Bottlehead Forum

Bottlehead Kits => Legacy Kit Products => Reduction => Topic started by: patm on May 17, 2015, 09:23:25 AM

Title: Reduction weak sound on r side.
Post by: patm 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

Title: Re: Reduction weak sound on r side.
Post by: Paul Birkeland 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?

Title: Re: Reduction weak sound on r side.
Post by: patm on May 17, 2015, 12:14:42 PM

33- 6.2
37- 6.1

Title: Re: Reduction weak sound on r side.
Post by: patm 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

Title: Re: Reduction weak sound on r side.
Post by: Paul Birkeland 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

Title: Re: Reduction weak sound on r side.
Post by: patm 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

Title: Re: Reduction weak sound on r side.
Post by: Doc B. 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.

Title: Re: Reduction weak sound on r side.
Post by: patm 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