Long ago I made a few for my personal use, unfortunately I have long since lost the artwork (which was proprietary to the tool used to make it anyway) and have no plans to recreate it at this time due mainly to lack of time and probable lack of interest. I tend to wire most of my prototypes as point to point - nothing in the pre-amp or power supply is terribly complex and could be built ptp with just some thought and planning.
All of this said if someone were to be interested in putting this stuff on a couple of PCBs I would have no objections provided it was for the community and not for profit. I would just ask that I get right to approve and suggest needed revisions to artwork prior to board fabrication.
All of this said if someone were to be interested in putting this stuff on a couple of PCBs I would have no objections provided it was for the community and not for profit. I would just ask that I get right to approve and suggest needed revisions to artwork prior to board fabrication.
Hi kevinkr.
Looking through Mouser insane huge catalog where a lot of CPC connectors don't list maximum voltage ratings, do you know which one you have used..
Mouser is one of my favorite suppliers as they have free shipping to Europe when order above 50 Euro.
/Thanks Michael.
You should be able to use any of the available CPC connectors at these voltages.. I am using just one of the little 14 pin versions.
I have one minor change that I thought I would pass along to the few people I know are building this design.
I have changed C9 in the mu-follower from 0.1uF to 0.33uF because increasing the size of this cap seemed to improve the bass quality slightly. The original value resulted in an F3 in this stage of about 1.6Hz, but nonetheless the larger value seems to provided some limited benefit.
Likewise the design would probably benefit from an increase in the value of C1 to 0.33uF or even 0.47uF, provided the turntable used does not produce excessive rumble.
I have changed C9 in the mu-follower from 0.1uF to 0.33uF because increasing the size of this cap seemed to improve the bass quality slightly. The original value resulted in an F3 in this stage of about 1.6Hz, but nonetheless the larger value seems to provided some limited benefit.
Likewise the design would probably benefit from an increase in the value of C1 to 0.33uF or even 0.47uF, provided the turntable used does not produce excessive rumble.
Attachments
Hi Kevin,
Good to see that you are still refining the phono stage. However, 6n23p prices are not the cheapest on ebay. I wonder if you have some 6n24p? A comment by Wavebourn in another thread got me to check this tube. According to Klausmobile it should be resonably similar to 6n24p although with a different pin-out.
Mogens
Good to see that you are still refining the phono stage. However, 6n23p prices are not the cheapest on ebay. I wonder if you have some 6n24p? A comment by Wavebourn in another thread got me to check this tube. According to Klausmobile it should be resonably similar to 6n24p although with a different pin-out.
Mogens
Hi,
These valves are not the same .They are variable mu valves for cascade use in AGC devices for instance. It may work but short of trying, hard to tell.
Have you considered the Russian 6N1-P ?
See also :
http://www.diyaudio.com/forums/tubes-valves/36412-ecc89-ecc189-2.html
Cheers, 😉
These valves are not the same .They are variable mu valves for cascade use in AGC devices for instance. It may work but short of trying, hard to tell.
Have you considered the Russian 6N1-P ?
See also :
http://www.diyaudio.com/forums/tubes-valves/36412-ecc89-ecc189-2.html
Cheers, 😉
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Hi Frank,
As far as I know is the 6n1p not at all similar to the 6n23p, although many ebay listings says it's similar to 6dj8. I'm not sure if the 6n24p is actually a variable mu valve. Klausmobile doesn't mention it. He actually says it's looks and test very close to the 6n23p.
Cheers,
Mogens
As far as I know is the 6n1p not at all similar to the 6n23p, although many ebay listings says it's similar to 6dj8. I'm not sure if the 6n24p is actually a variable mu valve. Klausmobile doesn't mention it. He actually says it's looks and test very close to the 6n23p.
Cheers,
Mogens
Hi,
Yeah.... That's the eternal problem with these russkie valves, no clear info.
Fact remains that the heater current of this 6N1P is about twice that of the 6N23-P.
Svetlana does state it as an equivalent of the 6dJ8 whereas most Western-European vendors claim it to be closer to the ECC85.
I'll try to find more info on this 6N24-P valve but if it's an equivalent of the ECC89 then at least one triode should be of the vari-mu type.
From experience I suspect this 6N24-P to be the vari-mu variant of the 6N23-P, I just need to find some proof now. 😉
In the past I've tried a lot of ECC89's in audio circuits and most of the time the results weren't any good.
Cheers, 😉
Yeah.... That's the eternal problem with these russkie valves, no clear info.
Fact remains that the heater current of this 6N1P is about twice that of the 6N23-P.
Svetlana does state it as an equivalent of the 6dJ8 whereas most Western-European vendors claim it to be closer to the ECC85.
I'll try to find more info on this 6N24-P valve but if it's an equivalent of the ECC89 then at least one triode should be of the vari-mu type.
From experience I suspect this 6N24-P to be the vari-mu variant of the 6N23-P, I just need to find some proof now. 😉
In the past I've tried a lot of ECC89's in audio circuits and most of the time the results weren't any good.
Cheers, 😉
I try to avoid vari-mu tubes in my designs even though at these very low signal amplitudes you can sometimes get away with it. I had understood that the 6N24P was a variable mu type in at least one section, but did not go further than that.
