Why not a manley snapper mono amps 110w from 4× el34 with a much better drive stage ecc83+ecc 182/5867 tube that kicks.
That is a very interesting idea I had not thought of! Thank you!

I assume these are Class AB, however.
 
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That is a very interesting idea I had not thought of! Thank you!

I assume these are Class AB, however.
Class AB in jadis too the screen grid of the pentodes is not placed on the anode for triode operation. In triode mode only 30-40% output power.class Ac50b96_bb56d324422d48e796243c0c27a4a1b9~mv2.jpg
 
Class AB in jadis too the screen grid of the pentodes is not placed on the anode for triode operation. In triode mode only 30-40% output power.class AView attachment 117185

I am not sure what you are saying. Jadis JA200 and below is Class A. That's why 10 KT88s yield only 160 watts. Ten EL34s probably yield 100 watts.
 
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Look at the datasheet this maximum power out one pair kt 88 tubes in pushpull triode.
5 pair ×27 watt.20230926_200312.jpg
If you operate the tubes like this, the tubes won't even last half a year. I think if it can manage ja 200 ~ 120 watts class A at 8 ohms permanently, that's great. But I think less so. Maybe I'm totally wrong, then ignore me.
P.S. with El34 max 90watt works
 
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I just got off the phone with Angela Cardas and Brian von Bork. They offer an RCA connector that has no rhodium.


IMG_8817.jpeg


Are the anti-rhodium people happier if I order this connector on the custom long Clear Reflection interconnects? Thank you!

PS: Clear Beyond cannot be ordered with this connector.
 
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Look at the datasheet this maximum power out one pair kt 88 tubes in pushpull triode.
5 pair ×27 watt.View attachment 117187
If you operate the tubes like this, the tubes won't even last half a year. I think if it can manage ja 200 ~ 120 watts class A at 8 ohms permanently, that's great. But I think less so. Maybe I'm totally wrong, then ignore me.
P.S. with El34 max 90watt works

I am afraid I don't understand. Is 80 to 100 watts from 10 EL34s operating in Class A implausible to you?
 
Ron, why don't you put a switch inside for the cathode resistor? What's funner than a 370VDC amp on a switch rated for 28-250VDC? Then you can stick paper clips in to flip it.
 
Ron, why don't you put a switch inside for the cathode resistor? What's funner than a 370VDC amp on a switch rated for 28-250VDC? Then you can stick paper clips in to flip it.

I have no interest in DIYing a stock amplifier.

I never expressed any interest in being able to switch with a toggle switch. It's another idea from someone else which has taken on a life of its own on this thread.
 
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Hi Folsom,

Does the Cardas RCA connector pictured above solve your brightness concern?
 
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No; but I believe in headroom in a way that I think you do not.

At 80 JA100 watts, listening at 95 to 97 dB peaks, Don thinks he heard a little bit of running out of gas on Mahler's 3rd symphony.
I believe you can relatively easily estimate it, especially since your ribbon isn’t doing bass. If it is 87dB at 1 meter you get 93dB for a stereo pair for a watt. If your peaks are, let’s say 99dB then you need like 4 watts at 1 meter. Being a line source it drops less rapidly and you lose let’s say 5dB at the listening position (you could easily measure the drop from just in front of the speaker to listening position). This means something like 16 watts for the extra 5dB. A 50 watt amp gives a 3x power headroom or around 5dB extra. My guess is the drop with distance is less so this is probably an overestimate on the power requirement.
 
Maybe Absolare SET is plausible? :D
 
I don't consider that to be a "mess." In high-end audio electronics I actually prefer point-to-point wiring over circuit boards.

I also prefer point to point in tube amplfiiers. But after owning the excellent work of Ralph Karsten point to point Atmasphere's any one will consider the work shown in the pictures a real mess. Try replacing any component in the small tube section. Fortunately some other Jadis models seem to have a much better layout.
 
I am afraid I don't understand. Is 80 to 100 watts from 10 EL34s operating in Class A implausible to you?
More than 90 watts class A with 10 El 34 per channel is not possible. The tubes then run hot with too much current.
Exsample Maximum load capacity EL34 = 25 watts
Jadis runs at 465volt (anode b +) x maximum idle current 45mA = 21 watt
I wouldn't increase the current any further, otherwise the tubes would be used up too quickly. That is a value that I use myself for my EL 34 power amplifier. A pair of EL 34 Power in push-pull triode results in approx. 16-17 watts of output power at the specified idle current. Jadis 200 has 5 pairs ~ 90 watts
 
More than 90 watts class A with 10 El 34 per channel is not possible. The tubes then run hot with too much current.
Exsample Maximum load capacity EL34 = 25 watts
Jadis runs at 465volt (anode b +) x maximum idle current 45mA = 21 watt
I wouldn't increase the current any further, otherwise the tubes would be used up too quickly. That is a value that I use myself for my EL 34 power amplifier. A pair of EL 34 Power in push-pull triode results in approx. 16-17 watts of output power at the specified idle current. Jadis 200 has 5 pairs ~ 90 watts
Thank you. 90 watts would be okay.

