inexpensive and new equipment. You could become Marshall Amplification's Public Enemy Number 1! haha.
Attenuator would be much better. i have Two-notes Torpedo Reload, and this thing is just amazing. Aracom Pro is the best attenuator, but it costs allot. About 850$ i think, but it's worth it.
Peaking acoustic sound of strings may affect volume normalization. Test with room mike in giant reverby place wasn't a good idea. No isolated sm57 test - no idea about performance for headphones users and in mix with reverb in post\amp loop. Gnr recorded apetite using sm57 with reverb in post. And I have very bad feeling about too far from cab room mike position that lost all bass frequencies. Room mike needs to be placed near the head\ears of tester to have correct level of bass frequencies. This video feels like promotion for loadbox makers. Also no bass setting compensation for increased speaker membrane movement demonstrated. And obvious stuff like room mike needs too be factory new 20hz to 20khz colorless human ears type. Dual capsule rode stereo video microphone or ixy meets specs perfectly. Remake needed so much!
I wonder how much money Mats charges for these PPIMV mods, since they cost less than 5$ in parts. Its literally a stereo potentiometer, 5 wires and two resistors.
Yeah, the parts for a PPIMV mod is cheap:-) The use of my name was for the whole shebang of mods I have implemented on this particular amp, my mod testbench for over a year now. At the moment it's got 20 mods and 10 of them are on switches.
Mats Frånlund test with room mike in reverby place wasn't a good idea. No isolated sm57 test - no idea about performance for headphones users and in mix with reverb in post\amp loop. And I have very bad feeling about too far from cab room mike position that lost all bass frequencies. Room mike needs to be placed near the head\ears of tester to have correct level of bass frequencies. This video feels like promotion for loadbox makers. Also no bass setting compensation for increased speaker movement demonstrated. And obvious stuff like room mike needs too be factory new 20hz to 20khz colorless human ears type. Dual capsule rode stereo video microphone or ixy meets specs perfectly.
+aijb That was in SPL, if you wanna convert dB SPL into dB HL there are curves you can use, you know upper mids are easier to hear than extreme lows and highs. Cheers
i barely hear a difference....but do this mod to a fender twin reverb and you got a new super lead killer amp...... i had Hal at Guitronics in san francisco do this mod on my 73 quad reverb n wow..... today i am taking in my 72 twin 2x12 combo for the same thing....... SF twins do not get alot of respect but that would change if u did this..... try it..... ( btw, why would u want to do this mod to a marshall? seems cat chasing tail..... w/ a all clean tube amp like a twin it makes sense... to me anyways :)
that amp is to bright,, joe satrionni made it better, but if any amp did not need a ppmv that is it,, it had good master vol and a lot of gain, put one on a 87x, that amp loves them
I installed the Lar/Mar PPIMV on my 1987x, very easy mod and I Love it, best MV out there! Love your videos Johan, Hello from Los Angeles.
+brian buckner Glad to hear it! Cheers from Gothenburg Sweden!
This is an older video, but I think what we might also be hearing is the impact of lower NFB to the preamp when turning down the output. That compounding with the impact of not driving the speakers is why we're hearing the fizzier gain (lower NFB not suppressing the gain as much). It might be interesting to see how adding an adjustable NFB along with a PPIMV would sound
Its also clearly goes in to blocking distortion at the lower settings. Depends on the amp but I've had great success with one of these and even the crossline (straight off the power tube plates). My AB763 twin reverb has a definite sub 100db sweet spot, narrow as a gnat's nadgers, but its there. I think it works well tbh given the ease of modification and the relative inexpense. Of course these days we've got stuff like the UA Ox and almost nobody gives a fig about keeping it analogue. Which is a shame but that's the truth.
Does the ppimv typically remove the presence control from the circuit (render the presence control useless) ….due to changing of the negative feedback change ?
What everyone needs to appreciate is 120db is rock concert sound level and 70db is quieter than a vacuum cleaner.