FWIW I am not very impressed with a variety of 6N23P I have tried, very unrefined sounding.. (Mostly Reflektor) I have Telefunken and Amperex ECC88/E88CC which I much prefer. I believe SY would tell you that the modern JJ ECC88 is not too shabby either - I have some and they were better sounding certainly than the 6N23Ps on hand, although not as good as my NOS ones.
I have also come to a bit of an epiphany about many of the Russian caps, lots of bang for the buck, but not always the right part. I have removed most from the audio path and replaced them with TRT dynamicaps. The teflon EQ caps will be replaced with REL RT types matched to 1% between channels and 2% absolute tolerance, mainly to get away from the metal case. (Otherwise they are great capacitors but here the capacitance to surroundings is a problem. The new ones will be in free air rather than secured to the chassis.)
FWIW I am not very impressed with a variety of 6N23P I have tried, very unrefined sounding.. (Mostly Reflektor) I have Telefunken and Amperex ECC88/E88CC which I much prefer. I believe SY would tell you that the modern JJ ECC88 is not too shabby either - I have some and they were better sounding certainly than the 6N23Ps on hand, although not as good as my NOS ones.
I have also come to a bit of an epiphany about many of the Russian caps, lots of bang for the buck, but not always the right part. I have removed most from the audio path and replaced them with TRT dynamicaps. The teflon EQ caps will be replaced with REL RT types matched to 1% between channels and 2% absolute tolerance, mainly to get away from the metal case. (Otherwise they are great capacitors but here the capacitance to surroundings is a problem. The new ones will be in free air rather than secured to the chassis.)
Hi,
Hmmmm...
There's an idea... How to properly build your own gear... ???
Turret boards, stuff like that, right ?
Cheers, 😉
Hmmmm...
There's an idea... How to properly build your own gear... ???
Turret boards, stuff like that, right ?
Cheers, 😉
I have piles of them around here somewhere. I used strips for some of the components, but this was a prototype and it is classic P2P and not the tidiest implementation after three major redesigns and dozens of iterations.
I find it surprising that the statement design was so easy and yet the purportedly more modest design has taken way more effort.. Can't say I haven't learned something along the way though, including something that you and I have both known for a long, long time and that is that the components you use actually do matter. I of course deny that categorically to keep the hounds of hell at bay, of course since almost no one reads my threads anyway I expect this to go mostly unremarked.. 😀
Some of this stuff might even measurable.
I find it surprising that the statement design was so easy and yet the purportedly more modest design has taken way more effort.. Can't say I haven't learned something along the way though, including something that you and I have both known for a long, long time and that is that the components you use actually do matter. I of course deny that categorically to keep the hounds of hell at bay, of course since almost no one reads my threads anyway I expect this to go mostly unremarked.. 😀
Some of this stuff might even measurable.
Kevin, I would think that the ordinary 6n23p might be a bit too microphonic to be ideal for phono first stage; the -ev variant is structurally quite different. Have you tried it? it's a bit more expensive these days but rather cheaper than Telefunkens.
I generally use only EV types so the answer is yes, I just was too lazy to add the extension. The observation applies to them and the cheaper ones as well. Just don't like them that much. U.S. made ones for the most part are not good either, Philips family ECC88 are generally much better.
Hi,
A rhetorical question ?
In fact, my fav ECC88s are also the Philips (and daughter companies) ones.
No need for a TFK or whatever here unless perhaps you happen have a stash of Cca's.
Cheers, 😉
A rhetorical question ?
In fact, my fav ECC88s are also the Philips (and daughter companies) ones.
No need for a TFK or whatever here unless perhaps you happen have a stash of Cca's.
Cheers, 😉
Not rhetorical at all Frank; I just wonder what particular parameter(s) is/are causing a high quality valve like 6n23p-ev to sound noticeably lacking in refinement in Kevin's design.
One would have thought that the differences in intrinsic linearity of the ecc88 variants would be swamped by the fact that the lower valve in any cascode faces such a relatively steep loadline.
Hi,
Think of a cascode circuit as if it were a penthode. High gain and predominantly odd order distortion.
Have that as your first amplifying stage in a phono stage and you're bound to hear the valve really.
Transconductance at work...
Cheers, 😉
Think of a cascode circuit as if it were a penthode. High gain and predominantly odd order distortion.
Have that as your first amplifying stage in a phono stage and you're bound to hear the valve really.
Transconductance at work...
Cheers, 😉
Referring to post #24 I used TRW metal glazed RN70D resistors I had on hand for R3 cascode plate resistors. I don't know what possessed me with a desire to replace them, but I just replaced them with 2W Mills I originally purchased for this project (they've been in and out) and a mild high treble coloration that was becoming irritating with the very forward sounding Windfeld is now gone. (It was always there, but the other cartridge I use on this table is much more laid back sounding/less aggressive) I'm at a loss to explain, but I generally don't use those TRW resistors in very low level audio applications.
Also after repeated experiments with other EQ caps the Russian teflons mentioned elsewhere seem to be a good choice for this design.
Also after repeated experiments with other EQ caps the Russian teflons mentioned elsewhere seem to be a good choice for this design.
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