Hoffman 6 v 6 Plexi W/ Lar Mar MV

[purpletele]

Here are the photos as previously posted, as well as a link to a video of the High Gain Tone.

[Glenn]

Nice build. Sounds great.
What is the purpose of the 2 micas on the MV pot?
I was looking at the schematic and didn’t see them.
Are they smoothing caps of some sort?
Thanks

[purpletele]

Nice build. Sounds great.
What is the purpose of the 2 micas on the MV pot?
I was looking at the schematic and didn’t see them.
Are they smoothing caps of some sort?
Thanks

I use those to bring out the highs that get lost in the MV equation.  Seems to work well

[purpletele]

Update on the Plexi Mod 5

I liked the high gain of the Mod 5, but not all of the time, and I lost the nice Plexi Cleans so I un-modded my 6V6 Plexi.


I left the MV which worked great, however I lost alot of volume with the MV.  I can dime everything and it sounds pure, but it's not loud enough to play with a strong drummer.

Notes and Question


1. I am using a 250K Dual gang Pot for the MV.  I have a 2.2 M resistor on each of the wipers of the Pots.


2. Everything else has been brought back to the original specs.


3. Can anyone recommend any component changes to increase the volume?

4. I haven't hooked up the Presence control.  I have to mount it on the back.


Thanks for any advice.

BV

[dude]

My 6V6 plexi is very loud, no problem at a small club with any drummer but I have the PT from a Hammond AO43 340-0-340, B+ of 415v. I used a big 18 watt OT.  I don't have the PPIMV. I have Slucky's MV before the PI. Actually I have to lower the MV or it's too loud, even with a hard hitting drummer but I can't get the crunch of your clip without a pedal, very good cleans and loud.   


I was thinking of Putting a PPIMV in my 6V6 plexi and leaving the pre PI MV in too, putting the pot in the back. I do have a presence control W/22K feedback R on 8 ohm tap, works great. Has the most noticeable effect on the amp than any other Presence in an amp I ever played. The presence with each quarter turn gives my tone stack a whole different effect on the tone. With the upgraded PT and 6L6s, wow big tight low end and nice simmering highs.


If the PT you used can support 6L6, try that or maybe bypass the tube rectifier with diodes.


Note: maybe the dual pod on the MV is not the same on each side...? I hear people are using a $30 high quality pot for the PPIMV. 
 


al   

[brewdude]

At the risk of sounding like an ass, can’t you simply turn up the MV to be louder?

[purpletele]

My 6V6 plexi is very loud, no problem at a small club with any drummer but I have the PT from a Hammond AO43 340-0-340, B+ of 415v. I used a big 18 watt OT.  I don't have the PPIMV. I have Slucky's MV before the PI. Actually I have to lower the MV or it's too loud, even with a hard hitting drummer but I can't get the crunch of your clip without a pedal, very good cleans and loud.   


I was thinking of Putting a PPIMV in my 6V6 plexi and leaving the pre PI MV in too, putting the pot in the back. I do have a presence control W/22K feedback R on 8 ohm tap, works great. Has the most noticeable effect on the amp than any other Presence in an amp I ever played. The presence with each quarter turn gives my tone stack a whole different effect on the tone. With the upgraded PT and 6L6s, wow big tight low end and nice simmering highs.


If the PT you used can support 6L6, try that or maybe bypass the tube rectifier with diodes.


Note: maybe the dual pod on the MV is not the same on each side...? I hear people are using a $30 high quality pot for the PPIMV. 
 


al

Dude,


Thank for the reply.  This amp is typically very loud.  The previous configuration, which is what is in the video was super loud and the MV could only go up to 2:00 or it got too loud.


My intent was to make it a really manageable Plexi that sounded cool when you step on a boost or OD.

This Hoffman 6v6 Plexi has a SS rectifier installed.

[purpletele]

At the risk of sounding like an ass, can’t you simply turn up the MV to be louder?

Brewdude,

Under the current configuration, which is the standard Hoffman 6 v 6 Plexi with an added MV, the amp sounds great but everything is dimed.

Typically this amp is a bit wily and very loud, so I was surprised at the volume loss. 

I may have something wired incorrectly, or it may be I need to modify some components due to the MV, not sure.

I am sure that the MV is turned up.