For every 10db difference it is 10 x more powerful wattage wise, so for example if 1 watt gets you 70db output then you would need 100,000 watts to get you to 120db. Also a 10db increase will sound twice as loud, so a 50db increase will sound twice as loud, 5 times. Not sure why anyone would expect a similar bass or punch amount at the lower level.
A great demonstration as always. I think what a lot of people perceive as compression is due to the variance in negative feedback as the master volume is reduced, the damping factor will change and more highs and less mids will be heard, as there is less output being fed back to the inverting side of the driver tube. Great to hear your sinuous bends on a Monday evening sir. All the best from Wales as ever
+PoJoWo Thanks man, Cheers!
Thanks PoJoWo, it makes sense. And if the PI is not too overdriven the influence from the NFB loop would still be at work to some extent when the PPIMV is set to a higher volume. I can add that the amp was set at 2 gainstages, JTM 45-ish preamp circuit with volume (gain) at 8, crunch channel volume maxed, master maxed, 16 Ohm/27k NFB and B+ voltage at power tubes c:a 415V. Presence 5, Resonance 8.
Mats Frånlund awesome Thankyou for the extra information! I think for the reasons we mention the jtm45 feedback arrangement provides that extra amount useful at lower master settings, good choice! Amps such as the 2203 and seventies 4 Ohm/100k arrangement already sail close to the wind in this respect for me when it comes to lower volume situations.
Hmm... Thinking that a Tiny Terror kind of tone control before the power tubes could be very useful to dial out fizz when PPIMV is set bedroom low and/or when PI is very distorted. In both cases the NFB loop will be practically not working. Am I on the right track here?
Mats Frånlund I would say so.. You mean a vox style tone cut across the two sides of the p.i.? Very effective in these situations indeed
WOW THE BASS END SEEMS TO DISAPPEAR WHEN THE DB'S ARE DROPED, ANOTHER GREAT VIDEO! I'VE BEEN LEARNING A LOT FROM THESE VIDEOS
+MB215 Thanks, glad to hear that!
MB215 room mic was too far from cab! Invalid test.
Great video, Johan! I've got a Wizard Vintage Classic, which has got a PPIMV as well. The explanation at the end just describes the way it works perfectly. Turning it down will make the amp very brittle and lose some low end. It's still useable at home and sounds good, but (of course) sounds better when you turn the PPIMV up a little bit.
+BudMovies Thanks man
It sounds like crap even if you turn up PPIMV on half. It's better set MV at 1 then use this piece of sh.t with a lot of loosing in tone. Attenuator is the way to go.
Great video, as always Johan. Depending on the design of the PPIMV, it can actually change the break frequency of the high-pass filter between the PI and the output valves, reducing the low end either a little or a lot, depending on parts values. The explanation at the end is spot on, too. Sometimes, there's just no substitute for ear- (and mic-) punishing SPL. ;)
+Gregory Pease Thanks man
Hi Gregory! A thought was planted into my head the other day... So this weekend I'm gonna stick an AC30/Tiny Terror-kinda tone control after the PPIMV, to see if it's possible to dial out the high mid and treble fizz at low volume PPIMV setting.
Interesting how the sound gets fizzy and thinner as you turn down, awesome video!
+Tim Raybould Thanks man!
another great and valuable video...... thanks Johan.
+PureToneAmps Thanks man!
It awns´t that bad actually, of course nothing like unleashing the marshal beast at 120db :)
Thank you for making these videos Johan, yours are IMHO the best and most informative
+Kazuki Yoshida Thanks, glad to hear it! Cheers Johan
Kazuki Yoshida his room mic was too far from sound source\cab\his ears. Lol! Waiting for remake of video. Currently looks like attenutor products advertisement.
It sounded thinner on lower settings. They still sounded good, just different
+Lars Sig Thanks Lars!
Thank's again Johan.
