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Is there some ´´the best´´5842/417

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just rumours ..

Hello Tonu,







just can tell some rumours. The 5842/417A has got a huge reputation because Arthur Loesch used it in his simplistic but very expensively built DIY preamp. And this design seems to have impressed anyone who ever has heard it. So the tube must have some merits.







OTOH, I am corresponding with several guys having tried out this tube themselves and anyone sooner or later started to talk about sonics being unpleasant or "having enough room left for wishes" and, which is of bigger interest to me, the tube being too microphonic and terribly prone to RF oscillations (a tryout on the bench concerning microphony triggered me to trade my WE417A for other tubes without ever having tried them out myself in an amp).



I know Morgan Jones favours this tube too in his book but I doubt he made sonics comparisons between different tubes. And I bet he tamed the tube somehow.





One of my buddies did not like the 5842's sonics at all and he reported he prefers the European EC8010, and AFAIR, he also reported them to be non-µphonic.



The EC8010 is the lil'sister of the EC8020 which I know from own listening experiece to be a sonic miracle. I would be not surprised if my buddy is right and the EC8010 is to be preferred to the 417A/5842 .



I decided to give it a try (the choice is narrow anyway) . As I need a quiet and high-Gm tube with one triode per envelope for my preamp's differential phono input (they have to be matched, consequently they have to be matchable; matching is pain woth doube triodes).







Maybe you too ? Parameters should not be out of the ball park and maybe you could redimension your amp's components values?







****, Bernhard, you fool, giving away your secrets too early, go and run get some EC8010! :)
 
Bernie, there is also the "Rooskie firecracker" - 6C45Pi.

There are similar to 417a or 8020, like the other high-gm tubes matching is a litttle tricky. I like their sound and they are much more available than 8020 surely. Right now I use them as driver for a 2A3 and as the line stage tube in a transformer-coupled line stage. I am thinking of trying these in a phono stage, and using their low rp to operate my filter network at a nice low impedance.

RF precautions are required for these puppies too, like the others you mention.

The good news is that, so far, no one has been able to kill any of them, despite massively ignored maximum specs. I think if you hit them with a hammer they may break, but maybe not.

-j
 
Hello Jeremy,



welcome, glad yo found this place!



Originally posted by J Epstein

Bernie, there is also the "Rooskie firecracker" - 6C45Pi.


they are no fire crackers, they are quite the opposite, if i look at the triode system i would call this heavy agricultural machine design.



Do they take sheet metal for the plate or doi they forge it out of the full :)




There are similar to 417a or 8020, like the other high-gm tubes matching is a litttle tricky. I like their sound and they are much more available than 8020 surely. Right now I use them as driver for a 2A3 and as the line stage tube in a transformer-coupled line stage. I am thinking of trying these in a phono stage, and using their low rp to operate my filter network at a nice low impedance.




Could also be worth a try for my preamp. Just a bit paranoid about Russian concept of manufacturing quality (or should i say quality mean variation) and matching them, remember, i need them for long-tailed pairs.




RF precautions are required for these puppies too, like the others you mention.


Oh yes, as Allen Wright said, they are radio tubes loving RF and if they don't get RF, they make their own :)




The good news is that, so far, no one has been able to kill any of them, despite massively ignored maximum specs. I think if you hit them with a hammer they may break, but maybe not.


Like those 6900? they look like being usable as bullets in pumpguns, they stand 500g of shock. Specified in the data sheet. I'm sure the 6C45pi also is in this club.
 
The matching issue is a real one. I don't think it's quality so much as the difficulty of getting consistent high gm from sample to sample - Are the 8020's better in this regard? As you mention, the 'pis are built like little tanks, so they certainly weren't scrimping - the speculation is that the grid wires are platinum, for example.

But they didn't have any German engineers working on the production tolerances and machinery, so the did the best they could!

Anyway I was interested to hear from Tonu that he prefers the sonics of the 5842 in the DAC tube stage position. I guess it's one of those flavoring things - peach is better than vanilla sometimes, but sometimes chocolate beats either one.

To bring it back to the initial question then, I hear very few people complaining about real Western Electric 417As - those that can find them. I haven't used them myself, I'm too much of a cheapskate.

Be prepared to empty your checkbook.

-j
 
µphonic 417A

Jeremy,





got a quad of 4 genuine WE 417A but was unable to locate more. Back then as today, differntial topology and hence matching was an issue for me.


I heard of those 417A µphony rumours and built a little test setup to test it, a CC amplifier stage with a huge plate resisitor to have some amplification. my scope was hooked on the tube's plate.


I applied bias, B+, heater current, waited some minutes. Then i carefully knocked the tube's envelope and observed the knock's step response on the scope screen. A considerable step resonse! Consistent for all 4 tubes, about the same amplitude, about 3-4 times as high as CCa/E88CC from Siemens showed in comparison. So, dunno if other 417A/6842 are worse and less consistent in µphony, haven't tested them, but for my taste it is too much.





I lightheartedly let them go, traded them for ED8000. Do you know the ED8000? You wanted to eat them on a sandwich :) , was Aarhus2000
 
My CD player

I try add the schema where use Raytheon 5842Q.



Tõnu
 

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Microphony:

I have had microphony riding on parasitic oscillation - it made the appearance of terrible microphony when it was actually not the real problem. Remove the parasitic oscillation and the microphony becomes more "normal" in scale. Same thing has happened to me with hum.

Possibly this was infecting your test setup? Is your scope fast enough that you could inspect for the oscillation directly?

I may sound like a broken record (deep groove Blue Note?) but the probablility of oscillation with these high gm tubes is very high and I have been bitten by it in the past.

-j
 
Jeremy,





cannot say what it was, maybe you're right. but altleast, I used gridstoppers of 330Ohms soldered tight to the socket, (more than Allen wright recommends but i in a hurry and had not any 100 Ohm at hand)


well, if 330 Ohms do not kill oscillation, what then kills it?





And, my scope goes over 100MHz, i prefer to have switchable BW limitation; can switch it off. Although i admit, i was not searching at 100MHz, i scanned AF and some 100 kHz only (to see the BW of the step response). Snort! scope with 10 or 20MHz BW, nothing i would recommend :)





Anyway, WE417A are made of either unobtainium or costtoomuchium :)
 
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