Me and my Hot-Rodded Pignose G40V!

[PraiseCaster]

I just had my Pignose G40V modded, and I gotta tell ya, it is now seriuosly one of the best, if not the best amps I have ever had, combo or not!

I've had Twins, Marshall's, Champs, and assorted ss amps not worth mentioning, and this little amp kicks major hiney!

Dennis Kager of Ampeg fame designed the G40V. The circuit of the G40V is based on the 59 Fender Bassman, which was also the basis of the original Marshall amps. Gary at Mould Music said he came up with a mod to get it right into Bassman/Plexi land.

Boy was he right!

The big drawback with the G40V is there is very little sway in the Presence Circuit. Gary came up with a mod that brings that circuit too life. Its huge the throw that the presence knob now has, and it brings out a lot in the amp I never knew was there.

This amp goes from clean to crunch, and articulation all across the spectrum! The bell-harmonics ringing out of those tubes sound like its coming right out of a cathedral!

Overdrive! Wow! Creamy, smooth and blistering! This thing will sustain for days! The tone just knocks me on my butt it is sooooo sweet! And that is just through the stock 10 inch speaker, that now sounds totally awesome all across the board (it used to sound flubbery when pushed hard: not any more)! Push it through a 4-12, and its, "OH MY GOD!! That is too cool!!!!!! Unbelievable, totally unbelievable. It doesnt have nu-metal overdrive, but it gets you into classic metal, and hard rock with authority!

I've played a lot of amps, and even though I liked my little piggy, I often thought, "I would like to get one of those new Bassman RI's." I dont think I will be wantin that bassman anytime soon. This little combo amp, is what I would call a giant killer now!

Who woulda known that a little 200 dollar, no frills tube amp, packed such a major punch too it!

[3StringGuitar]

Back before I got my Sovtek tube head I had looked into thoes Pignose amps. Actually I bought their head unit, the G60VH I think it's called, unfortunatly I never got it and got a refund insted due to them being out of stock, I think more like out of production. I've heard so many good and bad reviews of these amps though, never any in between. I'm glad you're rockin' yours though. Any sound samples? I'd love to hear one again to compare it with my amp, I think I can get pretty close to the Pignose Marshall sound actually. How's the reliability on it you think?

[captain gorgeous]

Dennis Kager of Ampeg fame designed the G40V. The circuit of the G40V is based on the 59 Fender Bassman, which was also the basis of the original Marshall amps

one of the loveliest amps i've ever played through was one of those early JTM45s. lovely shimmery harmonic laden cleans that wound up into the most satisfying crunch with loads of rectifier sag. it's a sound that i've had in my head for a while now. replicating it on a budget is something of a quest of mine...

can tell me more about these pignose amps?

[captain gorgeous]

Who woulda known that a little 200 dollar, no frills tube amp, packed such a major punch too it!

list price is $549.99 (but $319 on the pignose site)

[PraiseCaster]

I have had zero reliability issues with my G40V.

Now, looking into the chassis, it aint pretty: I have seen a lot better looking innards than the Pignose, but nothing I would say is poor quality.

I got my amp a little over 3 years ago. I think Pignose listed it on their site for about 329 bucks. I saw it at most places for about 229 to 250 bucks, but this one had a little blemish on the bottom right (nothin bad, just a blemish), and I joked with the guy at the little shop, "Hey how bout 200 bucks out the door, because of this gross disfigurement here?". He looked at it, and said, "Sure, I got no problem with that." I musta had the stoopidist look on my face, as it took a moment for it to register that I just got a brand spankin new tube amp, out the door, for 200 dollars. I think I just about knocked over a display as I reached for my cash!

I still see them in that same little shop for around 250 bucks.

The Pignose G40V and the 60, are very similar to a Reverend 60 watt amp (cant recall the moniker), that Dennis Kager helped Ron Naylor on.

This amp has a Volume, Master Volume, Bass, Treble, Middle, and Presence controls. No Reverb. 10" "Pignose" speaker with a huge ceramic magnet.

