[gibosi]

I assume that it is only these new 6ZH1P-EV gold pin tubes that are problematic. That is, your other tubes sound fine. If so, then the problem would seem to be with these particular tubes.
 
First, if these tubes actually have gold pins, I find that to be suspicious. In my experience, 6ZH1P-EV have rhodium pins, so I wonder if the gold plating might have been done by a third party....  Ordinarily, given the symptoms you describe, I would suggest scraping and cleaning the pins to ensure that there is a good connection in the socket. But if they are gold plated, that really shouldn't be necessary. Otherwise, the best I can suggest is to allow them to burn in for 20 or so hours and see if they quiet down.
 
Good luck!

 

[MunkyOne]

  I assume that it is only these new 6ZH1P-EV gold pin tubes that are problematic. That is, your other tubes sound fine. If so, then the problem would seem to be with these particular tubes.
 
First, if these tubes actually have gold pins, I find that to be suspicious. In my experience, 6ZH1P-EV have rhodium pins, so I wonder if the gold plating might have been done by a third party....  Ordinarily, given the symptoms you describe, I would suggest scraping and cleaning the pins to ensure that there is a good connection in the socket. But if they are gold plated, that really shouldn't be necessary. Otherwise, the best I can suggest is to allow them to burn in for 20 or so hours and see if they quiet down.
 
Good luck!

Thanks Gibosi,
 
The pins are indeed gold coloured, if not gold plated.  I cleaned the pins with a de-oxidising fluid before installing.  I will give them a slightly more abrasive clean before installing again.  As you sugges I will let these tubes run for 20+ hours and see if anything changes. 
 
The boxes are marked correctly, in Russian, and the tubes have the correct markings (Rocket logo, the OTK military designation).   However, as you know, all kinds of things happen in the tube market.  So, I may look around for another pair, from another vendor to compare them.
 
Either way, the microphonics and other noises are beyond acceptable.  If the burn-in period doesn't yeild any improvement, I will contact the eBay vendor.
 
Aside from the noise, they play very well indeed in my setup.
 
Many thanks for your suggestions

 

[gibosi]

I purchased a couple pairs of these back in 2012, from this vendor, and they were fine.
 
http://www.ebay.com/itm/2-pc-6J1P-EV-EF95-6F32-6AK7-Gold-Platinum-grid-NIB-/130436695928?

 

[MunkyOne]

  I purchased a couple pairs of these back in 2012, from this vendor, and they were fine.
 
http://www.ebay.com/itm/2-pc-6J1P-EV-EF95-6F32-6AK7-Gold-Platinum-grid-NIB-/130436695928?

Thanks again gibosi.  Maybe I will order another pair of tubes.  Would you believe it!  This is the same vendor I ordered mine from!  I will contact him and see if he has any non-gold pin in stock.       I am currently burning the voskhods in, and will report back with any changes observed.
 
Regards.

 

[WilliamLeonhart]

What is the better version: the 6cq6 or the 408a (both provided by LD)? Before spending money on other tubes I just dont want to end up with stock tubes that are absolutely useless. I suppose these two options are both good but different and I don't know which one is better for my taste.

 

[gibosi]

"Better" is in the ears of the listener. These tubes are different and what is better for me, or others who reply, may not be better for you. Going by cost alone, I believe that the 6CQ6/EF92 is the better deal for $20, as you can find 408A's on eBay for less than $52.
 
Further, if you search for 6HM5 in this forum, many believe this is better than either the EF92 or the 408A, and it is usually cheaper, as well.
 
Have fun!

 

[WilliamLeonhart]

Thank you for your input, Gibosi. Actually I was pondering over the stock versions of I+, which include the 6CQ6 and the 408A. I remember reading about the 6CQ6 in a detailed tube guide on head-fi, but not much information was available on the 408A.

 

[forestitalia]

Yesterday decided to try the 408A type I had in the drawer since June: this is a very significant improvement to me!
Bass and midbass very good, all music much controlled and precise but still valve sound.
 

 

[gibosi]

Since you like the Western Electrics, then you might like Sylvania. To my ears, this was the best 408A. 
 

 
But still, I think the 6HM5 is better. And a lot cheaper!
 

 

[forestitalia]

Hi Gibosi! Wich Opa you use with the 6HM5? And what brand are in the pictures?
 
Would be that: http://www.ebay.co.uk/itm/1x-6HA5-6HM5-EC900-SYLVANIA-NOS-Tube-Rohre-Valvola-Lampe-TSF-Valvula-/260999544888?pt=Vintage_Electronics_R2&hash=item3cc4c90038

 

[gibosi]

  Hi Gibosi! With wich Opa you use the 6HM5? And what brand are in the pictures?
 
Would be that: http://www.ebay.co.uk/itm/1x-6HA5-6HM5-EC900-SYLVANIA-NOS-Tube-Rohre-Valvola-Lampe-TSF-Valvula-/260999544888?pt=Vintage_Electronics_R2&hash=item3cc4c90038

 
I am using the MUSES02. To my ears, the best of all I tried.
 
There appear to be three good versions of the 6HM5: The Sylvanias you found, The EIs from Yugoslavia and the GE's. The ones I posted are Mullards. GE procured them from Mullard and put their own label on them. As far as I know, GE didn't make this tube, so all of them are rebrands. The only caveat is always buy the tall bottles. In my opinion, the short bottles are quite poor.

 

[forestitalia]

   
I am using the MUSES02. To my ears, the best of all I tried.
 
There appear to be three good versions of the 6HM5: The Sylvanias you found, The EIs from Yugoslavia and the GE's. The ones I posted are Mullards. GE procured them from Mullard and put their own label on them. As far as I know, GE didn't make this tube, so all of them are rebrands. The only caveat is always buy the tall bottles. In my opinion, the short bottles are quite poor.

Thanks Gibo for your explanation. With the 408A the Little Dot is already at a very good level, but if you say that the 6HM5 are better I will take the Silvania. The  Ei I don't know, are the Yugo like this: http://www.ebay.it/itm/6HM5-EC900-Lot-of-four-4-tubes-EI-Yugoslavia-NOS-free-shipping-/251611916081?pt=Vintage_Electronics_R2&hash=item3a953d2731  ?

 

[gibosi]

  Thanks Gibo for your explanation. Perhaps I will take the Silvania, Ei I don't know are the Yugo like this: http://www.ebay.it/itm/6HM5-6HA5-EC900-export-quality-audio-triode-tube-NOS-FREE-SHIPPING-/300879467071?pt=Vintage_Electronics_R2&hash=item460dd0523f  ?

 
Yes, that is the EI manufactured in Yugoslavia. And notice "Proposta d'acquisto":: I know several people who got them for US $5 each.

 

[forestitalia]

   
Yes, that is the EI manufactured in Yugoslavia. And notice "Proposta d'acquisto":: I know several people who got them for US $5 each.

Tried, they refused so I prefer take Sylvania from Italy. May ask you where did you take the Muse02? Are not easy to find.

 

[gibosi]

  Tried, they refused so I prefer take Sylvania from Italy. May ask you where did you take the Muse02? Are not easy to find.

 
http://www.ebay.com/itm/400418607953?
 
I ordered both the MUSES01 and the MUSES02 from this vendor, but preferred the 02.