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Author Topic: New build 6080 red plating (false alarm)  (Read 654 times)

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Offline grosen

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New build 6080 red plating (false alarm)
« on: December 03, 2020, 01:14:06 PM »
Hi all.  My new C2A has been up and running without a hitch for about a week.  Just now I noticed that the 6080 seems to be red plating. Haven't put the amp back on the bench yet, but thought I'd ask where the problem is likely to be.  Thanks in advance.
« Last Edit: December 05, 2020, 10:09:20 AM by grosen »

Offline Doc B.

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Re: New build 6080 red plating
« Reply #1 on: December 03, 2020, 01:38:11 PM »
First step is to check your voltages. Watch that tube when you do, don't run it for more than a minute or so.
Dan "Doc B." Schmalle
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Bottlehead Corp.

Offline grosen

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Re: New build 6080 red plating
« Reply #2 on: December 05, 2020, 04:15:14 AM »
Thanks, Doc.   The voltages look fine, except that

          KregB on the Low Current board is 6.3V, when it should be between 3V and 6V, and
          OB on the High Current boards is 88V on one; 82.5 V on the other, when it should be between 90 and 110V.

Here's the complete set of readings. 

Low current

        Spec       Measured

IA       150          148
OA      60-90       70.6
KregA  3-6            4.5
bRegA  150         148

IB        150         148
OB       60-90      67.1
KregB   3-6         6.3
bRegB  150         147


High Current        D          B

IA          190        186       188
OA         150        147       149
bA             0           .3mV    .5mV

IB              0            .3mV    .6mV
OB          90-110     82.5       88
bB           150           149      149


Offline Paul Birkeland

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Re: New build 6080 red plating
« Reply #3 on: December 05, 2020, 05:43:58 AM »
Can you post a picture of the red plating?
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline grosen

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Re: New build 6080 red plating
« Reply #4 on: December 05, 2020, 06:17:22 AM »
Not sure how to post a pic.  Let's see if this works.

https://postimg.cc/7J405T1j

Offline Paul Birkeland

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Re: New build 6080 red plating
« Reply #5 on: December 05, 2020, 06:19:45 AM »
I don't see any red plating.  I do see a nice hot cathode sleeve, but that's totally normal.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline grosen

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Re: New build 6080 red plating
« Reply #6 on: December 05, 2020, 07:02:17 AM »
That’s great. Thanks. I wasn’t sure, but it looked unfamiliar to me, and like some of the pics of red plating on the web. Good to know it’s normal.

Offline grosen

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Re: New build 6080 red plating
« Reply #7 on: December 05, 2020, 08:37:10 AM »
Bonus pic of amp.  All stock with eccentric paint job and ambrosia maple case.  Thanks to Paul for chiming in so quickly.

Deke609

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Re: New build 6080 red plating
« Reply #8 on: December 05, 2020, 08:42:02 AM »
Very nice! Painting the stock knobs is a really cool touch. I don't recall seeing that before. What kind of paint did you use? 

cheers, Derek

Offline grosen

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Re: New build 6080 red plating
« Reply #9 on: December 05, 2020, 10:06:03 AM »
Thanks.  The knobs and transformer edges are Rustoleum Gloss Enamel red.  The plate and the transformer cover are Rustoleum Oil Rubbed Bronze metallic.

Online johnsonad

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Re: New build 6080 red plating (false alarm)
« Reply #10 on: December 05, 2020, 12:40:43 PM »
That's a nice looking build! 
Aaron Johnson

Offline Paul Birkeland

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Re: New build 6080 red plating (false alarm)
« Reply #11 on: December 05, 2020, 12:48:43 PM »
I like the maple a lot.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man