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Post subject: Re: Vintage Reissue '65 Deluxe Reverb mods?
Posted: Fri Jul 20, 2012 12:29 pm
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Max plate dissipation is 12W according to the TS spec sheet.

http://www.dougstubes.com/6v6gt-tungsol.pdf

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Post subject: Re: Vintage Reissue '65 Deluxe Reverb mods?
Posted: Fri Jul 20, 2012 3:47 pm
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tyronne wrote:
Max plate dissipation is 12W according to the TS spec sheet.

http://www.dougstubes.com/6v6gt-tungsol.pdf


Ok. Yes. They definitely need to be dropped down a couple of mV depending on the plate voltage.

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Post subject: Re: Vintage Reissue '65 Deluxe Reverb mods?
Posted: Sat Jul 21, 2012 7:59 am
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bluesky636 wrote:
Stinger22 wrote:
OK got my new tester in and with a "matched" Tung-Sol 6V6GT set, they both had 26 written on the box got.

409 plate voltage on both
26.4
24.5

Lowered to

25.5
23.8

Shooting for an average of just under 25.

Too hot? About right? Sounds a little cleaner at the lower bias


Well, recognizing that you are measureing cathode current vice plate current so any calculations are a little high and IF your tubes are rated at 14 or 15 watts max, you are right around 70% max plate dissipation.


Can't find a rating on them on the TubeStore website or anywhere. Like I said the were ordered under the "perfect match" thing the do and each box has a 26 written on it.

Never mind just found where Tyronne posted the spec. Played last night and it sound great, but will do the calculation again and "tweak" somemore.

thanks Tyronne


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Post subject: Re: Vintage Reissue '65 Deluxe Reverb mods?
Posted: Sat Jul 21, 2012 8:46 am
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Funny how much lower your voltage is compared to the stock tubes I had, and the JJ's I have in there now. Right now I'm sitting at

22.7 @ 430 and 22.6 @ 430.

And I think I'm going to lower it a little more.

Question, how do you calculate the plate dissipation?

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Post subject: Re: Vintage Reissue '65 Deluxe Reverb mods?
Posted: Sat Jul 21, 2012 8:49 am
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According to this, its a 14 watt tube:

http://www.datasheetarchive.com/indexer ... highscore#

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Post subject: Re: Vintage Reissue '65 Deluxe Reverb mods?
Posted: Sat Jul 21, 2012 8:55 am
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Hou-Tex wrote:
Funny how much lower your voltage is compared to the stock tubes I had, and the JJ's I have in there now. Right now I'm sitting at

22.7 @ 430 and 22.6 @ 430.

And I think I'm going to lower it a little more.

Question, how do you calculate the plate dissipation?


Plate dissipation = plate current x plate voltage. However, most bias probes only measure cathode current and plate voltage. Multiplying those values is close enough and provides a slight safety margin. Never go higher than 70% max plate dissipation unless you like changing tubes often. My BDRI is biased at slightly over 50% and my 5F6A clone right at 70%. Both sound fantastic.

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Post subject: Re: Vintage Reissue '65 Deluxe Reverb mods?
Posted: Sat Jul 21, 2012 9:17 am
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22.7*430?

That can't be right.

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Post subject: Re: Vintage Reissue '65 Deluxe Reverb mods?
Posted: Sat Jul 21, 2012 12:10 pm
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Hou-Tex wrote:
22.7*430?

That can't be right.


I (amps) x V (volts) = P (watts)

0.0227 amp x 430 VDC = 9.761W

If your tube is a 14 watt tube, that 70%

If your tube is a 12 watt tube, well, I hope you have a spare handy (81%). :lol:

Are you sure about that plate voltage? According to the schematic, B+ is only 396 VDC.

http://support.fender.com/schematics/gu ... ematic.pdf

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Last edited by bluesky636 on Sat Jul 21, 2012 7:41 pm, edited 3 times in total.

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Post subject: Re: Vintage Reissue '65 Deluxe Reverb mods?
Posted: Sat Jul 21, 2012 12:18 pm
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Thanks Bill, mine are 14 watt, and I'm hot. lol

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Post subject: Re: Vintage Reissue '65 Deluxe Reverb mods?
Posted: Sat Jul 21, 2012 12:22 pm
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Hou-Tex wrote:
Thanks Bill, mine are 14 watt, and I'm hot. lol


I don't believe your plate voltage either. See my edited post above.

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Post subject: Re: Vintage Reissue '65 Deluxe Reverb mods?
Posted: Sat Jul 21, 2012 2:50 pm
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bluesky636 wrote:
Hou-Tex wrote:
Thanks Bill, mine are 14 watt, and I'm hot. lol


I don't believe your plate voltage either. See my edited post above.


I don't know what I'm looking at.

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Post subject: Re: Vintage Reissue '65 Deluxe Reverb mods?
Posted: Sat Jul 21, 2012 5:41 pm
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Hou-Tex wrote:
bluesky636 wrote:
Hou-Tex wrote:
Thanks Bill, mine are 14 watt, and I'm hot. lol


I don't believe your plate voltage either. See my edited post above.


I don't know what I'm looking at.


You're looking at a schematic diagram that shows the B+ (the voltage that provides power to the output tubes) is only 396 VDC. It is connected to the center tap on the tube side of the output transformer. It will drop a few volts by the time it gets to the output tube plates. In fact, the schematic shows the plate voltage as 391 VDC. So if the schematic is correct and B+ is only 396 VDC and you are measuring 430 VDC at the plates, you've got something flaky going on. 430 VDC for a B+ is something you would see for a 6L6GC powered amp, not a 6V6 powered amp. Of course, the schematic could be wrong, but I don't think so.

How did you measure the plate voltage? What is the AC line voltage coming out of your wall sockets? You should learn to read a schematic. Its not that hard.

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Post subject: Re: Vintage Reissue '65 Deluxe Reverb mods?
Posted: Sat Jul 21, 2012 6:42 pm
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Maybe my DVM needs to be calibrated.

Thanks anyway man.

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Post subject: Re: Vintage Reissue '65 Deluxe Reverb mods?
Posted: Sat Jul 21, 2012 6:51 pm
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Hou-Tex wrote:
Maybe my DVM need to be calibrated.

Thanks anyway man.


I doubt it. I have never seen a DVM that far off unless it had been damaged. There really is no user calibration on a DVM like on the old vacuum tube voltmeters. I think you need to figure this out before you do some damage. Even Stinger 22's plate voltage is a little high but at least closer to the schematic. Yours is off the grid in my opinion.

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Post subject: Re: Vintage Reissue '65 Deluxe Reverb mods?
Posted: Sat Jul 21, 2012 7:21 pm
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bluesky636 wrote:
Hou-Tex wrote:
Maybe my DVM need to be calibrated.

Thanks anyway man.


I doubt it. I have never seen a DVM that far off unless it had been damaged. There really is no user calibration on a DVM like on the old vacuum tube voltmeters. I think you need to figure this out before you do some damage. Even Stinger 22's plate voltage is a little high but at least closer to the schematic. Yours is off the grid in my opinion.


Metrology is part of my job and yes, DVM's can be calibrated.

No disrespect, and thanks for your help, but I was just looking for a simple formula.

BTW, tyronnes tubes ran the same as mine.

viewtopic.php?f=13&t=58087

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