AC30...master volume or VVR, or ???

[dehughes]

Hello again,

In reading posts about various ways to get big amps going at lower volume levels, I've come across this VVR thing. Sounds interesting. Right now I have what is essentially an AC30 but with a PPIMV, and while it is OKAY (pretty good actually...), I'm wondering if any of you have tried other reduction techniques that have yielded good results with an AC30-ish creation. I don't necessarily want to create preamp distortion at lower volume levels (as it does now...) so much as capture the essence of the amp as a whole, but at lower volume levels. Hence my interest with the VVR. I'm a guitar-into-amp player, no pedals, so I like the amp to be alive and kicking, without getting me kicked out of wherever I'm playing it.

Suggestions are greatly appreciated...

[Tubetwang]

I don't use any pedals either as it creates more noise. My only amps left here are my Express and Liverpool. All other amps have been sold.
I like simplicity.

Not fond of MV and i have built some attenuators..no cigars.

Dana's VVR2 works great for me.

Comes with good instructions and is most affordable.

Dana and his brother Plexi are both respected pillars of the DIY Amp community and have been helping mui newbies like i for many years...

Grab one while you can!

Not selling anything...only a happy guitar player enjoying life.

Major Twang

[dehughes]

Cool. Thanks for the info. I've been reading up on the VVR and it sounds like it would work well in my AC30 creation. I think I have room for a non-PCB assembly in there....don't know about the PCB unit. Probably so, though. I'd like to not use a PCB if I can, as I have lots of space and terminal strips lying about...so really I just need the parts and a good schematic. Would I contact Dana for that, or is there some sort of website?

[Blindog]

Would I contact Dana for that, or is there some sort of website?

Yep, you're already on it

http://ampgarage.com/forum/viewtopic.ph ... +schematic

Mark

[Deric]

I have a MV and VVR in a Trinity TC-15 which is kinda-sorta an AC15-ish thing. The MV is good for crunch at lower volumes but the VVR works great for keeping the cranked vibe at a lower volume.

[dehughes]

I have a MV and VVR in a Trinity TC-15 which is kinda-sorta an AC15-ish thing. The MV is good for crunch at lower volumes but the VVR works great for keeping the cranked vibe at a lower volume.

Yeah, see, that's what I want...the cranked vibe at lower volumes.

Can anyone speak to an attenuator (Airbrake?) as being more or less desirable than the VVR for such a purpose?

[Deric]

I have an AirBrake and have compared it to the VVR in the same amp. While both sounded quite good, the VVR sounded better to me at higher levels of attenuation.

[dehughes]

I have an AirBrake and have compared it to the VVR in the same amp. While both sounded quite good, the VVR sounded better to me at higher levels of attenuation.

Cool...thanks so much! Anyone else?

[dehughes]

Bump for the sake of curiosity...

[bcmatt]

I bought a couple of VVR units off of Dana for some builds.
IN my DC30 clone, I just used the basic circuit with terminal strips (replacing the master volume which I was never satisfied with). I am very happy with it. I often use it to attenuate down to about 9 or 10 o-clock on the knob and it does seem to give the same great sound as being cranked while being much quieter. When I go lower, the sound is not bad, but starting to get a bit fizzier and thinner. Any playing in public would not require any lower volumes than that anyways, because that has got to be pretty low voltage already and quite reasonable in volume.

I also have a weber mini-mass from before. It's not bad either, but the VVR seems way easier and smoother once it is installed, (as well as being less than half the price). VVR is way more convenient to use too. So, I am a big fan of VVR and Dana. I wouldn't hesitate to use one in every cathode biased amp that I get my hands on. This is because they use the simpler circuit and you can fit it anywhere and no heat sink is needed. I'd also consider the VVR2 for fixed biased amps as well, depending on if I feel it could benefit from attenuation.

So, ya, it is my preferred method of attenuation so far, by far.
I will be using them in the Express and Liverpool and T-Rex I am building starting next week. It's already decided and I have the boards here from Dana still waiting for me.