The stock Chinese tubes are grim, but if you throw some good tubes in there, its like you got yourself a whole new amp!

Its just simply amazing that this little combo packs such a huge wallop too it! For me, it has been totally, Best Bang for My Buck!

Now, support from Pignose? Fergedaboutit! But at such a low cost, its a great platform to build upon, and it wont bug you to void the warranty since you didnt shell out a lot of cash. But like I said, I have had zero reliability problems.

[bluescube]

More details on the mod please?

I should have bought one from MF back when they were $220, now they are $100 higher.

At $399 I'll get a Carvin Vintage16 or an Epiphone Valve.

[PraiseCaster]

I'll ask the guy who came up with the mods if I can post all the details (he even has a schematic showing all the mods).

I have heard a lot about that Epiphone Valve Junior combo and head: Lotsa people raving about bein the best dang 5 watt, one knob amp, packed with lotsa tone! Someone said MF is bangin em out for 99 bucks (both the combo and the head). Something though about the combo has to be a certain serial number, because they made a huge change that improved it greatly. I'm tempted to sell my little Alamo Capri amp to get one of those Epi Valve Jr. heads.

I would like to put my Pignose up side by side with a Carvin Vintage16, though my amp guy (who does a ton of Carvin work, seein he is a former Carvin employed amp-guru), said the Vintage aint the best stock, but there's some great tone to be unleashed there with a few mods.

[big jimmy]

I have a blues brothers dvd tat has some of their songs on it. Best of the blues brothers. Steves tone has always been 1 of my favorites. He is playing a fender amp but I have no idea which 1. It looks to have a single speaker in it. Anybody know which model it is he plays? Going to try and make to memphis in the mud this weekend to catch booker t and the mg's. Maybe I can get close enough to see for my self. Hope he plays his tele and not that cort thing.

[big jimmy]

that was supposed to be a new post. But i do own a gv40. Put new tubes and a red coat speaker in it for a great improvement. Would like to see the mods.

[PraiseCaster]

You can see all the mods, and there is a link for the schematic diagrams here:

http://www.guitaristpraiseforum.com/...+g40v&start=20

I did not do the mods myself: My soldering work is lowsy, so I left it to the pro's!

I'm still dumbfounded as to how great this amp sounds now!

[PraiseCaster]

Here's all the mods, and a warning:

DISCLAIMER:

The following modifications will void your warranty. Do the modifications at your own risk. If you do not know how to safely work with high voltage circuits, STOP. Refer modifications to qualified service persons. High voltage can kill you. DEATH IS PERMANENT. The author and this site accept no liability for anything you do or for damages resulting directly or indirectly from the following modifications regardless of whether or not the modifications are performed according to this article. Proceed at your own risk.

Unplug the amp from the power source. Wait a minute for the high voltage power supply capacitors to drain. Access the amp chassis by first removing the speaker baffle assembly. Remove the louvered metal tube shield on the back. Remove the output tubes and set them in a safe place. Unbolt the chassis and remove it through the front of the cabinet.

NOTES: The changes to the original circuit are marked in red on the modified schematic.

The original schematic shows a 1.5 amp fast blow fuse. The chassis on my 2003 model is marked �2A Fast Blow� and does indeed have a 2A fuse.

When installing replacement resistors, use resistors of � watt rating or greater. Do not use � watt resistors in high voltage circuits.

The output tube bias circuit is adequate. I did not attempt to modify it as a variety of 6L6GC and 5881 tubes were within normal dissipation ratings when simply installed into the amp. YMMV.

ELIMINATING HUM

The biggest issue with a G40V amp is the hum which is caused by poor ground wiring. To eliminate it, modifications will need to be performed in two areas. Familiarize yourself with the modified schematic. The goal will be to ground the preamp circuitry to the chassis at the input jack and the output stage circuitry to the chassis at the output jack.

1. Replace the input jack with a metal shorting Switchcraft unit. Remove the 1M resistor from the old jack and attach it across the new jack. Attach the shielded input cable ground, tone control board ground and the black ground wire from the old jack together on the ground lug of the new jack.

