Debate on Eddie's Plexi

[SteadyEddie]

Ben and I were discussing the types of caps used for the .68 cathode bypass. I experimented and found it made a huge difference in attack and tone. I ended up sticking in a mojo dijon (not mustard-like AT ALL. Polypropylene and foil, they are clear, bright and fast) in V1, and a Sozo Vintage in V2. The polypro made notes jump out of the guitar in the upper mids. Techniques like tapping become much easier. I could tell a difference when playing "Panama" when arpeggiating that sus chord. The Sozo in V2 smooths out the sound, makes it nice and pretty.

One cap that Ben and I were both fond of was the CDE DME (1KV) caps. Really tightens up the sound of the amp, less flubby sounding, just nice and open sounding but not harsh. They are polyester film and foil. I'd like to try the El Mencos if I can get my hands on one. Ben sent me an Arco cap but I ended up preferring the CDE.

Edit: Looks like the Arco IS the El-Menco cap. It had an open high end, but was a bit "tubby" sounding in the low end. I'm telling ya, get some of the CDE DME caps from Mouser; you'll like them a lot.

[Ted B]

I ended up sticking in a mojo dijon (not mustard-like AT ALL. Polypropylene and foil, they are clear, bright and fast) in V1 ...

That seems similar, both in construction and description, to a Sprague 715 OD. It's interesting that Mojo would make that mustard reference if they aren't built like a mustard nor sound like one.

One cap that Ben and I were both fond of was the CDE DME (1KV) caps.

I've used those some years ago. Those are metalized polyester caps. I'll have to check them out again, if nothing else, just to gauge how they change the flavor of the amp as opposed to the Sozo Vintage. Are you using these for all signal coupling caps?

[rgorke]

This experience is showing me that its all about the right combination. understand the characteristics of each construction and blend them. Yes, mustards are smooth, warm and musical, polys add sizzle and are on the harsh side. sozos might not be right all by themselves but i'm sure if you noodled enough you could figure out the right cocktail.

you can bet that each cap, both value and construction was chosen for a specific purpose on his amp. Exactly why DF didn't have much of an issue giving out the basic formula. its only part of the equation. Its the very reason why some plexis sounded better than others and all sounded different. it appears that that era only spec'd the value.

i certainly wouldnt expect to buy a few of these and expect to nail the tone.

heck, you could have excessive sizzle and tame it with a prerola cone, or have a mellow amp and add some harshness with blackbacks. its all about the big picture.

This is it exactly!!!! It could be mustards with a different pickup or wood in the guitar or have too much high end and use a 40 ft cable or what have you. One little change can either make things fall into place or completely upset the apple cart.

Having a "chicklet" .68 on V1b and the mylar cap in V2, then a soft PAF pickup or mustards and a Super distortion.

Just when I thought we had it figured out.....

[SteadyEddie]

The mojo dijon is very clear and open but has a little edge to the top end that seems to be characteristic of polypropylene like the 715P. The CDE DME does not sound like Sozo, vintage or standard. It is more open in the mids and focused in the bass and yet not harsh on the high end. Very uncolored caps. I use em for coupling and in the tone stack.

I ended up sticking in a mojo dijon (not mustard-like AT ALL. Polypropylene and foil, they are clear, bright and fast) in V1 ...

That seems similar, both in construction and description, to a Sprague 715 OD. It's interesting that Mojo would make that mustard reference if they aren't built like a mustard nor sound like one.

One cap that Ben and I were both fond of was the CDE DME (1KV) caps.

I've used those some years ago. Those are metalized polyester caps. I'll have to check them out again, if nothing else, just to gauge how they change the flavor of the amp as opposed to the Sozo Vintage. Are you using these for all signal coupling caps?

[YMI5150?]

What's odd to me are the specs on the normal channel components. There is a small interaction, even if they're not officially jumpered. I've got to assume the normal channel was dimed as well which would add some fullness to the bright channel. I hear this on my rig. By itself, it seems way to muddy to ever be useful and I'm tempted to clean it up a bit but am not sure of how much it affects the bright channel's tone. More work to do...

[rgalpin]

in a SL circuit with stock component values, i hear a sweetness that dials in when you put ch II vol at about 3 while plugged directly into ch I (no jumpering) - due to the interaction you are talking about. that sweetness goes away as you dial ch II away from "3" in either direction.

[jnewlyn]

in a SL circuit with stock component values, i hear a sweetness that dials in when you put ch II vol at about 3 while plugged directly into ch I (no jumpering) - due to the interaction you are talking about. that sweetness goes away as you dial ch II away from "3" in either direction.

thank you. I've had so many people argue that ch II does nothing if it isn't jumpered. So not true.