[UR12]

Dang Guys......Thanks so much for the compliments. It makes me very happy to hear everyone has found the VVR usefull.

Dehughes

Just shoot me a pm if you need a board or have questions or anything. There should be enough info posted here for you to incorporate the VVR in a AC30 without having to purchase anything from me, but If you need a kit I have them in stock. I have personally installed the VVR in my Liverpool and a Rocket so the implementation should work just fine in a AC30 as they share some commonality.

[morcey2]

I have an AirBrake and have compared it to the VVR in the same amp. While both sounded quite good, the VVR sounded better to me at higher levels of attenuation.

Cool...thanks so much! Anyone else?

Same situation (18-watt Lite IIb w/ VVR and airbrake). Same result. The airbrake is definitley one of the better attenuators out there, but VVR is much more betterrer.

Matt

p.s. And Dana is THE man.

[bcmatt]

I have a question, that I've been waiting for the answer to appear to on this board eventually. I may just end up emailing you about it Dana, but maybe others could benefit.

I am just curious about the whole heat sink process for amps larger than about 30 watts.

I'll be using your fixed bias VVR2 board for an Express build, but I am wondering how you would install the mosfet with a heat sink. Should the mosfet be right against the heatsink (separated only by the clear plastic thing), or can I just mount the mosfet to the chassis floor and have the heatsink on the other side of the chassis against that point on the chassis? I guess I am just asking if I should be cutting a square mosfet sized whole in the chassis or something.
What other methods have been used? I have a stack of heat sinks that I rescued from inside computer towers that are roughly baseball sized (but not nearly as round of course)

Does anyone have pictures of how they did the heatsink with VVR thing?

Do you need some sort of heat conducting paste or something too? I am pretty clueless about the whole heatsinking thing and what works effectively.

[UR12]

I have a question, that I've been waiting for the answer to appear to on this board eventually. I may just end up emailing you about it Dana, but maybe others could benefit.

I am just curious about the whole heat sink process for amps larger than about 30 watts.

I'll be using your fixed bias VVR2 board for an Express build, but I am wondering how you would install the mosfet with a heat sink. Should the mosfet be right against the heatsink (separated only by the clear plastic thing), or can I just mount the mosfet to the chassis floor and have the heatsink on the other side of the chassis against that point on the chassis? I guess I am just asking if I should be cutting a square mosfet sized whole in the chassis or something.
What other methods have been used? I have a stack of heat sinks that I rescued from inside computer towers that are roughly baseball sized (but not nearly as round of course)

Does anyone have pictures of how they did the heatsink with VVR thing?

Do you need some sort of heat conducting paste or something too? I am pretty clueless about the whole heatsinking thing and what works effectively.

I guess that is a good question. A lot of it really depends on the chassis you are using, how thick it is whether it is made of steel or aluminum. I am using a pretty thick chassis for my express builds and haven't found the need to add a heat sink. The chassis does a fine job on it's own. I f you are building a conventional express with Cherry cab the cab is open in the back and you get plenty of ventilation. If you had a amp that was producing the same wattage on a steel chassis that was all buttoned up in a head cab with a back and ventilation screen then you may need to add the extra heatsink. You really need to look at each build to determine if a extra heat sink is needed or not. Try it with out one and see how hot it gets. If you can't keep your hand or finger on the chassis on the other side of the mosfet then you need to add a heat sink.

If you decide you need one then the best way to go is to bolt the mosfet to the chassis and attach the heatsink on the other side (outside) of the chassis above the mosfet. That way you get the benefit of using the chassis AND the heat sink to cool the mosfet. The mosfet will dump heat into the chassis and the heatsink will pull the heat from the chassis and disipate it into the surounding air. There is no need to cut a hole in the chassis and attach the mosfet directly to the heat sink. You can use the thermal paste between the chassis and the heatsink. The paste is usually used for devices that bolt directly to a heatsink/chassis and doesn't require the insulator. It doesn't hurt to use it with an insulator and I have seen some guys use the paste to hold the insulator onto the mosfet so they can mount both a little easier at the same time.

[UR12]

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