Express with Variable Voltage Regulator

[UR12]

Steve

I have posted the schematic for the cathode biased version of the circuit. I don't have any plans to posted the fixed bias version at this time. You can contact me via email or PM and I can hook you up with either a blank board that you supply all the parts or a preassembled cathode bias board for use in the liverpool or a preassembled fixed bias board for use in an Express.

I don't use an extra transformer to implement the bias tracking. The boards come with instructions

[sst4270]

Dana,

Thanks for the response. PM sent.

Steve

[billyz]

Dana,
Did you apply the VVR to the whole amp or just the power tubes? What brand of can caps did you use? Looks too clean.

[UR12]

Dana,
Did you apply the VVR to the whole amp or just the power tubes? What brand of can caps did you use? Looks too clean.

I did the whole amp. My thinking is to keep it with one knob and by lowering all of the voltages across the board I can keep the gain structure of the amp intact which I think is important in the TW style amps. The cap cans are JJs, dual 50 @500 and a 40/20/20/20 @500.

[billyz]

I love the clean layout of your build.

[Krinkle]

Is this method still working well for everybody? Any boards left? How much do they cost (I would supply parts).

Thanks,

Darrin

[UR12]

Hey Darrin. I do have a few boards left. Just PM me for prices. All of the Expresses I have built were built for other people. I haven't had any contact with any of the owners for some time now so I would guess that no news is good news. I personally have amps here with it installed, my Liverpool and a couple of others that get used on a weekly basis for the last couple of years and have not had one failure as of yet.

Once the VVR2 boards are gone, I will be ordering a newly designed couple of boards. By popular demand , I have redesigned the VVR into a smaller footprint for the fixed bias (so it will fit on the side of a Fender chassis better) and will have a new smaller version cathode bias board. These should be in in about 4 weeks. I will probably stop selling the blank boards and only have about 12 left. I am also looking at coming out with a complete power supply board with a fixed or cathode bias and HV section along with the VVR that can be used in any new amp design.

[kineteks]

Dana, so I didn't need to do this? A smaller footprint VVR, just what the doctor ordered! This is all that's required for an Express, no? Will you be doing TW specific boards?
FWIW this will fit under the power supply board if one wanted a "stealth" installation. These are going in my TW trio....
VVR+TW rules!

John

[UR12]

Dana, so I didn't need to do this? A smaller footprint VVR, just what the doctor ordered! This is all that's required for an Express, no? Will you be doing TW specific boards?
FWIW this will fit under the power supply board if one wanted a "stealth" installation. These are going in my TW trio....
VVR+TW rules!

John

I have the boards designed but I don't have any pics. What you have should work. They should be in in a couple of weeks and I will post some pics when I get them in. I just wonder how hard it would be to work on if you had to replace a mosfet or zener or something with it mounted under the PS board..

[kineteks]

RE: under PS board placement.. good point & the extra knob kinda blows the stealth thing anyway
I was just looking for more mounting options and a more TW "look", goofy huh? I made a couple of extra boards so I can just swap 'em out if a component goes....
I'll definitely get some of the new cathode bias units though.....

j

[UR12]

RE: under PS board placement.. good point & the extra knob kinda blows the stealth thing anyway
I was just looking for more mounting options and a more TW "look", goofy huh? I made a couple of extra boards so I can just swap 'em out if a component goes....
I'll definitely get some of the new cathode bias units though.....

j

The new little board I have for cathode bias is only about 1" square and it has all the components mounted on it including the pot. Basically if you have a place to mount the pot you will have room for the whole board and pot.

[sst4270]

I've been following this thread because I'm about 2 days away from firing up a 6V6 express combo with VVR.

I think that Kineteks will be in trouble if he uses that particular VVR circuit on an Express as the Express is fixed bias circuit.

Just my $0.02.

Dana, did you get my PM?

BTW Dana & Darrin, the liverpool amp I built with VVR has been getting daily use for about a year now at various power settings. Zero issues.
Zero complaints only praises from its owner.

Steve

[UR12]

I've been following this thread because I'm about 2 days away from firing up a 6V6 express combo with VVR.

I think that Kineteks will be in trouble if he uses that particular VVR circuit on an Express as the Express is fixed bias circuit.

Just my $0.02.

Dana, did you get my PM?

BTW Dana & Darrin, the liverpool amp I built with VVR has been getting daily use for about a year now at various power settings. Zero issues.
Zero complaints only praises from its owner.

Steve

John is trying to set up the VVR without the buffer circuit for the Bias and just use a dual pot to track the bias along with the original TW bias circuit and adjustment. Basically the same setup I used on the Lil Devil.

I have a few Liverpool combos out there also and I have only had complements also. It is really a great little amp.

[Krinkle]

BTW Dana & Darrin, the liverpool amp I built with VVR has been getting daily use for about a year now at various power settings. Zero issues.
Zero complaints only praises from its owner.

Steve

Thanks Steve. I have had a lot of experience with Power Scaling but wanted to do away with the exta transformer. I'm about a week away from finishing my Express build. Barring any mistakes or issues, I will play it for a while to try to get a feel for what it should sound like without going deaf, and then install Dana's board. I can already see that it should be fine.

[John_P_WI]

Barring any mistakes or issues, I will play it for a while to try to get a feel for what it should sound like without going deaf, and then install Dana's board. I can already see that it should be fine.

WHAT??? You can still hear after that 100 watt Metro build!!!

Take care,

John