Ron’s New System

[DasguteOhr]

For me the best coppercable i know sommercable epilogue sym 35pf/m.
Unfortunately, it's no longer cheap, the word has gotten around about the quality

Sommer Cable Epilogue Micro Cable 3,0

Sommer Cable Epilogue 3,0: die Referenz im Bereich NF-/Audiokabel; ideal für Verbindungen mit höchsten Ansprüchen (Vor-/Endstufe, CD-Player, DVD, DAT, ...) vor allem im Studio- und Hifi-Bereich; sehr neutrales, verfärbungsfreies und räumliches...

www.thomann.de

 

[Ron Resnick]

Ron, I have a set of those Black Treasure 6CA7 from about 10 years ago (who knows if the current ones are the same) and they are very good, I actually prefer them in my amp to Mullard xf2, and they have been totally reliable (again who knows if the new ones are the same). The Mullards are just too warm. KT77 is another interesting option. I haven’t tried the Russian Gold Lions, but the JJ KT77 is a good sounding tube but brighter (and more resolving IMO) than EL34 (except for maybe the 10 year old Black Treasures)
Since the Jadis can take bigger KT tubes and EL34, can it do KT66? Now that in my opinion is the best of all these tube types, with great resolution, dynamics and the best treble. Tight accurate bass, not the warmth and bloat of EL34 or KT88. More like a higher resolution KT90, but half the power. The Russian “Gold Lions” are good, but GEC KT66 (either grey glass or clear) are fantastic tubes. Still decent supply of good testing tubes around since they seem to last forever.

Thank you for this report!

How would your recommendation change if I told you that I don't care about "tight accurate bass" because in my application the tubes are not tasked with reproducing bass frequencies?

 

[Ron Resnick]

For me the best coppercable i know sommercable epilogue sym 35pf/m.
Unfortunately, it's no longer cheap, the word has gotten around about the quality

Sommer Cable Epilogue Micro Cable 3,0

Sommer Cable Epilogue 3,0: die Referenz im Bereich NF-/Audiokabel; ideal für Verbindungen mit höchsten Ansprüchen (Vor-/Endstufe, CD-Player, DVD, DAT, ...) vor allem im Studio- und Hifi-Bereich; sehr neutrales, verfärbungsfreies und räumliches...

www.thomann.de

Thank you for this recommendation!

"Best" in what sonic ways? With which associated components?

What is the longest interconnect run of this cable you have used?

 

[Mendel]

Thank you for this report!

How would your recommendation change if I told you that I don't care about "tight accurate bass" because in my application the tubes are not tasked with reproducing bass frequencies?

I would say that KT66 has the best high end reproduction of the tubes discussed (In my amp and in my opinion). Also very holographic imaging, although the midrange is not as warm as EL34 or even KT88, but perhaps more accurate (linear).
If you decide to go with EI KT90, be aware that there are several different types, and the latter ones produced during and after the war can often be unreliable and prone to failure. I fear many of the ones on eBay are these later types. There used to be a report on the internet (on the Manley web site) from EveAnna Manley describing the 4 types of EI KT90 but it appears to have disappeared. I have no experience with the latter types, but can provide pictures of the first two types.
The first are rare, they all (I believe) have the Manley red label as they were made exclusively for them. The second version can be found with the blue Manley label, or white EI markings. These ones have many weld markings on the plates which makes it easy to differentiate them from the later tubes.
In the photos below, type 1 tube on the left, two type 2 tubes on the right.

 

[Ron Resnick]

Thank you very much! Are you able to tell which KT90s these are in this advertisement?

KT90 EI Yugoslavia Platinum Matched Quad dual OO getter NOS NIB 100% 1993 Codes | eBay

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[Argonaut]

I would say that KT66 has the best high end reproduction of the tubes discussed (In my amp and in my opinion). Also very holographic imaging, although the midrange is not as warm as EL34 or even KT88, but perhaps more accurate (linear).
If you decide to go with EI KT90, be aware that there are several different types, and the latter ones produced during and after the war can often be unreliable and prone to failure. I fear many of the ones on eBay are these later types. There used to be a report on the internet (on the Manley web site) from EveAnna Manley describing the 4 types of EI KT90 but it appears to have disappeared. I have no experience with the latter types, but can provide pictures of the first two types.
The first are rare, they all (I believe) have the Manley red label as they were made exclusively for them. The second version can be found with the blue Manley label, or white EI markings. These ones have many weld markings on the plates which makes it easy to differentiate them from the later tubes.
In the photos below, type 1 tube on the left, two type 2 tubes on the right.