+V8punch Cheers
Lar-Mar (trainwreck type 2) is by far the best master volume for non master marshalls, and most amps.
Great video, as always. I have to agree with the comments by Mats. it's a lot to do with how much the speaker is being worked. I have a 2150 with a PPIMV and find that if the master volume is below 4, it sounds bit dead and fuzzy. But get it above 4 it comes alive and more open sounding. I guess it's the compromise when playing high wattage amps at levels were you don't piss off the neighbors!
Just a thought. Do you think a open vs a closed back speaker cabinet would make that much difference?
+Kevin Allen Thanks, whether it's open or closed also influences bass response and spatial richness of the tone. So there are a bunch of parameters to play with here.
Another great video ;-) I'm curious , how much of low-end can be added with tone correction, to reduce low-end roll-off phenomena.
+Maciej Toliński Thanks! That would be an interesting id a for a clip! Cheers
I agree with Mats, to me it sounds like cabinet response or even mic compression at 120dB. It's that same body that's lost when going from 100 watts down to 50. iggrut, a PPMIV should have roughly the same circuit values as a stock non-master volume amp when cranked, so not switchable but stock value at full volume.
+Erik Ross Thanks Erik, yeah on max it should be bypassed
Hi Erik! You're right, fully cranked the two PI outputs sees roughly 200k each to audio ground through the bias circuit smoothing capacitors. Original values was 220k each.
Thought the 110 and 103db sounded best. Great vid!
+pppaulie73 Thanks!
I felt like I was watching Vincent Price
Love the intro
+Elias Levinson hahaha, yeah a talking beard basically :-)
I believe I prefer pre phase inverter master volumes myself. Nice demo.
This amp seems to lack that mid range "strength" typical to its predecessors. I'm not a fan, but beyond 103 it's very nasal.
Love your work Johan!
+Chris Mitlyng Thanks Chris! Glad to hear it :-)
Somehow i like it the most at 110db :) got an awesome sound.
I have a Marshall JVM myself (standart without mods)
Can you mod it with without loosing the original sound?
So switchable?
Greets
Thanks, that depends on the mod, some mods can be bypassed
i've got stock ppimv in marshall studio 15 and I can attest that there is no bass/punch at bedroom volumes...
i'd love to hear ppimv and attenuator comparison at equal dB.
+Michał Pachocki That's a great idea man, consider it done :-)
Johan Segeborn great!
ive been searching for a vid comparing ppimv vs attenuated Marshall.... PLEASE HELP
i guess my neighbours won't approve the result of that video.
+Da Faq hahaha, sorry about that :-)
I read that 120 db is the sound level of a turbofan airliner taking off, from only 100 feet away.
+Tom Baer :-) yeah the ear defenders are pretty good to have here ;-)
If you build this in like a plexi does this mean the tubes are working hard but you can turn down?
+bas broeders this means that the pream tubes and the phase inverter tubes work hard. As opposed to a standard Master Volume where only the preamp tubes work hard.
Oh i see. Thanks and keep making video's!
+bas broeders it will be my pleasure! :-)
I'm wondering should I have my tech use the 2nd speaker out or let him drill another hole in the chassis for the pot? Easy reversibility vs more flexibility, what do you guys think?
Johan, would you consider installing a PPIMV a better solution to using an attenuator in terms of keeping the sound as much as "intact" as possible?
+SOMEBODY I'm actually using attenuators myself
This kind of attenuation not sound as good as power brake/attenuator. Does it sound fizzy In live situation, likewise on this clip? Have you ever played on amp with VVR (Variable Voltage Regulator)?
What PPIMV do you recommend that is the easiest to convert back to the original specs and retains the tone at various attenuation?
I bet the lower settings would be great in a mix, but they do sound rather weak alone.
+Rick McCargar Thanks man, yeah in a mix the additional low end from the volume probably needs to be cut anyway
I've been amazed at how many useful tones you've achieved using everything from rare and expensive vintage equipment to inexpensive and new equipment. You could become Marshall Amplification's Public Enemy Number 1! haha.
