New(used) Pro Mod owner and Questions

[DonaldDemon]

I got my Pro Mod yesterday from kurtsstuff (3rd owner in 3 months ). I haven't really put ot throughthe paces yet but I will tonight at practice. It seems like it really needs to be cranked to come alive and get the gain kicking.
I was going to try some different preamp tubes I had lying around but I wanted to know which tube does what. Is there a phase inverter tube that I need to be balanced? Are they all just gain stages? This might be a question for Scott but I hate bothering busy people. Any help is appreciated.

[Hacksaw]

To start... Usually V1 ( tube one) is closet to the guitar input, this tube has the effect on the clean channel and dirty channels. If you like your clean sound, leave V1 alone. as it is the only tube that is ran into the clean channel circuit. If you want a dirty channel tone change, I would change V3 as a start.

Preamp Tubes v2, and v3 are ran with v1 for the dirty channel.

The Phase tube is a balanced tube. and usually offset from the others. This is the only balanced preamp tube in the amp that should be balanced. The other preamp tubes dont use balanced. in most amps. ( again I havent ran across a amp yet that uses balanced tubes in V1,2,3. )

all preamp tubes have the ability to be balanced, its the testing of the tube checked for equal current draw on both sides of the preamp tube.

This probably wont change the fact you have to crank up a bit to get the tone, I usually ( on my bogner etc..) have to crank up to almost 2 on the mains to get the amp alive.

I know of a few people around town that use bigger amps, use the THD hotplate to help with this. gets the amp throttled up, then back down the Hotplate.

splawnfans.proboards38.com/index.cgi?board=mostpeoplehavemorethanoneampguitardiscussthemhere&action=display&thread=1124063837

anyone? Did I miss anything or??

hyperlink splitting ?? dunno why

[craggin]

Hacksaw, that is good info...I presume the same layout applies to the QR, too?

[Hacksaw]

Hey Craggin, Yes...also the same Tube layout for just about all amps. Bogners, QR, Marshalls, and all the rest are all about the same tube structure. Even Crate Blue Voodoooo's... I have been tweeking on amps for about 2 yrs now. all have the same tube layouts! I played around on a mig amp to learn about amps.. you can get one pretty cheap, then I tried a few things on my bogner, and my marshalls.. its very interesting what changes a tube will make :-) I ended up with chinese tubes in V1&2, and a JJ ECC83 on V3 on the bogner. I tested on a crate Blue Voodoo ( another test amp to learn on) and tried this, I didnt like that combo.. ended up with all chinese.. love trying tubes. the JTM45 is fun to change tubes on.. it likes a lot of combinations.

[craggin]

That's cool, hacksaw. I've got a BUNCH of preamp tubes laying around...I think I'm going to set some time aside this weekend and experiment with the QR to see which combo of tubes sounds best to my ears. I've already played around a little bit and found that so far, I like the JJECC83s the best in V1 but I haven't tried any of my NOS tubes in there. (But I will...)

[Hacksaw]

Cool , let me know what you end up trying! I also was told years ago by a amp veteran, to keep fingerprints off the tube. as that will cause hot spots. I dont know if this is really true, or a hyperthetical thought. I do change tubes using a soft cloth.

[DonaldDemon]

hacksaw said:

The Phase tube is a balanced tube. and usually offset from the others. This is the only balanced preamp tube in the amp that should be balanced. The other preamp tubes dont use balanced. in most amps. ( again I havent ran across a amp yet that uses balanced tubes in V1,2,3. )

all preamp tubes have the ability to be balanced, its the testing of the tube checked for equal current draw on both sides of the preamp tube.

.

splawnfans.proboards38.com/index.cgi?board=mostpeoplehavemorethanoneampguitardiscussthemhere&action=display&thread=1124063837

anyone? Did I miss anything or??

hyperlink splitting ?? dunno why

Thanks for the info. I tried some different tubes and the original JJ's sound the best. So does this mean there is no phse inverter tube? That's basically what I got since there is no offset tube and V1-V3 are gain tubes.

