VVR in a "beefed up" 5E3 Tweed Deluxe (FINISHED)

[doveman]

I have just purchased a Richter Supra-Luxe head ... beefed up to 30w with 6L6/GZ34. A very loud 5E3 amp ... but it has to get up there to start the magic. While there have been some changes to the amp to handle the extra power, most of the 5E3-ish flavor is maintained ... preamp is the same ... PI is the same ... etc. Very nice work I think. I was considering building a head version but Richter stopped offering the head. Bought this one used ... built by Richter just a few months ago.

[IMG:639:426]http://i104.photobucket.com/albums/m168 ... -front.jpg[/img]

[IMG:639:426]http://i104.photobucket.com/albums/m168 ... d-back.jpg[/img]

I've ordered Dana's (UR12) VVR for Cathode Biased up to 50w units. The head has 4-8-16 option too ... easy to match with my many cabs. The chassis is a bit bigger, so it should be easy to find a place for this on the back of the chassis. Only $32 with shipping ... a very reasonably priced mod I think.

[IMG:450:298]http://i104.photobucket.com/albums/m168 ... rTweed.jpg[/img]

The one question I would like some input: Seems like some builders control the whole amp and some just the power amp. I have been thinking the whole amp method is where I'm heading. Obviously, I will be asking Dana via email (if he doesn't answer here).

Hoping this will be a sweet mod.

[Gee]

VVR works well in a 5E3 Deluxe when you scale the whole amp. It is difficult and requires an MV if you scale just the PA.

[eazilyled]

I installed a VVR on my 5F1 clone, believe it or not. It worked out really well regulating the whole amp. I know that a 5F1 is completely different from a 5E3, however.

The VVR instructions say that you need to add a master volume if regulating just the power section, meaning you would have to find homes for 2 extra pots on your control panel(s) (VVR + master volume).

One of the pot(s) could possibly go where your standby switch is, if you replace the power switch with one of those Carling Off/Standby/On Switches.

These links seem to indicate that regulating the whole amp on a 5E3 worked out well:
http://yeomansinstruments.blogspot.com/ ... tions.html
http://www.tdpri.com/forum/archive/inde ... 38554.html

Good luck!

[doveman]

Sounds like I'm on the right track with the "whole amp" approach.

I also have one other question: Would there be any advantage to getting a heat sink? I know attaching it to the chassis may be enough but if they make one for this particular component, would it be worth adding? If so, anybody know a mouser part number for the right sink ... if it exists?

Have not heard from Dana yet ... hope he got my order and paypal.

[Zippy]

Have you considered just installing a 5Y3GT and 6V6s???

Does your PT have original spec voltages?

[doveman]

Have you considered just installing a 5Y3GT and 6V6s???

Does your PT have original spec voltages?

No ... this guy is beefed up on purpose. I wanted a 5E3 that was easy to gig with ... this one is loud enough. But I'd still like to be able to bring it under control at lower levels.

I built a Brown Note D'Lite 22/33 that I run with 6L6s that has a really nice master volume that does just that ... really well. The only thing is a MV works well on that amplifier since not much of the distortion comes from the power amp. I think most of the break up on this 5E3 Supra-Luxe amp comes from the PI and the power tubes.

I have found a lot of guys on the forums so far who have had good luck with this VVR on both a 5E3 and a higher power 5E3 ... so I'm feeling pretty confident that this will be a really nice mod. Being able to dial it down and then back up to the 30w range with one knob and not changing the tubes would be sweet.

[Structo]

Great looking Deluxe Ken.

I've been itching to try a VVR myself.

Just need to find the victim first.

[Zippy]

Have you considered just installing a 5Y3GT and 6V6s???

Does your PT have original spec voltages?

No ... this guy is beefed up on purpose.

Being able to dial it down and then back up to the 30w range with one knob and not changing the tubes would be sweet.

"Beefed up" can mean that it has greater current handling capacity at original voltages. If that is the case, you can run the original tube complement (with probably enhanced bass response). Cathode-biased makes it pretty much plug-and-play regarding swapping three tubes.

I get that VVR has its appeal to some people and works well for their application.

G'luck!