Thanks,

BV

[Big_Mike]

I am probably going to build the Hoffman 6v6 Plexi, but insert a Rich Mod II PPIMV to the circuit with a PEC dual gang 500K pot.  Check out the George Metropoulis clip of his 50 watt with this type of PPIMV, it sounds really good.

I think all you have to do is to send each side after the phase inverter.caps to the right wiper of the pot and then the middle wipers to the output tubes.  The left side lugs of the pot would both go back to ground after the dual 100K resistors.

If I had the software, I would draw a diagram!

[purpletele]

I am probably going to build the Hoffman 6v6 Plexi, but insert a Rich Mod II PPIMV to the circuit with a PEC dual gang 500K pot.  Check out the George Metropoulis clip of his 50 watt with this type of PPIMV, it sounds really good.

I think all you have to do is to send each side after the phase inverter.caps to the right wiper of the pot and then the middle wipers to the output tubes.  The left side lugs of the pot would both go back to ground after the dual 100K resistors.

If I had the software, I would draw a diagram!

I'll check it out, I am curious about MV details.

I am playing the amp right now and the MV is working perfectly except It feels like the components of the MV are slightly oversized, like I need another 1/3 of volume. 

The previous configuration of the amp, which was the Mod 5, was hard to control the volume.  I couldn't get past 9:00 with the MV and it would blow down the doors.

I attached the detail from TopBrent that I used for the MV. 

It seems to me that I would want to reduce resistance through the MV to increase the signal. 

Not sure if I can decrease the 2.2 Meg resistors to 1 meg?, and if that is the best way to allow more signal through?

[Big_Mike]

Here is the page on the Valve storm site for the Rich Mod II PPIMV as installed on a 50 watt Plexi.  Scroll down to the bottom of the page for the wiring layout:

http://www.valvestorm.com/Amp%20Mods/PPIMV 

Here is the Rich Mod II PPIMV in action:

https://m.youtube.com/watch?v=vypgBhGQwJA

[purpletele]

Here is the page on the Valve storm site for the Rich Mod II PPIMV as installed on a 50 watt Plexi.  Scroll down to the bottom of the page for the wiring layout:

http://www.valvestorm.com/Amp%20Mods/PPIMV 

Here is the Rich Mod II PPIMV in action:

https://m.youtube.com/watch?v=vypgBhGQwJA

Nice video and instructions!

Thanks

[Big_Mike]

I used the Valvestorm wiring diagram to come up with the wiring I described above for the Rich Mod II PPIMV as adapted to the 6v6 circuit. The 6v6 has 100K resistors instead of 220K.  Not sure if that makes any difference for the PPIMV circuit.

[Big_Mike]

Also, the use of a PEC dual-ganged pot for the MV is supposed to be better at low volumes because of the consistency between both pots at any given level, much tighter tolerance than with an Alpha pot.

[purpletele]

Also, the use of a PEC dual-ganged pot for the MV is supposed to be better at low volumes because of the consistency between both pots at any given level, much tighter tolerance than with an Alpha pot.

I ordered a PEC pot to try on one of these.  The intent for me is to nail down the MV method that works the best and use it on a for a 50 Watt Plexi type thing.

It doesn't make sense to me why I lost volume with the Lar Mar, unless of course I wired something incorrectly.


I don't see a use for a dual conductor shielded cable, am I missing something?


BV

[purpletele]

I see what the might issue is on the loss of volume.

Lar Mar Question


Since the resistors that are being removed are 100K on the Hoffman 6 v 6 Plexi, should I be using a 100K Dual gang pot.  I do believe that makes sense.

If so, should I still utilize the 2.2 Meg resistors on the Pot?


BV

[MFowler]

The 2m2 resistors are safety resistors and should remain. 

Note from metro forum: rockstah wrote: Larry talk to me more about the 250k dual pot and the 2.2m resistors

The coupling caps are connected to the input lug's of the pot  - The bias supply voltage (which usually feeds the both 220K) is connected to the output lug's of the pot (of course to both)  - The pot's wipers are connected to the power tube's grids (or to their swamp resistors)  - Now simply solder each a 2.2M on each section of the pot from the wiper to the output lug - a small 1/4W resistor will do it 

These are only for safety, because if the pot's wiper fails, then the output tube's grid is w/o bias voltage and will immediately jump over  the Jordan. 