As for the volume issue I will have to see how this thing does live. I have heard the power brakes kill the tone and make it brittle so I am hesitant to use them. Thanks

[Hacksaw]

I will have to look at the circuit in my quickrod ... when i get it!! any day.. to see how they did the Phase inverter tube.. or what they did to eliminate it.. they may have used the phase on v3, that would be like the old jtm45 etc.. I thik pre 1990. I know dirrty craig has posted pics of his amp interior, but I cannot seem to find where it is.. but I bet v3 is the inverter if there isnt a tube offset somewhere.

I have also heard mention from the guys on this forum, they yse the midiverb 4 to control the volume and crank up the amp, maybe that would help with your issues ?? I havent tried that with any amp.. I just crank em up.. but I am out in the country. My friend uses a THD and sounds pretty decent..

can anyone reffer?

[craggin]

Donalddemon, as far as I know, every tube amp has a PI, it is usually the preamp tube furthest from the input jack or in my QuickRod (I assume the same for the ProMod) "V3".

I played around with some preamp tubes tonight, I had some NOS Siemens, NOS Mullard, NOS Ge, EH12AX7, Chinese 9th gen 12ax7, JJecc83s, JJecc803, JJecc81, Ruby 7025ss, GT7025, and a NOS GE12at7.

I've gotta say, it was hard to beat the JJ's that came stock with the amp but the Siemens sounded best in the V1 slot. The Mullard that I have is pretty worn, so it wasn't a good representation of what one would sound like. Everything else sounded a bit too harsh compared to the JJ's...even the Siemens was a bit more harsh but it made up for it with harmonic content. The Siemens had a bit more "bite" and slightly better harmonics, but it wasn't by as much as you'd think.

I played roulette with the tubes in V2 and V3, but settled on the JJecc83s in V2 and the JJecc81 in V3. (I noticed no difference between the GE12at7 and the JJecc81, so I kept the GE as a backup.)

As I said, it was tough beating the stock JJ's, Scott Splawn really tailored the amp nicely around them. Is it worth putting NOS tubes in the Splawn? Probably not unless you have some laying around, the marginal increase in tone (and I stress marginal) probably isn't worth the extra money. YMMV.

[Hacksaw]

There is a few designs that moved the Phase Inverter around the chassis in marshall amps.. a good primer for this can be found here, it may help to reconize different structures in the models of amps. I cant wait to see the inside of a QR, or a PM, as it will let me know what it is based off of.

marshall.redpt.com/clay/marshall_circuits_101.html

[shreder75]

I have a midiverb 4 for sale!! =D

[Hacksaw]

Whats the price on The Midiver4?

[shreder75]

$100 ...manuals, chords, good condition..just some rack scratches on the mount..but you can't avoid that....buy it..I'll be your best friend! lol....I need the cash so I can't afford to keep it

[DonaldDemon]

shreder75 said:

I have a midiverb 4 for sale!! =D

There ya go hijacking my thread with your darn Midiverb again. Will someone please buy this thing! ;D J/K man.

I don't have any rack equipment and I don't want any. I need to set up in 15 minutes time most shows and it would just be impractical.

I thank you guys for your thoughts. I assumed the PI tube was the V3 as well because I think every tube amp has to have one. When I ordered tubes they had marked the boxes with which ones were balanced but I managed to mix up the boxes so I am not sure now.

The JJ's are probably the best choice for any Marshall or Marshall clone amp becasue they just seem to fit that voicing best, My last amp was so picky about preamp tubes so I thought I would give it a try. I reaaly thought the GT Mullard reissues would sound better but they were too dark sounding.

I am still not sure about this amp though. It is like an old Marshall with more gain but not quite enough. I would hate to have to use stomp boxes to get into real saturated territory. The efx loop also bothers me because it affects the tone in a bad way. This is unacceptable for me because I run my delays and pitch shifter thru the loop. I record with it tonight and I hope it will get there for me on the recording.

[shreder75]

well someone mentioned the alesis so I thought i'd throw it in there

by the by, don't be afraid to dime the gain..it won't fart out on you...

what about on OD2?? you don't think it's got enough gain on OD2?

see, told ya you shoulda gotten a QR w/ third gear..lol...just bustin chops