Master Volume in a Fender 5e3 Deluxe??

[dovii]

Hey, has anyone put a master volume in a 5e3? My wife loves the sound but hates the volume if you know what I mean. I found a mod in the 18w forum for Marshalls, just wondering if I could apply the same mod to a fender.

Thanks

[dave g]

Dunno how well it would work...most of the distortion in a 5E3 comes from the output stage.

Why don't you try Dana's VVR circuit?

[Greg Smith]

I built a PPIMV into my Marshall 18 power amp, and I would say that it was one of the biggest breakthroughs I've made in amp tinkering. True, a lot of the overdrive in the Marshall 18 and the Deluxe does come from the output tubes, but the addition of an MV allowed me to increase the clean range of the volume control. In the case of the stock Marshall 18, the clean range is from about 0 to 2, after which you are into overdrive and high volume. The MV made the amp a lot more "livingroom friendly".

Also, the MV allows you to balance the amount if overdrive generated in the preamp/PI, versus the output tubes. This becomes particularly useful if you should be driving the amp with a boost pedal, or choose to add an additional gain stage to the preamp (as I have done).

Note that, in the case of cathode-biased output stages, you don't need to add a second pair of coupling caps between the MV and the output tube grids. Just connect the existing coupling caps to the tops of the MV pot gangs, and connect the wipers to the tube grids (bottoms of the gangs to ground). I would leave the existing output tube grid resistors in place. I used a dual 500K linear pot that I had laying around and it worked well.

In short, this mod would be well worth trying, IMHO.

Greg Smith

[Cygnus X1]

There are many discussions of this concept at this other place...
one thread for example:

http://music-electronics-forum.com/show ... ter+volume

Not pushing their site, just some interesting views on the topic.

[jjman]

In this particular case I would go for an attenuator. Easy, quick, preserves OP tube distortion.

I used a PPIMV on my 5e3 output amp, but it has an Express input/PI so plenty of PI and Pre distortion available.

Has anyone documented or observed which stages break up in a 5e3, and in which order?

[Alexo]

I've always had the impression that the 5E3 overdrive comes from about 60% pi distortion, 20% output tube distortion and maybe 20% pi-driver distortion. Never scoped it out or anything, this is just my gut feeling on the matter, so take it for what that's worth (nothing?). IF that's true though, a post-pi mv would be fairly effective.

[dovii]

Ok, thanks for the replys. Went to other sites and did some reading. Here is what I came up with. I will try this on the weekend and I will get back either way. Any feedback is greatly appreciated.

[tubetek]

Have you looked into one of the VVR (Variable Voltage Regulation ideas being kicked around the web lately? I'm using one like I've posted below; simple and very effective. Hope this helps...
Tom

[bcmatt]

Seriously! Do that basic VVR Circuit. Don't mess with the balance of the amp. I installed that basic VVR in my friend's 5e3 and he absolutely loved it. It's like it was made to have VVR. It worked amazingly well for that amp; scaling the whole amp. There wasn't even any pot scratchiness problems.
It is the most perfect candidate for the basic cathode biased VVR.
It's how you would dream the most true and perfect Master Volume would work. It just makes the amp quieter.

Ever since we added the VVR to that amp, it has become one my most highly recommended amps for someone that is looking at their first tube amp, but they don't want anything too complicated; but still versatile, great sounding and portable. I wouldn't recommend anyone having a tweed deluxe without VVR. VVR may not be the best recommendation for every single amp in the world, but it is a must have for every 5e3. That's my two cents.

[dovii]

Ok, Ok, I will try the vvr. Didn't realise guys you would be so passionit about someone messing with a 5e3:) I will get back with my conclusions in a couple of days. Wunderbar

Did you hear about the dyxlexic who walked into a bra?

[Deric]

I did the PCB layout posted above - it works fine, but - I recently found another way to sneak it into a tight space with very little extra wire. I used a 1M Linear pot with a built in SPST switch in place of the stock Power switch. The PCB mounts directly to the pot and the Mosfet. Click "On" then adjust power as needed.

Here's pics in a Trinity TC-15:

[IMG:160:120]http://i40.photobucket.com/albums/e243/stumper1/TC15/th_TC15026.jpg[/img]
[IMG:160:120]http://i40.photobucket.com/albums/e243/stumper1/TC15/th_TC15024.jpg[/img]
[IMG:160:120]http://i40.photobucket.com/albums/e243/stumper1/TC15/th_TC15023.jpg[/img]


Here's the PCB transfer and parts layout:

[IMG:112:159]http://i40.photobucket.com/albums/e243/stumper1/TC15/th_VVRooM13.gif[/img]
[IMG:160:150]http://i40.photobucket.com/albums/e243/stumper1/TC15/th_VVRooM13PnP.gif[/img]

All credit goes to Dana (UR12) !!!!

[rutledj]

Do you have to use an insulator between the mosfet and case?

Also I don't see a 6v 1w zener at mouser. I see a 5w version. Is that too big?

Rut

[Deric]

Do you have to use an insulator between the mosfet and case?

Yes. The NTE parts come with one.

Also I don't see a 6v 1w zener at mouser. I see a 5w version. Is that too big?

FWIW, Dana (UR12) has switched to a 12v zener.

I believe I used this: http://www.mouser.com/Search/ProductDet ... dLFw%3d%3d

[rutledj]

Thanks. Just placed an order for these parts.

Question. On a 40-50w amp, how quiet can you get with this implementation?

Rut

[tubetek]

Question. On a 40-50w amp, how quiet can you get with this implementation?Rut

What amp are you planning on VVRing? This circuit is for cathode-bias ampd only. If you have a fixed-bias amp, additional circuitry is needed to track the bias with the B+. Hope this helps...
Tom