Sy,
As I said, my knowledge is limited but I know that MM cartridges do not like capacitance - that is they like it less than MCs!
E282F is quite easily found in Europe, many of the dealers seem to have them. I have eight of them and despite not building presently am inclined to hang on to them.
I think I have mentioned before that I got into all this because I love the valves themselves. In my active period I found another one that's worth a look, but very, very difficult to find. This is the 7150 also listed as A1600 in the Vade-Mecum Unusually, it is a pure tetrode with a B9G base (like 437A). Strapped as a triode it provides mu of 30 and gm of 30 or thereabouts. They were made by Ericsson in Sweden - again I have eight of them!
7N7
As I said, my knowledge is limited but I know that MM cartridges do not like capacitance - that is they like it less than MCs!
E282F is quite easily found in Europe, many of the dealers seem to have them. I have eight of them and despite not building presently am inclined to hang on to them.
I think I have mentioned before that I got into all this because I love the valves themselves. In my active period I found another one that's worth a look, but very, very difficult to find. This is the 7150 also listed as A1600 in the Vade-Mecum Unusually, it is a pure tetrode with a B9G base (like 437A). Strapped as a triode it provides mu of 30 and gm of 30 or thereabouts. They were made by Ericsson in Sweden - again I have eight of them!
7N7
How about ECC807 - high mu, 150, for use in high gain preamp - I have three of these in a working Rogers Cadet III. I've rebulit the power amp part that uses two ECL86 tubes into a "baby Huey" with fabulous results.
Just wondering if could get better phono amp with the ECC807s?
Just wondering if could get better phono amp with the ECC807s?
SY said:
I'm not sure I understand why. Take the 6F5 for example, mu=100, no grid capacitance exceeds 6pf, and since it was a common choice for microphones and reel-to-reel playback electronics presumable the noise/microphony parameters are in the ballpark. In the spirit of 7n7's post, what am I missing?
Well, in grounded cathode, there's 250pF of Miller; that's lower than most high mu tubes will give, but still on the problematic side for the Shure or many other MMs if you include likely cable capacitance.
Majestic said:
My first impression was not great, but I need to play with them more to really have an opinion. Fwiw, my first opinion of the 6c45 was also not good, and while they are no E810F's, I am growing to like them a little more.
7N7 said:
Any suggestion for a dealer that might have some, and might ship to the states?
rdf said:
Sy will have a better answer I expect, but I should think that Miller capacitance is the problem here.
If Ca-g is 6pF and you add strays to that you'll be looking at probably 12pF perhaps more. If you get A =75 out of the valve then you're looking at 900pF ; a MM cartridge (and I suspect many MCs) would certainly not like to look at that.
7N7
dsavitsk said:
Here's one
He has them listed at 17.38 euros, which might be a little pricey but probably not much. And here's another in England this time; price quoted is £11.90. I found these in the first couple of pages in Google; I expect that there are plenty more.
7N7
anyone use a pentode? I've wanted to hear an EF86 (or other) based phono but have never experimented with it (yet).
kstagger said:
In my previous post I suggested some tricks with 6J32P that is close to EF86 and WE 310A. It works fine in RIAA pres. Long time ago I used it with passive RC EQ network and TL071 connected as a voltage follower.
I'm currently using this one:
http://www.triodedick.com/phonodude/PhonoDudeamp.GIF
The site of triodedick is in Dutch, but you can find some english translations as well.
The inputtube is a 5755 and I like this design a lot.
I attached a picture of my phono stage and turntable.
http://www.triodedick.com/phonodude/PhonoDudeamp.GIF
The site of triodedick is in Dutch, but you can find some english translations as well.
The inputtube is a 5755 and I like this design a lot.
I attached a picture of my phono stage and turntable.
Hi, i use tube preamp for sound card, i auditioned 3 preamps, one with 6N3 tube, one with 6SL7 and one with ecc88. Ecc88 has best sound "magic" gentle sound i love it, but little slow. 6N3 has "exciting" fast sound, but without "magic" of ecc88. 6SL7 has the slowest sound without "magic" of ecc88 and without "exciting" of 6N3, sound is like from cave but deep and full.
Eli Duttman said:
Hmmm. That is very interesting. In the late 1980s I designed and built a preamp that I used for several years and the phono section was built from 6GH8As simply because I had about 12 or 15 of them to choose from. The circuit was very similar to this one and I enjoyed it for some time. The line stage was a 6CG7. The power amp was a P/P 6BQ5 set. I stopped using that preamp when a balance problem developed in the phono amp. This is the only other 6GH8 phono amp I've ever seen. Thank you Eli D.
I'm really enjoying all the input on this subject. It's giving me lots to consider. So far it appears that the 6DJ8/6922/6N1P/ECC88 in cascode is a very suitable valve. Some of the others mentioned seem like they might be good too but many of them are hard to obtain or are rather expensive. At any rate, I want to do all I can to keep input capacitance down. This disqualifies 6EU7, 12AX7A, 7025 and other variants and even 6SL7, even though I've used many of these over the years. My phono interconnect cable and tonearm wiring present 134pF of capacitance. Experience has shown that lowest possible capacitance makes for best sound from MM cartridges and particularly with high inductance Shure cartridges.
Thanks to everyone for all of the suggestions.
"Sounds like some EQ differences. Have you measured this?" No no, you can see the preamps i use here.
http://www.elektronky.vyjimecny.cz/?p=p_19&sName=pøedzesilovaèe
http://www.elektronky.vyjimecny.cz/?p=p_19&sName=pøedzesilovaèe
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