ATBL and the Variplex

tubez · Post by **tubez** » Fri Feb 29, 2008 10:34 am

Pete,

Good lord!

You win hands down! Beautiful replication of the original recording. That amp is the real deal and your hands well thats another story! See ya over at TGP.

MARCO · Post by **MARCO** » Fri Feb 29, 2008 10:36 am

Variac is used as a huge master volume and can go from normal 110-120v all the way down to a number I cant remember.
Dave Friedman can better explain it. RACKDOCTOR, Dave Phillips also put some clips up of a Variplex up here somehwere. It sounds very impressive and is a convincing EVH for sure.

Hey Pete, You should have used the variac, it might have been eve n better....if there is such a thing!!!

RACKSYSTEMS · Post by **RACKSYSTEMS** » Fri Feb 29, 2008 10:52 am

he did use a regular variac [not the one that comes with the amp] to 90v and it was biased hot while at 90 v Dave

MARCO · Post by **MARCO** » Fri Feb 29, 2008 10:57 am

My fault, didnt see the variac part. Your up early Dave. Do you think the 6CA7's and G12H are a big factor? I would think the Greenbacks would probably sound better.

smzinno · Post by **smzinno** » Fri Feb 29, 2008 11:21 am

Dave, just curious as to how hot is "hot" for the bias ?

RACKSYSTEMS · Post by **RACKSYSTEMS** » Fri Feb 29, 2008 11:37 am

Well this is the thing the amp sounds that good thru the wrong spk,wrong cab with a attenuator. Pete did a lot of work to get it even that close. Now also remember the original had 2 different speakers on it blended. You hear a lot of engineering on the albums its not really what came out of eds amp exactly. As far as the bias variac was at 90v and then it was biased to 50ma which then gives you a plate voltage of 325 to 350 if the power transformer is speced with the right current. Remember these readings are for a 50 watt not a 100 watt. Dave

bmf5150 · Post by **bmf5150** » Fri Feb 29, 2008 12:40 pm

RACKSYSTEMS wrote:Well this is the thing the amp sounds that good thru the wrong spk,wrong cab with a attenuator. Pete did a lot of work to get it even that close. Now also remember the original had 2 different speakers on it blended. You hear a lot of engineering on the albums its not really what came out of eds amp exactly. As far as the bias variac was at 90v and then it was biased to 50ma which then gives you a plate voltage of 325 to 350 if the power transformer is speced with the right current. Remember these readings are for a 50 watt not a 100 watt. Dave

yeah i bet it would sound even better with some pre rola greenbacks...none the less,it nails his tone...

rockstah · Post by **rockstah** » Fri Feb 29, 2008 12:42 pm

so the airbrake was used? So was the amp set to 8 ohms? Or no because this is 50 watt we are hearing?

Dave, I understand the plexi spec of the variplex is what we are hearing. Why was a regular variac used? I thought the variplex has a built in variac.

Good Guest · Post by **Good Guest** » Fri Feb 29, 2008 1:20 pm

Best rendition I ever heard...a little bit of brightness missing in the highs but all in all nothing that takes away from the tone.

What is Ed doing? Here there is an amp that walks over anything he's marketed ...he should have a wall of these "Blankenship Variplex's"...

The production on this clip is first class also.

rockstah · Post by **rockstah** » Fri Feb 29, 2008 1:23 pm

he's trying to sell his amps. That's what the tour is about... Money.

harddriver · Post by **harddriver** » Fri Feb 29, 2008 1:35 pm

Clip sounds great Pete, the 12H30 will be brighter and more efficient than a greenback maybe giving a little more sizzle than the greenback.

At 350DCV plate voltage the amp is biased about 70% dissipation, correct running @50ma.

One question for Dave about the extremely hot bias ie. cranked all the way up into the range where the tubes and OPT can arc over, I was always under the impression the tone can get muddy almost motorboating whereas using too little bias into crossover distortion yields cold/sterile fizzy tone. One forumite did post that with a higher bias is allows the power tubes to distort sooner.

The Variplex sounds great as it always does Dave.

I agree with your take on Ed's engineered sound but he does come close to the album tone in some live boots, Die Laughiing 12/20/77 the Paris 78 show and a few others.

Peter are you running your UREI( I think) mic preamp on this clip like you have used with your 5150III clips if I'm remembering right?

gnugear · Post by **gnugear** » Fri Feb 29, 2008 1:42 pm

That was fantastic sounding. Great amp and playing!

rockstah · Post by **rockstah** » Fri Feb 29, 2008 1:43 pm

50ma is not hot at 325dcv.

.70x 25 = 17.5 / 325 = 53ma

Its not even 70 percent MPD!

At 350dcv he's right at 70 percent MPD if its 50ma

smzinno · Post by **smzinno** » Fri Feb 29, 2008 1:49 pm

I was just about to post the same thing, there's nothing hot about 70 percent diss. in push-pull. even at 350v, 50ma is still quite normal.

smzinno · Post by **smzinno** » Fri Feb 29, 2008 1:56 pm

actually, possible correction (to myself). if the amp was first biased to 50ma, then dropped with the variac, this would appear to be a very hot bias. for example, if the normal B+ was 450-475v then 50ma would be very close to max dissipation. if it then scales down when dropped with the variac, it should still be hot. just sayin ....