 
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
|
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
50.80.146.114
I installed a couple of 2.2uF Russian K75-10 caps in my 2A3 amp. Wow, they are super. Dynamic, dynamic, dynamic. Super quiet background. The caps reduced the noise floor significantly and allow me to hear more detail. Most of all, I finally have some 3 dimensionality for the soundstage.
The K75-10s replaced ClarityCap MR capacitors acting as a bypass cap on the driver tube.
Now, if I could only find some larger uF values for the K75-10s. Something like 10uF up to 40uF. I have a perfect spot for these.
Follow Ups:
2.2uF seems very low for 6C6 cathode bypass duties. It is more likely the screen bypass that is being referred to.The screen bypass of the 6C6 sounds "better" with NOS PIO (and > = 4.0uF), apparently; the changes you described are pretty-much what I'd expect.
Cheers,
91.
"Confusion of goals and perfection of means seems to characterise our age." Albert Einstein
Edits: 10/24/16
"The caps reduced the noise floor significantly..."
I wonder what's at play and why the noise was reduced?
Cathode bypass caps? 2.2uf total or the 2.2uf side capping a larger cathode bypass cap?
Could the ClarityCap MR have been picking up noise and the Russian K75-10 aren't?
Very mysterious....
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
The k75-10 is a bypass cap by itself. The clarity cap is completely removed. The k75-10 is on the driver tube and not to be confused with the cathode bypass cap on the output tube. Hope this clarifies.
.
"Confusion of goals and perfection of means seems to characterise our age." Albert Einstein
I recently installed a pair of these in my 2nd order HF speaker cross overs. They replaced very high priced 'boutique' capacitors and I cant say enough about them. The 'boutique' capacitors were glassy and brittle sounding. The K75-10s brought a smooth natural warmth to my system. With the K75-10s I was afraid of loosing detail and this was immediately not the case. I have about 50 hours on them and they keep getting better. Weather they are 'prime PIO' or "paper/polyethylene-terephthalate." doesn't matter....they sound great.
I read about the K75-10s somewhere on the Asylum a while ago and this is a perfect example where a 'noob' has learned and directly benefitted from your 'braintrust'
Thanks guys
Three Cheers for Russian K75-10 Caps!
I think it's interesting that one cap would be noiser than the other.
BTW 2.2uf seems like a very small size for a cathode bypass cap.I would think in most instances that only the high frequencies would be bypassed through the 2.2uf cap and there would still be local current feedback for the low frequencies.
That would shift the frequency response of the stage to accentuate the high frequencies. Kind of like a tone control.
There's a formula for calculating the value needed to cover the whole audio band.
It's complicated but I have it loaded into a spreed sheet. See link
Rp is the plate resistance of the tube at your operating point.
RL is the total load plate impedance (plate resistor in parallel with the grid resistor of the following stage).
RK is the value of the cathode resistor.
Mu is the Mu of the tube.
F3 is the -3db point of the filter.
It takes a decade to get totally out of the effects of the filter. So if you want 20Hz to be phase shift free then build the filter for 2Hz.
Most build for 3-5Hz.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 10/23/16
I have conflicting information on those. One source says the green k75-10 is "prime PIO," another refers to it as "paper/polyethylene-terephthalate." I wonder which is correct?
--------------------------
Buy Chinese. Bury freedom.
!
The Mind has No Firewall~ U.S. Army War College.
Googled it, not much comes up.
--------------------------
Buy Chinese. Bury freedom.
When I listen to PIO caps, I normally hear a slightly softer presentation with plenty of warmth and tonal color. With plot caps, which I do not like, I hear a slight synthetic-ness and a more strident sound with less tonal color. The poly caps are usually more dynamic than the PIOs. The poly caps have a slight upper midrange glare.
With the k75-10, I get the best of both worlds. I was not expecting this at all. The upper midrange glare is gone. The tonal color is there. Great dynamics. Amazingly low noise floor.
So, I don't know whether they are PIO or poly, as they don't behave like either.
Post a Followup:
| FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
||||||||||||||
This post is made possible by the generous support of people like you and our sponsors:
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2024, Audio Asylum, all rights reserved ]