But with the resistor applied and a failing wiper, although this side can't be regulated anymore, but nevertheless there's bias voltage on  the output's grid - and the tube(s) will survive   Larry

100K/100K makes sense to use dual 100k pot.


I use Linear pots in my PPIMV recommended by an Ampgarage builder and also was listed in the first LAR-MAR layout I had seen years ago, then it switched to audio pot for some reason.


I don't understand why George M. is using 500k dual pot for PPIMV.


Mark

[Big_Mike]

For the Rich Mod II layout on a 50 watt plexi, George M. leaves the 220K resistors in place on the board.  Could you still use a 500K dual pot with the 100K resistors for the 6v6 plexi?  Or would that be unsafe?  I think I will try and see if I can get an answer to that from George M.

[sluckey]

I would choose the size of dual pots based on the size of the original grid resistors. Use 100K pots to replace 100K grid resistors, 250K pots to replace 220K grid resistors, or 500K pots to replace 470K grid resistors.

[purpletele]

Thanks guys!!

[Big_Mike]

I would choose the size of dual pots based on the size of the original grid resistors. Use 100K pots to replace 100K grid resistors, 250K pots to replace 220K grid resistors, or 500K pots to replace 470K grid resistors.

Sluckey, would there be any potential for damage in using a 500K or a 250K dual pot and keeping the grid resistors in place?  The Rich Mod II keeps the grid resistors in place.

See the link below, scroll down to the bottom for the wiring diagram for the Rich Mod II:

http://www.valvestorm.com/Amp%20Mods/PPIMV 

Mike

[sluckey]

No danger. I don't like the looks of mounting a terminal strip on the board. Looks much neater and less work to take the resistors off the board and put them directly on the pots.

[jojokeo]

No danger. I don't like the looks of mounting a terminal strip on the board. Looks much neater and less work to take the resistors off the board and put them directly on the pots.

Exactly, no reason for leaving extra components around. BUT, if left then these would be in parallel with the dual gang pot that it’s supposed to replace. The main reason to remove the original grid resistors.


Also gents - aside from sluckey’s earlier comment of using the same value dual gang pot that’s replacing those grid resistors (usually a safe bet), you always should refer to the datasheet of what power tubes you are using.


For 6V6’s it says maximum grid resistors are 100k for fixed bias and 500k for cathode bias.

[dude]

I was under the impression that installing La Mar PPIMV, one removes, replaces the power tube grids and replaces them with the correct dual pot. Taking out two 220ks, use a dual 250k, for 6v6s that use 100ks, use dual 100k. Is this not correct?   Talking fixed bias plexi.                                      Or can one keep the resistors along with the dual pot, some PPIMV have them, some don’t?  Can both ways work..? Just asking opinions.                                                                       al

[sluckey]

Works both ways

[dude]

Thanks, Sluckey. I’ll try both ways and compare them. al

[purpletele]

I changed out the dual gang to 100K dual.

It works much better but it still knocked the mojo out of the amp.

When I set it up for a clean tone I can have the MV dimed and (of course the master and two volumes have to stay low for a clean tone) and it is certainly not loud enough for a band.

I may just pull the MV and redo the face plate and use it as it was designed.

Great high gain stuff at low volumes though.

[Ed_Chambley]

Alright, time to teach Ed. Why would you use 100k on a 6v6gt when traditional designs like the AB763 Deluve  used 220k. Sure 12at7 but previous 6g3 used them as well.


Why would this value be selected for 6v6. Kt88, 6550 I get.

[sluckey]

This has been popping up a lot lately. RCA tube manuals (RC-19, RC-20, RC-30) clearly state that 100K is the max value for fixed bias amps and 500K is the max for cathode biased amps. These 'Maximum Circuit Values' values are found in the section labeled "Push-Pull Class A1 Amplifier". No wonder why all those Fender amps sound like shi┴ and blow up tubes every 30 or 40 years!   

[Ed_Chambley]

This has been popping up a lot lately. RCA tube manuals (RC-19, RC-20, RC-30) clearly state that 100K is the max value for fixed bias amps and 500K is the max for cathode biased amps. These 'Maximum Circuit Values' values are found in the section labeled "Push-Pull Class A1 Amplifier". No wonder why all those Fender amps sound like shit and blow up tubes every 30 or 40 years!   