Great post @Mendel … If in doubt stick to dual getter ring and multiple weld points ( the latter beings among revisions requested by Manley after the first production runs )

 

[Argonaut]

Viz : Re branded “Gold Aero” Type II



Factory Type II

 

[DasguteOhr]

Viz : Re branded “Gold Aero” Type II

View attachment 116621

Factory Type II

View attachment 116622
View attachment 116623

Before the company was renamed in Ei Yugoslavia was called "Radio Roentgen" these tubes rarely appear anymore. In the past, no one wanted communist-made tubes in the West. In ten years, all people say what a good tube look "the forgotten Philips from the East"

 

[DasguteOhr]

For me the best coppercable i know sommercable epilogue sym 35pf/m.
Unfortunately, it's no longer cheap, the word has gotten around about the quality

Sommer Cable Epilogue Micro Cable 3,0

Sommer Cable Epilogue 3,0: die Referenz im Bereich NF-/Audiokabel; ideal für Verbindungen mit höchsten Ansprüchen (Vor-/Endstufe, CD-Player, DVD, DAT, ...) vor allem im Studio- und Hifi-Bereich; sehr neutrales, verfärbungsfreies und räumliches...

www.thomann.de

It is neutral, high resolution, it brings every change in the chain to light. That makes it a very good cable for me.
Length 8.5 m with active speakers and power amps no problems with sound quality

 

[Mendel]

Thank you very much! Are you able to tell which KT90s these are in this advertisement?

KT90 EI Yugoslavia Platinum Matched Quad dual OO getter NOS NIB 100% 1993 Codes | eBay

Find many great new & used options and get the best deals for KT90 EI Yugoslavia Platinum Matched Quad dual OO getter NOS NIB 100% 1993 Codes at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Ron they are not type 2 (no weld marks) and doubtful they are type 1 without the VTL label so probably type 3. Type 3 produced before the war were pretty reliable (I believe Jim Mcshane sold many of them in the late 1990s and early 2000s), afterwards not so much. Hard to tell the vintage of the ones in your photo so if you go with them you better get 12 or even 16 for the inevitable failures (at $1300 a quad Ouch!) .I agree with Argonaut that you should try to find the welded type 2 if possible.
For more info, I found a thread on Audiokarma you might want to check out entitled EI KT90 type 2 which has photos of the four different types from the lost EveAnna Manley report.

 

[microstrip]

Somewhat one of the Achilles heals where multi output valve topologies are concerned, especially when attempting to match increasingly hard to source and ever more expensive NOS valves .

In fact, most amplifiers using many tubes in parallel allow individual bias. Buy in fact, mathced tubes is an ambiguous term - tubes can be matched for plate current or transconductance. Often sellers just address the plate current.

If we have the complete information or a tube tester and knowledge things become easier - for example we can match both phases of the push pull sorting tubes for equal sum of individual transconductance in each phase.

Plate current is very important in push pull amplifiers because current imbalance in the output transformer will saturate the core, causing distortion even at low power and strongly limiting the available power.

Poorly matched total transconductance of each phase creates distortion. I remember that the old Audio Research D70 amplifier had a trimmer in the driver stage that could be adjusted with a distortion meter for minimal distortion when we changed tubes - it was a two minute affair.

 

[microstrip]

It is neutral, high resolution, it brings every change in the chain to light. That makes it a very good cable for me.
Length 8.5 m with active speakers and power amps no problems with sound quality

Can we get it unterminated at custom longer length?

 

[Argonaut]

Before the company was renamed in Ei Yugoslavia was called "Radio Roentgen"

Now we are talking Tovarish

 

[microstrip]

Thank you very much! Are you able to tell which KT90s these are in this advertisement?

