Reduction weak sound on r side.

patm · 4032

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Offline patm

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on: May 17, 2015, 09:23:25 AM
Hi all,
Finished up the reduction about a week ago. R & V checks looked good (didn't pay enough attention), I must say that this is my first analog source so the sound blew me away right from the start. After listening for a week I noticed a lack of dynamic information from the right channel. I needed two extra clicks on the volume to even come close to the L channel. Took the reduction back to the bench and went through the assembly steps again and found no problems. (I was looking for a misplaced resister). The resisters were all correct. Here are the voltage readings that I found were off.

7- 70 to 90.  119
13- 70 to 90. 117.8
14- 70 to 90. 118
15- 70 to 90. 118.8

Help
Pat McSween

In the beginning there was nothing, then it blew up!

FP III, Paramount 300b (Takatsuki TA-300B), both with Mundorf S/O caps, Mikes iron, HFBG Eros,Oppo 103,Rega RP6 2m black ,Vaughn Triode JR II


Offline Paul Birkeland

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Reply #1 on: May 17, 2015, 11:44:18 AM
Can you leave your Reduction on overnight, then recheck those voltages?

How are your voltages at 33 and 37?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline patm

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Reply #2 on: May 17, 2015, 12:14:42 PM
33- 6.2
37- 6.1

In the beginning there was nothing, then it blew up!

FP III, Paramount 300b (Takatsuki TA-300B), both with Mundorf S/O caps, Mikes iron, HFBG Eros,Oppo 103,Rega RP6 2m black ,Vaughn Triode JR II


Offline patm

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Reply #3 on: May 18, 2015, 03:33:45 AM
Left the Reduction on overnight and retested the 4 readings with the following results.

 7- 118.2
13- 117.1
14- 117.3
15- 118.1

33 & 37 remain unchanged @ 6.2 & 6.1

In the beginning there was nothing, then it blew up!

FP III, Paramount 300b (Takatsuki TA-300B), both with Mundorf S/O caps, Mikes iron, HFBG Eros,Oppo 103,Rega RP6 2m black ,Vaughn Triode JR II


Offline Paul Birkeland

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Reply #4 on: May 18, 2015, 05:49:31 AM
I would see if you could borrow a spare tube from a friend just to rule that out.  Generally, high plate voltages are indicative of low emission.  Often times these older Russian tubes need a couple days of constant running to wake up, then they will return to proper working order.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline patm

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Reply #5 on: May 18, 2015, 06:19:01 AM
I had a pair of Tungsram nos that I had got for this amp. The tubes appear to have been the problem.

 7- 74.3
13-73.0
14- 72.7
15- 73.0

In the beginning there was nothing, then it blew up!

FP III, Paramount 300b (Takatsuki TA-300B), both with Mundorf S/O caps, Mikes iron, HFBG Eros,Oppo 103,Rega RP6 2m black ,Vaughn Triode JR II


Offline Doc B.

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Reply #6 on: May 18, 2015, 06:42:32 AM
You might put those weak tubes in and just cook them for a week straight when you have the opportunity. Sometimes they need a fair amount cook time to get the cathodes emitting. If nothing else you will know by then whether they are going to improve or not.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline patm

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Reply #7 on: May 18, 2015, 10:34:19 AM
Man, you guys ROCK, thanks is not even close to equal the smile on my face as I spin album after album this afternoon. I was so enthralled at first even with a bum channel. Now this thing just keeps sounding better and better. Maybe I will listen for a week and then do the integration.

Doc that sounds like a good idea. Now to find time to burn them in. Right now it sounds to good.

Thanks for the help.
Pat McSween

In the beginning there was nothing, then it blew up!

FP III, Paramount 300b (Takatsuki TA-300B), both with Mundorf S/O caps, Mikes iron, HFBG Eros,Oppo 103,Rega RP6 2m black ,Vaughn Triode JR II