To be fair, it is an old tube and I like running them low volts, cathode bias.  One of the new ones I am not sure what it is, but I know it has saved a lot of Super Reverb amps.  The JJ 6V6S runs just fine, however you do get a bit more power.


Truthfully, I have never considered using anything other than 220k, but I have not built a 6V6 Plexi, but I have a Plexi running 6V6 tubes currently, but I am putttinng the EL34 back.  Just a test really.


I believe it would be possiblle to boost into a non-master 6V6 with a plexi split cathode arrangement and achieve the plexi tone.  It is not like these amps were high gainers.  Actually, a humbucker will drive it some.

[dude]

My only dual pot that read both sides the same, very close, is a 1M, if I use a 1Meg R in parallel on the pots end tabs the pot reads like a 500k with both sides equal at all positons. Taking his in consideration can I use this dual changed pot for the PPIMV. I planned on using 220k grids with the changed MV pot, would there be any problem using this 1M pot?             al

[sluckey]

If I had to use a 1M pot I'd leave the 220K grid resistors in place.

[shooter]

I am putttinng the EL34 back

the El's, and channel mixing I believe IS most of the mojo in a plexi

I still can't figure out the why in PPiMV, a gain knob, a pre MVpot, the knob on the guitar, gives me big range of tone n volume at home, out, crank it to the venue, which is usually north of 7 on the amp and to flavor at the guitar 

[Ed_Chambley]

The idea of a 6v6 in a 1987 topology using 6v6 tubes will actually sound better or more marshall like as I really think the tube is basically a pentode. The 6k6 is a pentode and I wanted to see how hard I could run them.


I set a pair in a Tweed 5g9 with idle volts of just at 400 vdc using fixed bias and they ran fine at 70%, measured clean wattage, scope reads about 13. plus watts clean and 17 where the output wave is getting nice and flat.


To me, this output section sounds best cathode bias, even in a tight plexi circuit. The tone just at breakup between the 6k6 and 6v6 are to me identical,  I am not advocating 6k6 usage for a 6v6, but it can be Done. I simply have a stash, but they are cheap and easy to find.


I set the bias and it settled in at 92%, but the resistor is 330ohms. I actually use 5 watt wirewound not to quickly dial in bias. Then measure the pot. Since I never play at idle current, I put needle meters on to measure each tube. Matched at idle but not at normal output. One got colder. I tried a couple more and found a better conducting tube.


Seriously considering an inductor input plexi 6k6 build. O yea, it is just opinion, but I think copying the master from 2204 works best.

[jojokeo]

I changed out the dual gang to 100K dual.

It works much better but it still knocked the mojo out of the amp.

When I set it up for a clean tone I can have the MV dimed and (of course the master and two volumes have to stay low for a clean tone) and it is certainly not loud enough for a band.

Brian, did you install the treble bleeds on this? If not, I find that you really need them especially in the low to mid settings just like any other Vol pot using 1M for example. They all work the same and resistance is death to the high end. It's why all the negative comments on the LARMAR ppimv's, especially because people want that preamp disto - but you can't have your cake and eat it too kind of thing. There's always a give & take to most everything...

One other thing that people forget: when you're dialing down the MV it also affects (changes and reduces) any NFB and/or Presence control because there's less feedback going back into the pi.

[sluckey]

Seriously considering an inductor input plexi 6k6 build.

What is an inductor input?

[jojokeo]

The idea of a 6v6 in a 1987 topology using 6v6 tubes will actually sound better or more marshall like as I really think the tube is basically a pentode. The 6k6 is a pentode and I wanted to see how hard I could run them.

To me, this output section sounds best cathode bias, even in a tight plexi circuit. The tone just at breakup between the 6k6 and 6v6 are to me identical,  I am not advocating 6k6 usage for a 6v6, but it can be Done. I simply have a stash, but they are cheap and easy to find.

Seriously considering an inductor input plexi 6k6 build. O yea, it is just opinion, but I think copying the master from 2204 works best.

Ed, tubenit really likes 6k6s too but - have you ever tried using 6AQ5's (poor man's 6V6?) - these can be found even cheaper than 6K6s and both run at lower voltages comparatively to V6's... They sound damn good also! (I have a rather large stash of these also)

PS - where do you find all the time? Living in the woods?    (kidding  )

[jojokeo]

Seriously considering an inductor input plexi 6k6 build.

What is an inductor input?

