Ron’s New System

[DasguteOhr]

I was in mid composition when you beat me to it

Sorry..I can only repeat myself, I am not a fan of Jadi's older driver concepts ecc82 on ecc83 from a technical point of view to drive multiple power tubes. That's why I welcome the update of the 100. Unfortunately, there are no schematics on the internet to analyze it in detail. no bashing

 

[Ron Resnick]

I found a purported comparison of Cardas Clear Reflection interconnect versus Cardas Clear Beyond interconnect.

Cardas has the “Clear” line above this reflection line and they state that the Reflection is a mix of Golden Reference and the new Clear. This means warmth, body, and glow but with air and details this time ; ) The higher up the Cardas ladder “Clear” would bring even more of the “Clear” and less of the “Warmth” and “Clear Beyond” even more so. The Reflection line is about a balance of warmth and clear all in one cable.

I am going to try one or the other. I am tempted to "split the baby" and to try the Clear Reflection (single-ended).

Francisco, I know you used to have one of the Goldens. Did you ever try Clear Reflection?

 

[Folsom]

Have you tried the stereo with normal power cables of any kind?

Why not get some low capacitance IC's first so you can know and identify the difference in sound on that account. That'll give you a nice baseline to understand changes you want, with an actual figure that can help get you started.

 

[Ron Resnick]

Have you tried the stereo with normal power cables of any kind?

Yes, the Iconoclast power cables are basically Belden.

 

[Ron Resnick]

Why not get some low capacitance IC's first so you can know and identify the difference in sound on that account.

The new Gotham is lower in capacitance than the Belden 1192A.

 

[Argonaut]

I just read it. Thank you!

I don't know how the slightly different electrical characteristics of the EL84 versus the EL86 affect the JA100s. So I don't have too many variables up in the air at the same time, I am going to stay with EL86s for now.

I have NOS Mullard EL86s on their way to me.

I don’t really see the relevance in that particular review other than general observations regarding build quality etc , the EL84 is not being utilised in the Jadis circuit in the signal output stage directly coupled with the output transformers ! Rather as an additional gain stage ? , how various brands sound as output valves being of lesser import one would think . Ergo a vary fine sounding early 60’s double getter Blackburn Mullard might not perform as well in the JA100 as say a Sovtek EL84M , the Mullard being totally wasted in that role.

 

[bonzo75]

I don’t really see the relevance in that particular review other than general observations regarding build quality etc , the EL84 is not being utilised in the Jadis circuit in the signal output stage directly coupled with the output transformers ! Rather as an additional gain stage, how various brands sound as output valves being of lesser import one would think . Ergo a vary fine sounding early 60’s double getter Blackburn Mullard might not perform as well in the JA100 as say a Sovtek EL84M .

You can only use it to shortlist, you will never get an exact match without trying, but that is pretty consistent with other El84 feedback if the Soviet one is good he should try both, if he chooses to try the EL84.

 

[Ron Resnick]

I don’t really see the relevance in that particular review other than general observations regarding build quality etc , the EL84 is not being utilised in the Jadis circuit in the signal output stage directly coupled with the output transformers ! Rather as an additional gain stage ? , how various brands sound as output valves being of lesser import one would think . Ergo a vary fine sounding early 60’s double getter Blackburn Mullard might not perform as well in the JA100 as say a Sovtek EL84M .

I agree that it's difficult to predict any sonic results in advance of actual listening.

 

[Folsom]

The new Gotham is lower in capacitance than the Belden 1192A.

It's still not low.

Yes, the Iconoclast power cables are basically Belden.

Your signature has both. For the cost of the Iconoclast I can't say I'd expect them to be anything like stock cables (of which Belden doesn't do, they have some shielded bulk wire).

 

[Ron Resnick]

It's still not low.



Your signature has both. For the cost of the Iconoclast I can't say I'd expect them to be anything like stock cables (of which Belden doesn't do, they have some shielded bulk wire).

I appreciate you thinking about my system!

What is your concern about the power cables?

Questions about capacitance were raised by others on the thread here, not by me. I have no concern that interconnect capacitance is causing any sonic problems. If anything I have no objection to a little HF roll-off. I have no actionable concern regarding capacitance.

 

[Argonaut]

You can only use it to shortlist, you will never get an exact match without trying, but that is pretty consistent with other El84 feedback if the Soviet one is good he should try both, if he chooses to try the EL84.

Various EL84 options mostly still available … however Rons incoming Mullard EL86’s might just hit it out of the park for him

 

[jadis]

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

View attachment 116654

In post # 3, Gary mentioned this:

"Every single tube that they receive (they do not manufacture their own tubes) are burned in for 120 hours before being measured and matched. They they are burned in again, to ensure that the do not drift. That is why Jadis amplifiers are not easy to bias - they should be biased when new tubes are put in, and then they should be left alone."

Does this mean that even for Class A auto-bias Jadis amps, there is a new to check bias when new tubes are put in?

How does the Class A auto bias function of Jadis work? Some tech told me that it is auto biased by installing matched pair tubes. Does it mean all you need are 4 matched pairs even if the 4 pairs are not balanced to each other (in an amp that uses 4 power tubes per channel, for example).

 

[dan31]

I found a purported comparison of Cardas Clear Reflection interconnect versus Cardas Clear Beyond interconnect.