[doveman]

"Beefed up" can mean that it has greater current handling capacity at original voltages. If that is the case, you can run the original tube complement (with probably enhanced bass response). Cathode-biased makes it pretty much plug-and-play regarding swapping three tubes.

I get that VVR has its appeal to some people and works well for their application.

G'luck!

Yeah ... I see what your saying. A lot of people don't like MV amps but I love them. So the VVR might appeal to me too.

To expand on my "beefed up" comment: The builder (Sara Richter - seems a really nice person) shared the following with me when I asked her about the differences between a 5E3 and the Supra-Luxe:

"There are a few things that need to happen for a 5E3 to work properly as a Supra-Luxe. First of course you need a correct output transformer, then you need a power transformer that provide a minimum of 200ma on the HV tap. With the transformer in our Supra-Luxe, 325-0-325 @ 200ma and a GZ34 rectifier you get around 460V at the anodes. Being cathode biased you also need a minimum of a 20W cathode resistor of the correct value. Anything less than a 20W wire wound will overheat and ultimately go open. ... the original prototype had a 10W that failed after a fairly short beta run. Running these higher voltages it is also important to add screen resistors, no sense ruining a matched pair of Winged =C= outputs. The stock PI is a big part of the 5E3 ... "

My guess is I would fry me some 6V6s

[Structo]

Have you visited the Richter forum?

They talk about VVR and other things about the Supra.

http://richteramplification.com/board/v ... bb64001f96

EDIT:
I see you have been there.

[doveman]

Yeah ... try to ask around everywhere ... seems to be working out for me so far. If you ask enough smart people (including this group) you will have a good chance at success. A couple of days ago I did not know squat about VVR or power scaling. Actually, I imagined it would be rather expensive. So just goes to show ... you never know until you ask.

[eazilyled]

I also have one other question: Would there be any advantage to getting a heat sink?

The instructions say that between 30 and 50 watts you need to add some kind of heat sink for the mosfet, so at 30 watts I guess you are on the borderline.

You could always install and see how hot the chassis gets with a view to adding a heat sink if necessary?

I'm not sure which heat sink would be best, but the mosfet that comes with the kit is a NTE2973 if that's any help.

[Colossal]

I also have one other question: Would there be any advantage to getting a heat sink?

The instructions say that between 30 and 50 watts you need to add some kind of heat sink for the mosfet, so at 30 watts I guess you are on the borderline.

I'm not sure which heat sink would be best, but the mosfet that comes with the kit is a NTE2973 if that's any help.

The easiest heat sink (and free too!) is the chassis. The mosfet can be mounted to the chassis with the padding material (included with the kit) which physically separates it from the chassis while conducting heat. The chassis barely gets warm in this configuration and is excellent at dissipating heat.

If you mount the VVR board parallel to the chassis, you can solder the mosfet directly to the board and bend the leads at 90deg such that the mosfet contacts the chassis that way. Or, if you mount the board perpendicular to the chassis plane, you can also attach 3 wires to the mosfet to locate it to any point that is convenient, "tethering" it to the board. Both methods work very well. Be sure to heat shrink any exposed contacts on the legs of the mosfet.

Check [url=hhttp://ampgarage.com/forum/viewtopic.php?t=5182&highlight=vvr]this[/url] post for detailed installation shots as well as heatsink options.

[FYL]

The easiest heat sink (and free too!) is the chassis. The mosfet can be mounted to the chassis with the padding material (included with the kit) which physically separates it from the chassis while conducting heat. The chassis barely gets warm in this configuration and is excellent at dissipating heat.

If direct chassis mounting can be OK in small amps, you should always use a dedicated heatsink for larger models, say anything above 30 watts or so using an aluminum chassis, and you must always use a dedicated heatsink for 20-watt plus amps using a steel chassis. Unless you don't care about reliability and love to change dead silicon, of course.

BTW, if the chassis only gets warm maybe it's because it doesn't properly conduct heat.

Thermal conductivity (the higher, the better)

Steel and stainless steel: app. 12 to 80 (lower for SS, higher for std)
Aluminum : app. 120 to 230 (most alloys are in the 120 to 180 range)
Copper : app. 400

[doveman]

I have a 30w amp with an aluminum chassis. So I'll start with the chassis as the heatsink - looking like picture I posted in the first post. Thanks.