lets ponder yet some more

rockstah · Post by **rockstah** » Thu Feb 02, 2006 5:43 pm

i know i know more about ed - lets ponder... looking at schematic 1959 70-6-11 this is a 1969-1970 amp isnt it? a superlead. now this is the stock spec to my ear that gets me the closest of all stock specs to evh.. now

ed's amp was a 12 series transistion 67-68 amp.
so the amp would have had the lower filtering, shared cathode 820/250u, no bypass on v2a, .1 output coupling, .022 on bright channel - so basically a superbass! not the 1970 schematic ... a superlead in the furthest extreme!... what say you?

Mark

Guest · Post by **Guest** » Thu Feb 02, 2006 9:54 pm

Hey Mark..I didn't bother with this post at the palace for obvious reasons...Man those guys get hostile about EVH.

Wasn't there a post here a week or two ago where someone pointed that very same thing out. Eddies amp was really a Super Bass with the values that were in the circuit?

Star*Guitar · Post by **Star*Guitar** » Thu Feb 02, 2006 9:55 pm

That was me in the last post.

bmf5150 · Post by **bmf5150** » Thu Feb 02, 2006 10:22 pm

im convinced the amp was a 12 series super lead just like master keepers amp.his serial number is very close to eds!

rockstah · Post by **rockstah** » Thu Feb 02, 2006 10:56 pm

Anonymous wrote:Hey Mark..I didn't bother with this post at the palace for obvious reasons...Man those guys get hostile about EVH.

Wasn't there a post here a week or two ago where someone pointed that very same thing out. Eddies amp was really a Super Bass with the values that were in the circuit?

i missed the post... i dont see how though

anyway thats just it though to my ears it sounds more like a later say 69 circuit superlead. look at the 1959 70-6-11 schematic with a 32u in preamp and 100pf fizy cap the .68 on v2a for vh1 and remove that same .68 for vh2 - im not saying that is it so much as im saying out of the gate that stock spec to my ears here playing the instrument gets the closest not only it how it sounds but how it responds ( being aguitar player i can relate somewhat to sound as far as how it feels when they are playing it) anyway blah blah food for thought and maybe someone will try it or have tried that can comment back on it.
Mark

rockstah · Post by **rockstah** » Thu Feb 02, 2006 10:58 pm

bmf5150 wrote:im convinced the amp was a 12 series super lead just like master keepers amp.his serial number is very close to eds!

i dont doubt it was 12 series marshall amp - what i am questioning is the spec of that particular 12 series amp

Star*Guitar · Post by **Star*Guitar** » Fri Feb 03, 2006 8:07 am

The only difference on the 69 of course is the cans on top. ****** said in an old post that the filter caps down below are very important to that tone. Something to do with the field of the tranny needed to be in close proximity to the filter caps.

5150loveeddie · Post by **5150loveeddie** » Fri Feb 03, 2006 3:14 pm

Star*Guitar wrote:The only difference on the 69 of course is the cans on top. ****** said in an old post that the filter caps down below are very important to that tone. Something to do with the field of the tranny needed to be in close proximity to the filter caps.

The flux...........

Bainzy · Post by **Bainzy** » Sun Feb 05, 2006 11:16 am

the flux of the capacitors?

flux capacitors?

...time travel....????

maybe EVH's amp has more going for it than we first thought....

VHoholic · Post by **VHoholic** » Sun Feb 05, 2006 2:49 pm

Bainzy wrote:flux capacitors?

...time travel....????

That's the Secret! The Flux Capacitor....mp3.

5150loveeddie · Post by **5150loveeddie** » Sun Feb 05, 2006 5:04 pm

VHoholic wrote:
Bainzy wrote:flux capacitors?

...time travel....????
That's the Secret! The Flux Capacitor....mp3.

yep the flux capacitor, lol...................

Back to the futur, I love that movie....

It effects the flux in general, the path of the signal, electric signal, I don't know, ask ******......here is a little explanation talking about the flux in one tube operation....

VAlves don't care about plate load....and there is no matching going on in the first place..
The currents go up when the load resistance value on the primary goes down....so you get peak AC currents that may damage the OPT winding..
Four EL34 valves just happen to have the same plate resistance as a single EL34...
A EL34 at the operating conditions in a 100W Marshall will have a plate resistance roughly around 17K to 19K ....a chinese tube will have totally off the wall numbers..
Well in Push-Pull Parallel...each side of the OPT will have 17K /2 and that would be 8.5K plate resistance...then each side of the OPT is in SERIES so that 8.5K + 8.5K goes back up to 17K for the total source resistance for 4 EL34's in push-pull parallel....
A very poor method "rule of thumb" to determine usable plate load of a pentode is to use 1/10 to 1/12 the source resistance....this is in many tube textbooks intended for techs and hobbiest..
Well, 1/10 of 17K is 1.7k ...well, well what a coincidence...that just happens to be what Marshall used...
A single EL34 has a source resistance of 17K BUT only uses HALF the number of primary windings that the set of 4 valves used....so the reflected impedance is the square of the turns ratio...so that means using just one side of the OPT will relect only 1/4 of the impedance seen by the entire primary... SO a single EL34 will see a plate load of 425 ohms...this will produce some high peek AC currents....but since it is only one tube the primary wire should handle it...
If you want to get the plate load up a bit higher to a more acceptable range ...then drop the secondary termination switch to 4 ohms while using a 16 ohm cab or load.. This will then put a 1.7K load on just one side of the OPT, thus better suited for using just a single EL34 valve..
The other concern is that since this is a AB1 amp..you will have a waveform that is assymetrical when using one EL34..this will result in massive amount of even order harmonics from the output stage...
The only draw back is the the DC current is not BALANCED in the OPT and will result in lower inductance and lower flux density headroom, meaning the OPT wil saturate from playing much lower..
An alternative is to put a single EL34 on the other side of the OPT and only connect the DC bias to it's grid and to dissconnect the coupling cap on that side so as to not sendf any AC signal...this way you can cancel the DC in the OPT but still maintain using a single EL34 for the amplification of the audio..

Guest · Post by **Guest** » Tue Feb 07, 2006 7:35 pm

Man I always wanted that amp that blew Michael J Fox though the wall when he stuck a chord. To think, having an amp with all that power...

..

Star*Guitar · Post by **Star*Guitar** » Tue Feb 07, 2006 7:36 pm

Yep..the forum strikes again..that was me in the last post..

erigm · Post by **erigm** » Thu Feb 09, 2006 8:28 pm

Rockstah,

I listened to your latest clips on your website since I hadn't been there in a while. The lastest ones sound awesome! You are getting SO close. It sounds really good man!!!

rockstah · Post by **rockstah** » Sun Feb 12, 2006 4:03 am

erigm wrote:Rockstah,

I listened to your latest clips on your website since I hadn't been there in a while. The lastest ones sound awesome! You are getting SO close. It sounds really good man!!!

im lovin it!