Thx Dogears

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Bob-I
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Thx Dogears

Post by Bob-I »

I went to Scott's house yesterday to screw around with my 100 watt BM. This amp has never felt or sounded right to me. I've been concerned that there was something major wrong, like a bad OT or filter caps.

Scott plugged in and in 10 seconds said "something's wrong". He adjusted the dropping string to get the correct voltages on V1 and V2, adjusted the trimmers, lead dress, experimented with tubes, cables to the D-ulator.

In a word, Wow, this amp has never sounded so good. I haven't had a chance to crank it at home, but even at low volumes the buzzyness is gone, the highs are rich and full, lows tight, mids complex.

Now I've got to make up some better cables for the D-ulator and a parallel by-pass for the Quadraverb.

On another note, we testing my Boogafunk cab with a reconed EVM12L. It simply doesn't sound good. I don't know if it's the cab or the recone job (my first attempt at this) but it was nasal and thin. We compared to an old EVM12L in a Hermida cab, night and day.

Thx Scott.
pinner
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Re: Thx Dogears

Post by pinner »

Yep, Scotty is the man!!!!! Got my amp singing!!!!

Bob, it was great to see you again and your amp was smokin!!!
Impressive build!!!
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Bob-I
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Re: Thx Dogears

Post by Bob-I »

pinner wrote:Yep, Scotty is the man!!!!! Got my amp singing!!!!

Bob, it was great to see you again and your amp was smokin!!!
Impressive build!!!
Thx, great seeing you too, we gotta get together more often.

That tone it was all Scott's doing, sounded like junk before his magic hands.

Also great meeting Scott's wife interesting lady and kids. Next time I'm sticking around for Sushi 8)
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butwhatif
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Re: Thx Dogears

Post by butwhatif »

what v did you settle on for v1 and v2?
hitchcaster
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Re: Thx Dogears

Post by hitchcaster »

very cool... what did he change on the lead dress that made it "right"?
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butwhatif
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Re: Thx Dogears

Post by butwhatif »

the lead dress, esp on v2/2 can be very critical
dogears
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Re: Thx Dogears

Post by dogears »

Hi guys,

Bob's amp is a Bluesmaster. I tweaked the hrm stack and trigger to smooth things. He had the stack set more for what a skyline hrm would want. I settled on mids of 4.45k and not the 10k he had. Bass down to 73k from 500k. Treble about 40% up. Trigger at 20k to ground. He was at 24k.

He had a hot 80s Chinese square getter in v2. Real sizzle. I put in some nice gained long grey plate GEs. Balanced PI. I tweaked the trimmer with Bob listening. He noticed even small 1mm moved make a difference. We adjusted it for max bloom and openess with no thuddy bass.

The lead dress was not a biggie aside from a few anamolies. Nothing secret. Just good practice like no live screen resistor leads touching plate leads. :D

Bob had tacked a 22k across the 15k dropper on v2. He had 225v there. I just undid it. He had 180v on v1 and 208v on v2 after.

Sounded great btw.
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Bob-I
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Re: Thx Dogears

Post by Bob-I »

dogears wrote:Hi guys,

Bob's amp is a Bluesmaster. I tweaked the hrm stack and trigger to smooth things. He had the stack set more for what a skyline hrm would want. I settled on mids of 4.45k and not the 10k he had. Bass down to 73k from 500k. Treble about 40% up. Trigger at 20k to ground. He was at 24k.
Thx for posting the numbers Scott, now I don't have to open it up to measure
He had a hot 80s Chinese square getter in v2. Real sizzle. I put in some nice gained long grey plate GEs. Balanced PI.
I was doing so much tube subbing that I simply gave up and stuck that throw away tube in.

The PI we settled on was the RCA I had in V2, found in the basement of a house a friend bought a few months ago.
I tweaked the trimmer with Bob listening. He noticed even small 1mm moved make a difference. We adjusted it for max bloom and openess with no thuddy bass.

The lead dress was not a biggie aside from a few anamolies. Nothing secret. Just good practice like no live screen resistor leads touching plate leads. :D

Bob had tacked a 22k across the 15k dropper on v2. He had 225v there. I just undid it. He had 180v on v1 and 208v on v2 after.

Sounded great btw.


The 225 was way above what I measured at home with other tubes. Funny that I had to use the 22k to get the voltages in line, but with good tubes the voltages fell right in line with the precision PS string.

Scott wasn't thrilled with my heaters. I ran parallel copper rods ala Soldano. Very clean and quiet but Scott was concerned that the plate and cathode leads were too close to the heaters, he bent the rods a few mm away from the leads and redressed them out. He also found a plate lead touching a screen resistor. Must've happened when I moved the grid stoppers.

On another note, I put the EVM12L into a Coyote cab and the nasalness is gone. I'm going try a different speaker in the Boogafunk, somehow the EVM just isn't working. The best tones at home so far is with a Tonker or a 2x12 with WGS V30 and Brittish lead.
BobW
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Re: Thx Dogears

Post by BobW »

Bob-I, how much insulation do you have in the Boogafunk (806) cab? I minimized mine down to just a thick felt on the back and the sides only. It really opened up the tone.
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Bob-I
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Re: Thx Dogears

Post by Bob-I »

BobW wrote:Bob-I, how much insulation do you have in the Boogafunk (806) cab? I minimized mine down to just a thick felt on the back and the sides only. It really opened up the tone.
Interesting. I didn't change what they put in it so there's a lot more than you have. I'll give that a try.
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Bob-I
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Re: Thx Dogears

Post by Bob-I »

BobW wrote:Bob-I, how much insulation do you have in the Boogafunk (806) cab? I minimized mine down to just a thick felt on the back and the sides only. It really opened up the tone.
I ripped out the 3" insulation Boogafunk had in the cab (that's the EV spec) and replaced it with a thin layer of stuffing on the back only. It still seems boxy sounding, but I'll reserve judgment until I get it in a bigger room.
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