KT90 EI Yugoslavia Platinum Matched Quad dual OO getter NOS NIB 100% 1993 Codes | eBay

Find many great new & used options and get the best deals for KT90 EI Yugoslavia Platinum Matched Quad dual OO getter NOS NIB 100% 1993 Codes at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Ron,

You probably know about it, but we should not put tubes that have not be tested in another amplifier in the Siegfried. The safety system of the amplifier that switches poor tubes to protect the amplifier off is meant to detect tubes that degrade after normal use - it will not save your amplifier for tubes with unexpected shorts or other violent problems.
For this purpose and burn-in I use my trusted and robust, microprocessor free, conrad johnson LP275m, that is fuse protected - in worst case I have just to replace the 20 ohm cathode resistor. As I am a prudent man, for these phases I use a quick fuse of much lower raring, not the expensive KTKs!

Remember that good tube equipment is intrinsically reliable but 90% of breakdowns happen when are carrying experiments!

 

[Ron Resnick]

It is neutral, high resolution, it brings every change in the chain to light. That makes it a very good cable for me.
Length 8.5 m with active speakers and power amps no problems with sound quality

Thank you.

 

[DasguteOhr]

Can we get it unterminated at custom longer length?

only from sommercable directly. Unfortunately, it was once available by the meter and was no longer available for sale. you need proof of dealer

Only albedo by meter

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Or carbocab solidcore cable really good

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[Mendel]

microstrip makes a great point about being able to individually bias each tube which allows you to use (NOS) tubes that may not be perfectly matched. Definitely a feature to look for in a push pull tube amp. Not sure, but wouldn’t the auto-bias in the Jadis accomplish roughly the same thing?

 

[DasguteOhr]

In fact, most amplifiers using many tubes in parallel allow individual bias. Buy in fact, mathced tubes is an ambiguous term - tubes can be matched for plate current or transconductance. Often sellers just address the plate current.

If we have the complete information or a tube tester and knowledge things become easier - for example we can match both phases of the push pull sorting tubes for equal sum of individual transconductance in each phase.

Plate current is very important in push pull amplifiers because current imbalance in the output transformer will saturate the core, causing distortion even at low power and strongly limiting the available power.

Poorly matched total transconductance of each phase creates distortion. I remember that the old Audio Research D70 amplifier had a trimmer in the driver stage that could be adjusted with a distortion meter for minimal distortion when we changed tubes - it was a two minute affair.

If you want it to be perfect, the only way to do it is with a spectrum analyzer. For a pushpull amplifier, k3 thd dominates. For example, you control 3kz fundamental wave like this video, you can see k3 9khz there. if the bias is asymmetrical k2 will increase. You have symmetry when k2 is completely off the screen. But this is possible with amplifiers that have an adjustable negative grid bias with a balance pot. so not for jadis.

 

[microstrip]

microstrip makes a great point about being able to individually bias each tube which allows you to use (NOS) tubes that may not be perfectly matched. Definitely a feature to look for in a push pull tube amp. Not sure, but wouldn’t the auto-bias in the Jadis accomplish roughly the same thing?

No. Although auto-bias using a cathode resistor self adjusts the tube current it still depends on the tube parameters. One of the reasons why some people consider that Jadis amplifiers are not reliable is because they are often used with non adequate tubes. Amplifiers needing matched tubes should use tubes matched after burn-in. See https://www.whatsbestforum.com/threads/a-visit-to-jadis.10696/post-194357

 

[microstrip]

If you want it to be perfect, the only way to do it is with a spectrum analyzer. For a pushpull amplifier, k3 thd dominates. For example, you control 3kz fundamental wave like this video, you can see k3 9khz there. if the bias is asymmetrical k2 will increase. You have symmetry when k2 is completely off the screen. But this is possible with amplifiers that have an adjustable negative grid bias with a balance pot. so not for jadis.

Yes, and anyone can have it for free! But many audiophiles would not have a good night sleep if they looked at the distortion spectrum of their tube amplifiers!