With Frank back among us is only fair that I give him a project to think about.
Franks line stage project a while back was not only good reading but good learning for most of us.
Some of us have been searching thru countless schematics trying to come up with a good working quiet phono preamp.
Frank? anyone?
Franks line stage project a while back was not only good reading but good learning for most of us.
Some of us have been searching thru countless schematics trying to come up with a good working quiet phono preamp.
Frank? anyone?
Joe,
I think Frank did show a schematic for a MM phono stage many months ago, although I'm not sure if he started the thread or not. I do distinctly remember he showed a schematic for a MC pre-pre amp using 4 6922 sections paralled and running at 24 volts B+. (Stuck in my mind because I remember thinking "Man, that's gonna be a lot of tubes for a phono stage.") Sorry, I don't have time to search right now but seems like it was about the time he showed the 12BH7 line stage schematic. However, I would be really interested in anything new he comes up with. And I am definitely interested to see Stuart's new design (been hoping he'd show it to us).
Ken
I think Frank did show a schematic for a MM phono stage many months ago, although I'm not sure if he started the thread or not. I do distinctly remember he showed a schematic for a MC pre-pre amp using 4 6922 sections paralled and running at 24 volts B+. (Stuck in my mind because I remember thinking "Man, that's gonna be a lot of tubes for a phono stage.") Sorry, I don't have time to search right now but seems like it was about the time he showed the 12BH7 line stage schematic. However, I would be really interested in anything new he comes up with. And I am definitely interested to see Stuart's new design (been hoping he'd show it to us).
Ken
wa4htz
Ken,
Thanks for the info. I will start looking for the 6922 schematic.
I'm chomping at the bit waiting to see SY's phono preamp also. Hopefully Frank will treat us to something special in the way of a super MM/MC preamp.
Maybe SY will bring out the phono stage in time for Christmas. I could build it and also use it in place of a christmas tree. I'd just hang an ornament next to it and call it good.
Ken,
Thanks for the info. I will start looking for the 6922 schematic.
I'm chomping at the bit waiting to see SY's phono preamp also. Hopefully Frank will treat us to something special in the way of a super MM/MC preamp.
Maybe SY will bring out the phono stage in time for Christmas. I could build it and also use it in place of a christmas tree. I'd just hang an ornament next to it and call it good.
That is usually the case for me.
I have proven that the white ceramic sand filled ones can glow red, and survive! So can the old green ones. And that Electro Harmonix KT88's can glow red and blue at same time all while sounding pretty good.
Seriously, it is time for a new phono stage. My current one is getting pretty noisy, and it is not the tubes.
Frank presented two RIAA stage together with the 12BH7A WCF. Both have two stages build around the 7025. SY would say it has got to few tubes...Morgan Jones explains why, in the third edit...blabla
Morgan Jones's balanced RIAA preamp got 8 tubes per channel. Some are used as CCS, but there are still two sand CCS's in there, so anyone interested could hit the 10 tubes/channel figure - or even go beyound that - maybe with a tube regulated PS, but afther this
Erik
Morgan Jones's balanced RIAA preamp got 8 tubes per channel. Some are used as CCS, but there are still two sand CCS's in there, so anyone interested could hit the 10 tubes/channel figure - or even go beyound that - maybe with a tube regulated PS, but afther this
I will shut up!
Erik
My friend made a phono preamp with six 407A and 4 ECC88 tubes in there
The chassis is too big, made of stainless steel, and the power supply is bigger than as 1200VA APC UPS Sy, are those FETs readily orderable? From RS Compnents perhaps? C'mon tell me the tubes
So I will have time to find 4 of them
I've never dealt with RS so I honestly don't know. I got mine from Mouser (Supertex DN2540). You'll need to order extras to accommodate matching; I got 100 of them, split them with a friend, and had no trouble putting 6 matched pairs together from the 50 I kept. At about US$1.50 each, that's not too prohibitive.
Speaking of preamps, any thoughts on this one?
http://margo.student.utwente.nl/el/tubes/schema/preamp/fb-e180f.gif
Not sure where its from but its been on the internet for a long time now.
http://margo.student.utwente.nl/el/tubes/schema/preamp/fb-e180f.gif
Not sure where its from but its been on the internet for a long time now.
That's interesting, because I am designing a phono amp too. An hybrid casconde on the input, the lower device being a single fet for MM cartridges, and a quartet of bipolars for MC cartridges. Passive RIAA (SPICE says ±0.05dB flat from 10Hz to 20kHz) and then CCS loaded ECC88 stage (but I'm not sure about it). Will drive an Aikido linestage in the same chassis, 6CG7 + 5687 tubes
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