2. Remove the knobs and potentiometer mounting hardware and carefully work the potentiometer PCB past the power supply filters to gain access to the foil side of the board. Refer to the filament/LED circuitry on the schematic. We want to cut the ground plane for the two, 100 ohm, 1-watt resistors between the resistor/LED circuit and the tone control ground. This will leave the tone circuit grounded at the input jack via the black wire on the other end of the PCB. Tack-solder a 22ga wire on the PCB at the junction of the two 100 ohm resistors. Connect the other end of the wire to the chassis ground at the green wire from the power cord adjacent to the power supply board. This moves the resistor/LED circuit ground point to the chassis. Filament circuit grounding is no longer through the tone control circuit ground.

59 Bassman/Marshall Type Tone Modifications

The circuit of the G40V is based on the 59 Fender Bassman, which was also the basis of the original Marshall amps. Though lacking a tube rectifier, we can voice the amp to sound more like it�s predecessors.

1. Lift the signal lead from the input jack at V1 pin2. Solder one end of a 33K ohm resistor to V1 pin 2. Slip a piece of shrink tubing over the signal lead. Attach the signal lead to the other end of the resistor. (Keep the resistor leads short.) Shrink the tubing over the resistor to insulate the connections.

2. Lift the wire from V2A grid, at the tube socket. Insert a 68K ohm resistor in series with the grid, as in item 1 above. This simulates the Miller Effect high frequency roll off in the Bassman channel mixer circuit, which the G40V lacks.

3. Change C12 from a .001mfd to a 220pf silver mica.

4. Change R19 from a 33K ohm resistor to a 56K ohm resistor.

5. Remove C13.

6. Change R26 from a 100K-ohm resistor to a 27K ohm resistor.

7. Install a 47pf, 600V capacitor between the plates of the PI driver, V3.

Presence Control

Here�s where things get a little tricky. Read this through a couple of times and check the schematic before proceeding. The presence control circuit of my 2003 G40V does not match the popular schematic. The modifications schematic has what my amp contains drawn in a box and noted. We want to modify the circuit to the Bassman style.

Remove the 4K7 resistor from the tone control PCB. Remove the .1/400V Presence cap and save it for later. Carefully cut the trace running between the presence pot center wiper and the low side of the pot. Install an insulated jumper wire between the ground side of the 4K7 resistor you removed to the high side of the where the .1/400V cap was. The low side of the presence potentiometer should now be grounded. Install a new .1/100V green poly cap from Radio Shack between the pot center wiper and ground. Remount the tone control PCB.

More Bottom

Take the .1/400V cap you just removed from the presence control circuit and replace the .022uf cap at C17 with it.

Reassemble the amp and install the tubes.

After the above modifications I can dime both the volume and master controls and the hum level is lower than the hiss of the amplifier. With a Stratocaster, the amp gets great Hendrix tones and cleans up as the guitar volume is rolled back. The amp sounds louder and has much more low end, even with the stock ten inch speaker.

One could go further toward 59 Bassman voicing by the following:

1. Change R25 to 82K ohms.
2. Remove C21 and C9.
3. Move the R26 feedback connection from the 8 ohm output tap to the four ohm tap.
4. Change C19 and C20 to .1mfd, appropriate voltage rating.
5. Remove R3 and install a choke.

Here's the schematic diagram with all the mods in red:
http://img.photobucket.com/albums/v6...mods120505.gif

I've had all the mods performed on my amp, plus I have some great NOS tubes installed, though I heard one with all the mods and only the stock chinese tubes, and it sounds almost as good!

I'm tossin around the thought of trying a different speaker, but with all the mods now, this speaker sounds really sweet! For kicks I still might try out a Celestion Greenback, and an Eminence Patriot "Delta Demon", just too see what they sound like. At this point I am not going for any drastic changes to my amps performance or tone, but just maybe tweak it a bit, and see how she sounds......

[azure0099]

What were the wattage values? They don't show up in the post.

[PraiseCaster]

The wattage values? I'm not really sure. I'll talk to my old amp guy and see what he tells me.