Johan, would you consider this mod to be the most transparent or an attenuator would be better?
Attenuator would be much better. i have Two-notes Torpedo Reload, and this thing is just amazing.
Aracom Pro is the best attenuator, but it costs allot. About 850$ i think, but it's worth it.
So, whats your opinion between PPIMV vs attenuator? I use the ultimate attenuator.. and its sounds allright by me. Is PPIMV a thing to consider?
Marshall 1987x 2013 reissue through a 1960bhw
+Manz4n It can be effective combine them
+Manz4n Personally I have no PPIMV on the 1987X, I'm using a Weber MASS or a Hotplate.
Thanks for the feedback, great video as always Johan.
+Manz4n Thanks man!
The more loaded fazoinvertor,the less effective presence.
+Максон Максон Feel free to elaborate! Cheers Johan
When you're using a PPIMV for bedroom volume level ,stops working "presence" on your amp.It's not very nice.
+Максон Максон Would you say that you get that effect on full volume as well? With a PPIMV.
Peaking acoustic sound of strings may affect volume normalization. Test with room mike in giant reverby place wasn't a good idea. No isolated sm57 test - no idea about performance for headphones users and in mix with reverb in post\amp loop. Gnr recorded apetite using sm57 with reverb in post. And I have very bad feeling about too far from cab room mike position that lost all bass frequencies. Room mike needs to be placed near the head\ears of tester to have correct level of bass frequencies. This video feels like promotion for loadbox makers. Also no bass setting compensation for increased speaker membrane movement demonstrated. And obvious stuff like room mike needs too be factory new 20hz to 20khz colorless human ears type. Dual capsule rode stereo video microphone or ixy meets specs perfectly. Remake needed so much!
Make your own then. Sheesh.
I wonder how much money Mats charges for these PPIMV mods, since they cost less than 5$ in parts. Its literally a stereo potentiometer, 5 wires and two resistors.
+John Doe haha, I'm pretty sure he doesn't take any such jobs, it's just a part of the mod on that amp.
Yeah, the parts for a PPIMV mod is cheap:-) The use of my name was for the whole shebang of mods I have implemented on this particular amp, my mod testbench for over a year now. At the moment it's got 20 mods and 10 of them are on switches.
Ah I see. I noticed the choke and all the switches on the top of the chassis, very cool!
Thanks! The choke is no mod though, it's stock on the HJS version.
Mats Frånlund test with room mike in reverby place wasn't a good idea. No isolated sm57 test - no idea about performance for headphones users and in mix with reverb in post\amp loop. And I have very bad feeling about too far from cab room mike position that lost all bass frequencies. Room mike needs to be placed near the head\ears of tester to have correct level of bass frequencies. This video feels like promotion for loadbox makers. Also no bass setting compensation for increased speaker movement demonstrated. And obvious stuff like room mike needs too be factory new 20hz to 20khz colorless human ears type. Dual capsule rode stereo video microphone or ixy meets specs perfectly.
what was this measured in? SPL or HL?
+aijb That was in SPL, if you wanna convert dB SPL into dB HL there are curves you can use, you know upper mids are easier to hear than extreme lows and highs. Cheers
i barely hear a difference....but do this mod to a fender twin reverb and you got a new super lead killer amp...... i had Hal at Guitronics in san francisco do this mod on my 73 quad reverb n wow..... today i am taking in my 72 twin 2x12 combo for the same thing....... SF twins do not get alot of respect but that would change if u did this..... try it..... ( btw, why would u want to do this mod to a marshall? seems cat chasing tail..... w/ a all clean tube amp like a twin it makes sense... to me anyways :)
that amp is to bright,, joe satrionni made it better, but if any amp did not need a ppmv that is it,, it had good master vol and a lot of gain, put one on a 87x, that amp loves them
Room mic is too far from sound source! Not funny.