my old new alum chassis plexi build

rockstah · Post by **rockstah** » Mon Apr 09, 2007 11:47 pm

here is my original first metro alum chassis that i decided to build up with Georges Dagnall clone OT.

it sounds fucking great!

metro dagnall clone OT
metro dual tap pt
mercury 3h (mar100c) choke

see if i can some clips up of it soon.

Mark

harddriver · Post by **harddriver** » Tue Apr 10, 2007 1:03 am

Are those dual 22uf/450V BC from George in your preamp filtering? Close enough to 16uf for you?

You just running the 80% taps? Just trying to decide if I want to shoehorn the 16/16uf F&T in there or not or just go with the 32/32uf provided.

Is it George's 1.5" dagnal clone? How does it compare to the ****** trannies?

rockstah · Post by **rockstah** » Tue Apr 10, 2007 1:18 am

harddriver wrote:Are those dual 22uf/450V BC from George in your preamp filtering? Close enough to 16uf for you?

You just running the 80% taps? Just trying to decide if I want to shoehorn the 16/16uf F&T in there or not or just go with the 32/32uf provided.

Is it George's 1.5" dagnal clone? How does it compare to the ****** trannies?

correct - BC 22u caps - close enough to 16u i think.

running the low tap(400dcv) at the moment.

u could put a dual 16 like this too.

as far as this OT goes it is Georges 1.5". i think i like it better than ****** - hell i think this amp sounds better than my merc amp!.. but the jury is still out on it. actually lemme play it for a few days. ill let ya know.

Mark

Flames1950 · Post by **Flames1950** » Tue Apr 10, 2007 7:33 am

Nice stuff. Now if only they were small enough to replace the POD on the flight to the gig.

rgalpin · Post by **rgalpin** » Tue Apr 10, 2007 8:29 am

rockstah wrote:
harddriver wrote:Are those dual 22uf/450V BC from George in your preamp filtering? Close enough to 16uf for you?

You just running the 80% taps? Just trying to decide if I want to shoehorn the 16/16uf F&T in there or not or just go with the 32/32uf provided.

Is it George's 1.5" dagnal clone? How does it compare to the ****** trannies?
correct - BC 22u caps - close enough to 16u i think.

when you use 2 22u caps like that in the preamp do you consider that to be 22u preamp filtering? i am confused about how the preamp cap is wired to the board because i have always had mine mounted on the chassis under the board so i can't see how it is wired and component graphics rarely show this wiring clearly. what is the preamp cap wired to? why are there 2 of them? they must be in parallel because you can't wire a 2 sided can in series right - i need some help understanding... i'll trade somebody an A/B clip of 32u vs 16u screen filtering for some knowledge about the preamp filtering!

jbzoso2002 · Post by **jbzoso2002** » Tue Apr 10, 2007 10:19 am

HELLO ROCKSTA I NOTICED YOU HAVE NO BRITE CAP ON
VOL I , IS THAT STOCK? MINE IS A LITTLE BRITE AND I
HAVE A 250 PF. IM THINKING ABOUT CLIPING IT.

JIMMY

wdelaney72 · Post by **wdelaney72** » Tue Apr 10, 2007 10:51 am

I never use bright caps.

rockstah · Post by **rockstah** » Tue Apr 10, 2007 11:53 am

if u look at the pic long enough you will see that the preamp cap on your amp is two caps inone just like on and earlier amp like mine. u have a dual cap. i used two.

you will also see how each 16u or 22u or 32u of a dual cap is for the first two stages.
on my amp the cap on the left is for the first input stage and the cap on the right is the second gain stage.

your amp, the later 69 style hits those two stages the same its just wired on the board slightly different.
the two 10k in the middle of the board are in a slightly differnet position but wired the same.

using two caps like i did or one dual cap is the same thing.

as well like any other electrolytic cap (thats not a bypass cap )the preamp cap is there to filter the b+ ripple.

and yeah i don't use bright caps.

Mark

rgalpin · Post by **rgalpin** » Tue Apr 10, 2007 12:29 pm

thanks - that helps a lot.

v1 -> plate resistor's path to ground is through one side of the preamp filter cap.
high freq flow more easily through the cap, making it a high pass type filter.
the larger the cap value the lower the cutoff freq.
so, a higher filter cap values let's a wider range of freq go to ground - the higher the cap the deeper the cut.

that's the way i see it from here anyway...

rockstah · Post by **rockstah** » Tue Apr 10, 2007 12:33 pm

kewl man - i hear the preamp cap like the screens or the mains caps - it isnt so much a tonal thing as it is more of a looser or tighter thing. tighter bass stays together. looser it falls apart easier.
again as with all them electroyltic caps they filter B+. they arent tone bypass caps.

rockstah · Post by **rockstah** » Tue Apr 10, 2007 2:23 pm

here is a clip; http://forum.metroamp.com/viewtopic.php?p=109337#109337

Riscchip · Post by **Riscchip** » Tue Apr 10, 2007 7:57 pm

Killer stuff as always my friend. Very nice.

rockstah · Post by **rockstah** » Tue Apr 10, 2007 8:39 pm

this metro dagnall is killer - i think i like it better than the merc OT.

bluze81 · Post by **bluze81** » Tue Apr 10, 2007 8:58 pm

Mark I have the dagnall ot, in my 12000 Metro build, but I dont have anything to compare it to, so you really like it better than the mercury output transformer?

Flames1950 · Post by **Flames1950** » Tue Apr 10, 2007 9:16 pm

bluze81 wrote:Mark I have the dagnall ot, in my 12000 Metro build, but I dont have anything to compare it to, so you really like it better than the mercury output transformer?

Thought that looked like the Dagnall clone in there....no sticker to go by, just the 1.5" core. Not to hijack, but I'd like to play your amp one more time before I send it back Steve.........the Dagnall clone sounds killer in there!!!