[YMI5150?]

plug into channel II, turn channel II pot to zero, crank channel I pot. if there was no influence you would hear nothing...

[Tone Slinger]

There are still alot of 'turns' to be made considering the Marshall 1959 circuit. Go this way, or that, no go this way 'cause it is this or that, etc, etc. I love hearing what everyone comes up with .

[Ralle]

"untouched except for filter caps and 1 added part which I prefer to keep to myself (Dave knows it well of course too). It is a very minor addition that Jose did giving it a slight bit more bass in the treble channel, when Ed demo'd the amp for me he dimmed every control. The circuit other than that was STOCK.... BUT !! it was not the every day Normal circuit, there were a few oddball parts that Marshall did use from time to time. Not every Marshall follows the schematics.

The 2 non typical parts in this amp contribute to the gain in a very minor way. They were not major parts and the amp Already had the 680n at the cathode of the cathode follower."


1 added part plus 2 none typical parts... adds up to three odd " balls "... right?
Can't be that hard... ones the rest of the stock circut is in the open...
Could a 27k/16 ohm NFB circut in a superlead with split cathods ( 2.7k/.68u ) be considererd as such an oddball?
Or is it a component with a none marshall excisting value?
Maximum NFB in a superlead with split cathods is pretty wierd, if you ask me... BUT it does sound closer to the early EVH ( I've allways stuck to those values )
Here is every reason to want to add more bass in the lead circut...
My two cents is that the gain Eddie had, comes from the preamp section... with a fairly clean power section, cleaning out all the mudd and shit... just basic thoughts...

[Ralle]

plug into channel II, turn channel II pot to zero, crank channel I pot. if there was no influence you would hear nothing...

You'll get the most action if vol II is between 12 aclock and 2 aclock... a sweet spot...

[YMI5150?]

Ralle - I tend to agree with you on the preamp section. its not preamp heavy gain but the type of distortion coming from V1 and V2 is key, of course along with the girth of the power tubes maxed out. the few items that deviate from the standard mustard caps are much less "musical".
also assuming the secret component is the fat cap, from my limited experience, this is key for all early tones BUT depends on the the OT and NFB circuit. My first build that Eric has sports a Marstran 2". it has a natural darkness to it down low that is very similar to a MM 2" with a fat cap. No way to copy his specs and get his tone. more of a guideline.

[Strat78]

Ralle, any luck with the hookup wire search?

[Tone Slinger]

Based on the clips Shannon waxed back in Oct., the 16ohm tap/1998 sounds like a great spec. I had always assumed, based on others EVH clips, that Ed's was of this spec as well. Pretty standard early '68 type spec. Full circle to 2.0's and 2.5's circulated (and widely believed) by some here. Ed's amp, regardless of a variac, since he ALWAY's used the thing, SOUNDED tighter (yet perfect sag) in 1977. Later though, it sounded like it added bottom and headroom, but lost a certain tightness, in later years (replaced tranny again, 4ohm tap etc, etc) ?

1998 style tranny on 16ohm tap,*possibly* el-34's (didnt Strat78 mention this as a possibility). A world tour (1978) would render a performer to REALLY consider tube life and reliability (as well as domestic prices), thus the change to 6ca7.The more gain and compression el-34's deliver, when pushed (as well as slightly softer brown/warmth), along with stock spec 1998 tranny and 16ohm tap sounds right for 1977 Ed. Maybe Ed didnt start using 6ca7's until '78 ?

[Ralle]

Ralle, any luck with the hookup wire search?

I haven't really been looking that hard, to be honoust... I kinda stuck with the ones I had... it it works fine... I just had a week moment back there, where I thought I needed to get the exact right gauges for the wire... I'm sure it's something there, but I'll just leave it till another week day...

About the far cap; that fat cap is not one of the secret components... it's been known fore ages that it was in there from after the first album... Plus it's suppose to be an added part that adds bass in the LEAD channel... not many opptions there...
That's one part... two more to go... and these are stock parts... that not nessacarally adds that much gain to it all but alters it to some degree...
When that has been figurerd out, there's the change of the filter caps ( preamp and screens )... So, unless it wasn't two replacement ( same value ), the famous 12 serie values doesn't fit in here... and by that I mean 2x32 preamp and 16u screens ( two 32's in serie )

It's not that many things to look for, but there's a whole lot more combinations of those named configs; three odd ball parts ( where one of'em is added, the other two is stock )... the change of filter caps... these parts together creates a number of combinations to try out... how many? Somewhere around 10 - 20 different combos ( not sure about the math... )