Cardas has the “Clear” line above this reflection line and they state that the Reflection is a mix of Golden Reference and the new Clear. This means warmth, body, and glow but with air and details this time ; ) The higher up the Cardas ladder “Clear” would bring even more of the “Clear” and less of the “Warmth” and “Clear Beyond” even more so. The Reflection line is about a balance of warmth and clear all in one cable.

I am going to try one or the other. I am tempted to "split the baby" and to try the Clear Reflection (single-ended).

Francisco, I know you used to have one of the Goldens. Did you ever try Clear Reflection?

Ron have you tried any of the older Cardas?

Golden Cross in particular can be a wonderful cable as a single cable to tune a system. I have a set of Golden Cross XLR and Neutral Reference XLR. Both have their charms.

 

[Hi-FiGuy]

Last week I hunted down Tom, the highly respected technician from Brooks Berdan Ltd., whom most people in Southern California relied upon to repair Jadis amplifiers. Unfortunately Brooks Berdan Ltd. sold away its test bench and inventory of Jadis parts.

How is Tom doing, is he still in the business? He is an invaluable resource in the industry, going to be extremely difficult to find someone young to follow in his footsteps of knowledge and he is a character to boot.

 

[jadis]

Microstrip, Salectric,

Yes, it may be a relatively simple tube circuit, but you still must find an experienced and reliable technician you trust. Nobody in my area likes the George Meyer repair firm, to which I believe the Jadis distributor now refers people.

Absolutely. When I had the JA200s, I had to make sure that the local distributor had an in-house technician who does home service around the city. He did. So on a couple of times the power supply popped something, the tech man was sent to my house and he fixed and replaced the broken part in like 10-15 minutes. The next time it popped again, the tech man became a prima donna and stood me up 5 times in a span of 3 months. So 3 months I had no music. That was the last straw and I traded them in (as is) to a local audio buy and sell trader for a brand new ARC VS115. My floor space was suddenly cleared up, 4 chassis became one. There was no way I could have hauled 4 chassis into my car to bring to a service place. Ever since, I have had only 1 chassis power amp.

 

[Audiohertz2]

There is nothing i despise more than an unreliable Product ...!

 

[DasguteOhr]

In post # 3, Gary mentioned this:

"Every single tube that they receive (they do not manufacture their own tubes) are burned in for 120 hours before being measured and matched. They they are burned in again, to ensure that the do not drift. That is why Jadis amplifiers are not easy to bias - they should be biased when new tubes are put in, and then they should be left alone."

Does this mean that even for Class A auto-bias Jadis amps, there is a new to check bias when new tubes are put in?

How does the Class A auto bias function of Jadis work? Some tech told me that it is auto biased by installing matched pair tubes. Does it mean all you need are 4 matched pairs even if the 4 pairs are not balanced to each other (in an amp that uses 4 power tubes per channel, for example).

First of all, the workmanship quality of Jadis is excellent. The construction in 3D with copper rails can't even be built in a few hours. The polished steel case is amazing.
With cathode bias, the idle current is created with a cathode resistor(red) which is bridged with an electrolytic capacitor (alternating voltage).
The gridleak resistor(blue) ensures that no grid current flows on the grid of the KT 88. This is the protection against excessive current consumption (thermal runaway of the tube. This is the rough principle of how it works.
I'll explain to you using the yes 80 circuit diagram what the catch is.
1. Jadis saves one resistor + electrolytic capacitor per pair of Kt88 tubes.
This means that if they are not matched, there is an asymmetry with a pushpull amp. A slight hum is possible or wear on the tube is not the same in the long term.If you had used this combination per tube, this problem would not arise. my opinion.
2.The grid leak resistor has been chosen too large. If you look at the data sheet of a Kt 88, it says the maximum permitted values for the respective bias method. And now the vicious circle begins that leads to damage to the amplifier and tubes.The only reason I can think of is that if you reduce this resistance to, for example, 150kOhm to be on the safe side, this means that the ECC 83 driver tube is being put under too much strain and the amplifier no longer sounds good.
Unfortunately, too high a grid leakage resistance leads to uncontrollable failures. As I said, it doesn't have to happen, but it can.
I hope I explained this somewhat understandably

 

[Argonaut]

Makes perfect sense Stephan , however we do not know the values of the bias circuit within the JA100 and perhaps this is in part where the mystery EL86 comes into play.

It would be nice were fuse protection for the bias circuit to have been implemented within the JA100 as Jadis appear to have implemented this fail safe feature in their current ranges.

Ron since you are in contact with Jadis could you not request a copy of the circuit diagram ?

 

[Ron Resnick]

Ron have you tried any of the older Cardas?

Golden Cross in particular can be a wonderful cable as a single cable to tune a system. I have a set of Golden Cross XLR and Neutral Reference XLR. Both have their charms.

No. There are too many reports of Golden Cross being just too warm for me to consider that one. It seems from reports almost like a tone control.

Are you familiar with Clear Reflection?

 

[Ron Resnick]

How is Tom doing, is he still in the business? He is an invaluable resource in the industry, going to be extremely difficult to find someone young to follow in his footsteps of knowledge and he is a character to boot.

Tom is officially retired.