I think he means choke input on the high tension filtration...

[dude]

If I had to use a 1M pot I'd leave the 220K grid resistors in place.

Sorry, now I'm confused. I use 6L6's in my 6V6 plexi at times for more beef, I have 100K grids on the power tubes (plenty of volume W/6V6s amp is very clean and loud, same schematic as you and Doug, MV before the PI but was going to change to 220k grids (from 100k) leaving these grids in and also adding a PPIMV on the back panel. The good reading dual 1 Meg, I planned on changing it to 500k (1 Meg across the outer legs). The reason for the added PPIMV with the pre-MV was I had to have the amp rattling the windows to get the power tubes to distort, plenty of preamp distortion.
Figure with both MV volumes, I'd get the best of both worlds. You mentioned "you'd use the 1 Meg Dual pot with 220K grids", maybe you were saying use the "changed" 1 Meg (now 500k changed) w/220 grids?


This amp is the loudest 6V6 amp I ever played, very loud clean tones. I did use the Marshall Bluesbreaker caps on the Bright volume, only change.


Any problem using both MV's?


al


 

[sluckey]

You mentioned "you'd use the 1 Meg Dual pot with 220K grids", maybe you were saying use the "changed" 1 Meg (now 500k changed) w/220 grids?

You twisted that just a bit... Here's what I really said...

If I had to use a 1M pot I'd leave the 220K grid resistors in place.

I was responding to your post about using a 1M mv pot. There was a big emphasis on the word "If", even though you can't see it.  But I don't have to use a 1M pot, so I would use a 250K pot with 2.2M resistors mounted on the pot and I would remove the 100K grid resistors from the board.

However, IF I had to use a 1M pot I'd leave the 220K (or 100K) grid resistors on the board. No resistors on the pot because you already have resistors on the board. 1M parallel with 220K gives 180K. 1M parallel with a 100K gives 91K. Either is fine for a 6V6 grid so you're covered if you have either 100K board resistors or 220K board resistors.

My point... You don't need a dual pot and four fixed resistors. Simplify and use a dual 1MA pot with the resistors on the board. No pot resistors. It'll look neater.

As far as using two MV, do it. Your playing ability will climb a step higher. All the other guitar boys will be jealous!   

[dude]

OK, I got it. When they use the 2.2Megs, wiper to ground, they're there to prevent a bias problem if the wiper pot goes south and no grids on the bd. (BTW, always wondered where that idiomatic expression "going South" came from, maybe you know). 


Anyway, with the 220k's or 100K's on the Bd, no need for the 2.2Ms as I have the bd grids to protect if the pot goes "South" and  like you said in parallel grids are fine for 6L6s or 6V6s (there I go again with the South thing...).


Can't wait for my playing to go through the roof,    .  Just came back from the Philly Guitar Show, sure going down the hill from years ago. They did have two AO-43's there for $150 each, prices are crazy high, better deals on Craigslist, Doug's Parts are cheaper too.


Thanks Steve

[Ed_Chambley]

Seriously considering an inductor input plexi 6k6 build.

What is an inductor input?

You know.  An inductor, or sometiimes refereed to as a Choke, Coil or reactor.  They are passive components generally consisting of an insulated wire around a core.  Need to know what a core is?  The reason I would think it is called a Inductor is because of Michael Faraday Law of Induction.  When the component blocks (or chokes) DC and allow AC, this is operational characteristics of a inductor. Inductors are used extensively in analog circuits and signal processing. Applications range from the use of large inductors in power supplies, which in conjunction with filter capacitors remove ripple which is a multiple of the mains frequency (or the switching frequency for switched-mode power supplies) from the direct current output, to the small inductance of the ferrite bead or torus installed around a cable to prevent radio frequency interference from being transmitted down the wire. Inductors are used as the energy storage device in many switched-mode power supplies to produce DC current. The inductor supplies energy to the circuit to keep current flowing during the "off" switching periods and enables topographies where the output voltage is higher than the input voltage


You can call it a choke if you want, still will not help crank your lawnmower when it is cold.

[purpletele]

I changed out the dual gang to 100K dual.

It works much better but it still knocked the mojo out of the amp.

When I set it up for a clean tone I can have the MV dimed and (of course the master and two volumes have to stay low for a clean tone) and it is certainly not loud enough for a band.

