Reduction

[M42]

Hi All,

I recently completed my Reduction which now has about 90 hours on it.  A hissing noise has developed in the right channel during the last few hours of operation, a very faint hum can be heard below that. This does not seem to adversely affect the sound when the turntable is operating. I removed the turntable interconnects, the noise was still present, I disconnected my Crack amp...it remained essentially silent. I swapped the tubes on the Reduction and the noise followed the tube. From what I have read here on the forum, the tube may simply need more time to burn in, or be replaced?

Jeff

[earwaxxer]

Hey Jeff - IMO if the problem follows the tube then that tube gets set "aside". I know thats a hard thing to do with an expensive tube. Sometimes you just got to put her down...

[M42]

Hi Eric,

Thanks for your reply...I'll look for a pair of suitable replacements.

Jeff

[2wo]

If the noise is not too objectionable, let it cook for a while.

In the mean time, go shop for a tube or two. Don't spend a lot, just try something new...John 

[Grainger49]

Jeff,

Look here:

http://www.bottlehead.com/smf/index.php/topic,1029.msg7557.html#msg7557

My favorite tube is the second one in the list.  They are USSR Military surplus tubes and you can get them really cheaply.  I go with the EV since they are maybe a dollar or two more than the standard tube.

[M42]

Gentlemen,

Thank you all for the advice...Grainger, I've found a source for a matched pair of Russian  tubes -
Reflector 6N23P-EV Military Cryo. In your opinion, is the cryo tube worth the up charge?

Thanks again,

Jeff

[Grainger49]

Jeff,

I don't know.  I have never bought a cryo treated tube.  PM the source, I will get a pair and do a little testing.

Thanks....

[Grainger49]

Jeff,

I got the tube today.  I listened to a side of Russ Barrenberg's Moving Pictures and keyed on one song.  Then popped in the Cryo treated tube. 

It might have been louder.  But that is odd.  I did hear better image specificity.  I could hear where each instrument was easier.  I keyed in on Jerry Douglas not Russ Barrenberg.  I think I heard better tonal balance.  And on the last cut on the first side I heard more wood from the violin (Mark O'Conner).

For now I will leave in the Cryo treated tube and swap back later. 

I can't say now that it is worth 3+ times the cost of the tube but I might later. 

[earwaxxer]

Yep, there you go... Tubes are a bitch.... They are definitely of the female persuasion.... In a good way! Love em...

[M42]

Hi Grainger,

Thanks very much for your input. I'll run my present tubes a while longer to see if they settle down. I will spring for a matched pair of these cryo tubes and report on the results. My first adventure with tube rolling...should be fun!

Jeff

[Mmaxed]

With 30-35 hours on my Reduction, I definitely have one tube that is louder or stronger than the other.  Swapping tubes side to side, and switching back to my other pre has proved it.  Is this part of break in or should I order up some new tubes?

[camaroguy]

Hi guysand gals, new guy here. I had the same problem with the supplied tubes for the reduction. One tube had more output and less noise then the other. I didn't give them much time to even out though because a friend gave me a pair of Amperex USN-CEP 7308 goldpins. All I can say is wow, even output, musical and dead quiet. I'm going to order the upgrade kit today, can't wait to here the Reduction after the upgrade. Hope this helps, camaroguy.

[Mmaxed]

Hmmm..nearly doubling the price of the rig with a tube roll??  Don't know why it seems wrong, when I would have done the same thing modding a snowmobile 10 years ago.  And the sled cost 7k.

[camaroguy]

The tubes I mentioned were given to me along with a set of Mullads that sound good also. The point I was making was, I would try a different set of tubes. I wouldn't buy these tubes either with what people are asking for them, I just happen to have a really nice friend. Hope this helps, camaroguy.

[Mmaxed]

I was kidding about the tubes.  Like I said, I would have done the same type of thing with something much more expensive.  Not sure why it seems like over kill here.

I did order some new tubes, will report back when they have ran for a while.