VVR in 50 watt modded ceriatone

[Richie]

I thought i'd post these.. this amp is a modded ceriatone,made more like a concorde. Running about 50 watts.. and uses the VVR scaling as bias tracking. Works great. I'm going to install a heat sink on the side of the chassis. Just to keep things cooler. I can crank it from full blast down to a very low volume..and the bias tracks prefect.Works great.

[NitroLiq]

Thanks for posting that, Richie. Looks like a tight fit. Where are you putting the heatsink?

[Richie]

on the side of the chassis. It looks like a tight fit, but its a perfect spot on this amp. The creiatone chassis was a JTM,and it didn't have or use the ground switch..so the hole was in the chassis for it already. And the side of the chassis worked perfect for mounting the board,and keeping the control mounted to the board.

[Lonely Raven]

I so need you to build something like that for me. I'd like that sound, but at more reasonable volumes...

[nickt]

I thought i'd post these.. this amp is a modded ceriatone,made more like a concorde. Running about 50 watts.. and uses the VVR scaling as bias tracking. Works great. I'm going to install a heat sink on the side of the chassis. Just to keep things cooler. I can crank it from full blast down to a very low volume..and the bias tracks prefect.Works great.

Ha ha ha - just proposed putting my (soon to arrive) VVR exactly where you've done it Dana thought it was not a good idea

... might wait until I'm holding it in my hand for a final decision - should be here this week. I've got an Allynmey chassis so dimensions might be different. Thanks for posting

[bigmik]

is that the kit from dana{ur12}?,I read over on 18 watt that he would be offering kits for sale when he finished the instructions.are they ready yet and does he have his fixed bias kit finished

[Richie]

i think he has most of it done,as for the instrctions and boards made, and sent out quite a few to some people. i think hes waiting on an order of mosfets to come in.
I don't think of it as a kit.. but its just a board and few wiring changes,and a couple things needed or added if you scale the whole amp etc.. All very simple.. So simple a cave man can do it
Like anything, if installing it into an existing amp, you have to find a good spot to mount the board,and control. If you were building a new amp, you could allow for the section to put it in the amp,which would be much easier.
This amp is running KT88s, and its putting out quite a bit of power. I just wanted to show that the VVR will work in an amp that is similar.
I've used the cathode biased VVR in quite a few amps,18s and 36 watters. This was the first amp i used it in that is not a cathode biased amp.

Richie

[UR12]

Ha ha ha - just proposed putting my (soon to arrive) VVR exactly where you've done it Dana thought it was not a good idea

... might wait until I'm holding it in my hand for a final decision - should be here this week. I've got an Allynmey chassis so dimensions might be different. Thanks for posting

Nick

One problem with the TW style amps I was talking about was mounting it on the side panel where the bolts that come through the capture nuts may present a problem with clearance where as on this amp the lip of the chassis turns out instead of in and the chassis bolts are on the outside of the chassis. As long as you position it so there isn't a clerance problem with the chassis bolts you should be good to go. The other problem I can for see with the side panel mounting in a TW is that if you use a nice Cherry TW style cab, the chassis is right up against the side of the cab and you will be transfering heat to the wood which might cause some discoloration of the wood after years of use. If you are mounting the chassis in a non traditional cab like a marshall head or something then there would be no problems mounting it to the side panel if there was plenty of clearance.

[drhulsey]

..and the bias tracks prefect.Works great.

Thanks for sharing this. I am very excited about trying this device. Your brother has given us something special with the VVR

[nickt]

One problem with the TW style amps I was talking about was mounting it on the side panel where the bolts that come through the capture nuts may present a problem with clearance where as on this amp the lip of the chassis turns out instead of in and the chassis bolts are on the outside of the chassis. As long as you position it so there isn't a clerance problem with the chassis bolts you should be good to go.

Hey Dana - no issue and no critisism intended - I'm totally winging this TW. My little peanut brain only works when I move things round - paper design is not my forte these days - I suspect the ceriatone chassis is different to Allyn's WRT the bolts in any case - just a funny coincidence where Richie mounted the VVR.

The other problem I can for see with the side panel mounting in a TW is that if you use a nice Cherry TW style cab, the chassis is right up against the side of the cab and you will be transfering heat to the wood which might cause some discoloration of the wood after years of use. If you are mounting the chassis in a non traditional cab like a marshall head or something then there would be no problems mounting it to the side panel if there was plenty of clearance.

Cherry cabinet? I wish Cherry, Birch, Maple, Walnut in Oz? Its easier to buy high quality Australian wood via a US web-site and have it shipped back than finding it here in Oz.

Anyway my plan was to mount the FET on a thick piece of aluminum and so spread the heat out. The lamp hole on the chassis is still a good place for the pot but I suspect I'll end up putting the FET and board elsewhere (possibly separately elsewhere). That whole end of the chassis has trannies over most of it so isn't a good site for any heat sinking.

BTW have you had any issues if the various leads are long(ish)? I was thinking of putting a 0.1u after the VVR but just before the 1K dropping resistor to dump any HF pickup/radiate to ground.

cheers
Nick

[castor]

Very Good... can you record some samples just to have an idea of the overall sound?

castor

[UR12]

Very Good... can you record some samples just to have an idea of the overall sound?

castor

If you are a member of the SEWATT forum there is a member there(Chad) who did a clip of a SE amp he built and included one of the VVR with it cranked way down. You can listen to the clip and the 4th part of it is the VVR cranked all the way down with about 38v on the tubes. He has the whole amp regulated and not just the power section. Listen to it once to get a reference of how much the vol has dropped and then go back and listen to it again and crank up your computer speakers to hear the tone and sustain at the low vol. It should give you an idea of what the VVR is all about.

http://www.sewatt.com/node/16930