Brian, did you install the treble bleeds on this? If not, I find that you really need them especially in the low to mid settings just like any other Vol pot using 1M for example. They all work the same and resistance is death to the high end. It's why all the negative comments on the LARMAR ppimv's, especially because people want that preamp disto - but you can't have your cake and eat it too kind of thing. There's always a give & take to most everything...

One other thing that people forget: when you're dialing down the MV it also affects (changes and reduces) any NFB and/or Presence control because there's less feedback going back into the pi.

I did install the treble bleeds on this one.

The MV works well as mentioned but is fairly well subdued.  I'll probably disconnect it and see if the amp is performing as designed, I think it is.

[Ed_Chambley]

The idea of a 6v6 in a 1987 topology using 6v6 tubes will actually sound better or more marshall like as I really think the tube is basically a pentode. The 6k6 is a pentode and I wanted to see how hard I could run them.

To me, this output section sounds best cathode bias, even in a tight plexi circuit. The tone just at breakup between the 6k6 and 6v6 are to me identical,  I am not advocating 6k6 usage for a 6v6, but it can be Done. I simply have a stash, but they are cheap and easy to find.

Seriously considering an inductor input plexi 6k6 build. O yea, it is just opinion, but I think copying the master from 2204 works best.

Ed, tubenit really likes 6k6s too but - have you ever tried using 6AQ5's (poor man's 6V6?) - these can be found even cheaper than 6K6s and both run at lower voltages comparatively to V6's... They sound damn good also! (I have a rather large stash of these also)

PS - where do you find all the time? Living in the woods?    (kidding  )

First, to live in the woods you must be resourceful.  Another thing is I get no distractions so I can actually read a textbook without getting texts, emails, phone calls and generally disrupting my concentration and therefore my retintion increases.


I have a Fender amp that came with 2 6AQ5.  It is/was a little bass amp.  Forget the name, but you have seen one. YOu can still get them fairly cheap.

[shooter]

to live in the woods you must be resourceful.

YeSSSS, I always love having the city folk get lost, wind up in my backwoods gas-stop, deer in the headlights look, GPS not working, and I just get a piece of paper and sketch out "how to get there", ....see the big green machine with a 20' pile of wood in front, turn right there 

[jojokeo]

Shooter that’s how my wife and her friends give directions to each other, barely even mentioning street names. And we do live in the city with all sizes of streets everywhere. They don’t even know the difference between north south east or west.

[shooter]

don’t even know the difference between north south east or west.

I "gauge" society by things like this, also things like small cart, large cart, returns at grocery, txting while driving,..., my conclusion, the human race as a whole is doomed 

[dude]

I put the Rich PPIMV Mod II in my 6V6 Plexi, used a 1M and 270K bias grid R, gives me 210K with PPIMV pegged. Also, left the Pre-PI MV in too. The two go nicely blended together. Of course, if you turn down the PPIMV, you lose presence but only if more than a third or more backed off but you have the pre-MV to lower the overall volume to compensate so you don't back it off too much. Not looking for bedroom levels but gigging levels. Doing these two MV's you really don't need to add a top cut either if you don't turn the PPIMV down more then a third. 


I now find the amp is much more useful, with the normal and bright to blend as usual, you now have the Pre-and Post Master to blend, you're able to keep the PPIMV high enough to keep most of the presence too. I tried 6L6s and the amp really is beefy, think Led Zep, EL34s really shine but then your back to a real JTM-45 Plexi. Nice to have all these options, though.


Only problem with the 1Meg PPIMV is the first 1/3 turn does all the lowering, (the slightest turn affects the volume) might go to a 500KA dual and whatever R  to get about 220K on the grid bias resistors with PPIMV wide open.  All in all, my opinion both MV's work well together in the Plexi 6V6.


al     

[jojokeo]

Yes but try 100pF across both sides of dual pot PPIMV and you’re golden.

[dude]

Yes but try 100pF across both sides of dual pot PPIMV and you’re golden.

                Just did it, nice. Even better than I expected, now I just need to get a better spread on the PPIMV. Don’t know if a lin. or audio pot is best. Maybe just get a dual 250k, take the bias grids off the bd., add two 2.2Ms to pot...?  Of course use the bright caps, what would give me a more even response on the pot? Lin, aud, 500k, 250k. But i’m stoked, the bright cap is a must on the MV dual pot, thanks.    al