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Gold Lion KT77 tubes for Primaluna Amp - a few questions

I have a Primaluna Dialog Premium HP amp (stereo mode), and am currently running the stock el34s.  With 4 per channel, the re-tubing and tube rolling discussions can get expensive, so I have been treading lightly. Having read numerous threads (lots of great discussions and comments - thanks to everyone who has contributed) I have decided to give the golden lion KT77 tubes a go.  I have a few questions.

1- in looking around, I see there a multiple sources of the tubes.  From multiple eBay sources (some which appear to specialize in tubes and others that do not, some are “genelex authorized dealers”) to the well known Upscale Audio.  The pictures of the tubes all appear to be similar.  Am I correct in assuming they are all the same genelex “made in Russia” tubes?

2- one of the things that appears to differentiate the different suppliers is how they match them.  Is all matching the same, as long as they are “close enough”?  I see factory matched, hand matched, transconductance, plate current, 5%, 10%.  Lots of stuff here.  ESPECIALLY for the self biasing Primaluna amp, how critical is the matching method?

3- one last question about dealers.  I am in the Chicagoland area and I recall somewhere someone saying or posting that they buy all their tubes from a local company, that was very good and knowledgeable. Does anyone know who this dealer is? All things being equal, supporting the local economy (and being able to talk to another audiophile across the counter) is a good thing.

finally, just so we don’t go down a different rabbit hole, I did replace the center two 12au7s with mullard NOS 4003 from Upscale Audio.  One of the best things I have done to my system. Wow.  I plan on changing the other four, too.

THANKS 

Bill
meiatflask
davide256's avatar
davide256
399 posts
 
I run a Prologue Premium integrated. I used to use Mullard CV4003 pre tubes but found as I dabbled with about a dozen others that they rolled off the high frequencies and added some bass distortion. Preferred pre tubes nowBugle Boy 12AU7s in front socketsTelefunken 12AU7s in back sockets
In the power tube sockets, I've used Tungsol EL34, new Mullard EL34, Golden Lion KT88's, Tungsol KT-120/150's
Tungsol KT 150's were the best blend of tonal accuracy, speed,  and low bass authority.  KT88's were my least favorite, something weird, artificialsounding about tone color.

meiatflask OP
155 posts
 
Johnss- tell me more about the coupling caps. Are there any references, or instructions/pictures/youtubes available and where do buy the caps from? I assume this is not rocket science and is easily done by anyone who is good with a soldering iron.

also, what do you think of the KT77?
johnss
577 posts
 
If you can solder, its pretty easy to replace the coupling caps. All point to point wiring on the PL amps and pre amps. The SCRs that come from the factory are ok. They are very reliable, which is why so many use them, but the copper foil caps are much more organic sounding.

There are several sources on the web, soniccraft.com partsconnexion.com that carry them. the Jensen copper foils have an aluminum outer case, the Jupiter copper foils have an outer cardboard or paper case coated in wax.

The PL gear has plenty of  ventilation, so have not had a problem with either.

I would send a few before and after pics, but don't think there is an option here to post photos. The cap change out is big improvement over stock, If you like the sound of VAC amps, the caps will get you much closer.

J
jbhiller's avatar
jbhiller
1,437 posts
 
johnss, any chance if folks PM you with their email you could send pics of your unit showing the actual caps you swapped?
johnss
577 posts
 
Sure, not a problem.

Also have a PL prologue 4 I have gone through with copper caps.

Am pretty sure I have before and after pics. Not too difficult of a job. If you lived nearby would say just bring yr amp over and can walk you through the steps.
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