Got my new amp

[cyto]

I decided on the Yaqin MS-20L, thanks to everyone here for all the info, it really did help. I would have preferred to build one but I just don't have the time.

I have been listening to this for 3 days now, about 4-5 hours total. Here are my "non audiophile" impressions:
1) I love the sound
2) I find myself flipping from triode to UL mode but listening mostly to triode
3) I have the preamp outs from the Technics hooked up so I can listen to the tuner, the Denon CD player is hooked directy to the amp. The tuner never sounded better, I tried the CD player going through the Technics first but lost something.
4) I seem to have quite a bit more headroom now than my Technics alone (both are 50wpc).

I have been told that it will sound better after the tubes burn in at about 100 hours. Now I was a TV repairman in the 70's when TV's had tubes (I passed the associate CET and State exams in 1976) and I do not remember tubes having a "break in" period. Is this break in for real or just peoples ears adjusting to the sound?

Anyway, thanks guys, I be jammin now :-)

[JoeE SP9]

Yes, tubes, especially power tubes do break in. Check the bias periodically and you'll see it probably needs adjustment several times during that first hundred hours. Me, I check the bias on my tubed mono blocks once a week minimum.

Unfortunately tubes also slowly degrade.

[E-Stat]

I do not remember tubes having a "break in" period. Is this break in for real or just peoples ears adjusting to the sound?

What typically requires more break in time is the film based coupling capacitors which were not commonplace forty years ago. Teflon caps are both the best sounding and the worst when it comes to break in time. Don't sweat it. Just enjoy playing lots of music!

rw

[Poultrygeist]

Nice push pull amp.

If it's a new unit from China you should roll those stock tubes ASAP. The difference will be night and day.

Over the years I've bought 4 tube amps including one Yaqin from Chinese ebay merchants and they all came with lousy tubes. The only Chinese tube I haven't rolled is the Shuguang 2a3c.

[cyto]

Nice push pull amp.

If it's a new unit from China you should roll those stock tubes ASAP. The difference will be night and day.

Over the years I've bought 4 tube amps including one Yaqin from Chinese ebay merchants and they all came with lousy tubes. The only Chinese tube I haven't rolled is the Shuguang 2a3c.

What replacements would you recommend for the 6J1 and EL34B?

I see a lot of people going with Gold Lion KT77 for the outputs, not sure about the 6J1's.

[Poultrygeist]

The very best 6J1 replacements are Western Electric 403B's. I also like the much cheaper Valve Electronic CV4010 which are said to be made by Mullard for military use.

As for the EL34B's I recommend Tung Sol's. JJ's are also far better than the stock Chinese tubes.

[cyto]

After about 35 hours of use I replaced the stock Shuguang 6J1's with Russian 6J1P-EV (Ebay from a guy in the Ukraine, Svetlana NOS 1982). The difference was noticeable and immediate. My wife even noticed it and told me to get more of the tubes for back up.

Next I will swap the outputs, probably after 100 hours.

[Feanor]

After about 35 hours of use I replaced the stock Shuguang 6J1's with Russian 6J1P-EV (Ebay from a guy in the Ukraine, Svetlana NOS 1982). The difference was noticeable and immediate. My wife even noticed it and told me to get more of the tubes for back up.

Next I will swap the outputs, probably after 100 hours.

Bear in mind that tubes are a component that definitely do need a few hours of burn-in.

[Jack in Wilmington]

Hey cyto, did you replace those output tubes yet? I'm using 6550Eh from Electro Harmonix and I was thinking of rolling something else and was wondering how you made out.

[cyto]

Hey cyto, did you replace those output tubes yet? I'm using 6550Eh from Electro Harmonix and I was thinking of rolling something else and was wondering how you made out.

Not yet, looks like I have to wait for Santa on this. I'm thinking he will bring Genalex Gold Lion KT77's.