i just don't know if I would prefer JA200 EL34 or MastersounD PF100 or 833 or Absolare PSET -- or Absolare SET! o_O
 
More than 90 watts class A with 10 El 34 per channel is not possible. The tubes then run hot with too much current.
Exsample Maximum load capacity EL34 = 25 watts
Jadis runs at 465volt (anode b +) x maximum idle current 45mA = 21 watt
I wouldn't increase the current any further, otherwise the tubes would be used up too quickly. That is a value that I use myself for my EL 34 power amplifier. A pair of EL 34 Power in push-pull triode results in approx. 16-17 watts of output power at the specified idle current. Jadis 200 has 5 pairs ~ 90 watts
Interesting that in the Jadis France site, the 200MKII is described only with KT150 power tubes, with output at 160w. The Italian site mentions the 3 kinds of power tubes to be chosen from and their corresponding prices. The description says 160w and as a reader, I would assume that the 3 types of power tubes all yield the same 160w, all at Class A. To me, there is a big difference from 160w to 90w. This is the kind of vagueness I have encountered with my Jadis PA100 amp. Its site said manual bias but there are no pots or holes , nor instructions in the owner's manual as to how to do the manual biasing. Vague.

And Thomas Norton has tested the old JA200 as giving 130w in tech bench measurements in the review of Dick Olsher in Stereophile in the 1990s.
 
Interesting that in the Jadis France site, the 200MKII is described only with KT150 power tubes, with output at 160w. The Italian site mentions the 3 kinds of power tubes to be chosen from and their corresponding prices. The description says 160w and as a reader, I would assume that the 3 types of power tubes all yield the same 160w, all at Class A. To me, there is a big difference from 160w to 90w. This is the kind of vagueness I have encountered with my Jadis PA100 amp. Its site said manual bias but there are no pots or holes , nor instructions in the owner's manual as to how to do the manual biasing. Vague.
Each type of tube has a different load limit. exsample the power supply of your amp always outputs the same voltage 465volts your cathode resistance is also a fixed size. Jadis specifies the output power in class A with the largest possible pluggable tube.
El 34 ~25watt
Kt 88~35 watt
Kt 150~ 70 watt
Theoretically you could operate the KT 150 with twice the current of kt 88. Downwards with el 34 it becomes difficult if a kt 150 was previously installed.
Too high current would kill the EL34.
First the anode plates in the tube start to glow red, a sign that the amplifier should be turned off immediately. If you ignore the white glow then everything is too late, the tube and other components are dead.therefore adjust the cathode resistance.
 
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Each type of tube has a different load limit. exsample the power supply of your amp always outputs the same voltage 465volts your cathode resistance is also a fixed size. Jadis specifies the output power in class A with the largest possible pluggable tube.
El 34 ~25watt
Kt 88~35 watt
Kt 150~ 70 watt
Theoretically you could operate the KT 150 with twice the current of kt 88. Downwards with el 34 it becomes difficult if a kt 150 was previously installed.
Too high current would kill the EL34.
First the anode plates in the tube start to glow red, a sign that the amplifier should be turned off immediately. If you ignore the white glow then everything is too late, the tube and other components are dead.therefore adjust the cathode resistance.
I read also in this thread that the old JA200 amps with factory 6550s/KT88s can be fitted with EL34s without any adjustment inside it. I wonder how that can happen given that you mentioned there is a 10watt difference between the 2, or is the 10w too small and is negligible?
 
I have no interest in DIYing a stock amplifier.

I never expressed any interest in being able to switch with a toggle switch. It's another idea from someone else which has taken on a life of its own on this thread.

You think I was being serious?

Hi Folsom,

Does the Cardas RCA connector pictured above solve your brightness concern?

I'd give it a shot. Maybe it isn't the first thing I'd reach for but I wouldn't expect negative results.
 
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I read also in this thread that the old JA200 amps with factory 6550s/KT88s can be fitted with EL34s without any adjustment inside it. I wonder how that can happen given that you mentioned there is a 10watt difference between the 2, or is the 10w too small and is negligible?
Cathode resistor (current) is calculated to work for both types.
In this case the EL34 will probably operate more linearly with higher current cleaner sound closer to the load limit .
the KT 88 will sound warmer with more harmonic distortion at lower current.
 
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I just received eight Siemens EL34s.

I just don't know if I can pop them into the JA100s without any modifications.
And why would they need that? Jadis amps are designed to work with all pentodes. KT90s are/were drop in replacements for KT88/6550. Reach our to Jim McShane and he might help you.
 

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