NewYorkDave

Recommendations for a killer phono preamp?
« Reply #20 on: January 10, 2005, 09:30:14 AM »
That looks like a good value for the money. I like the switchable EQ... and the fact that they had the decency to put the manual w/schematic on their website so you can see what you're buying!  :thumb:

I'm not crazy about how the stereo/mono switching is implemented, but otherwise the circuit looks pretty solid, at least at first glance.


Dan Kennedy

Recommendations for a killer phono preamp?
« Reply #21 on: January 10, 2005, 12:01:04 PM »
Yep, that's pretty close to what I use, bet it sounds good.

The circuit I use was first put together in 1974, using LF-357's and OP-17's, which are definitely long in the tooth now, but at $18 each were pretty hot stuff back then.

I always liked the split passive approach, and you can use different opamps. I always liked a real good high speed one for the first stage, just like in an I-V converter for a DA, this stage see's some high amplitude high frequency crap in mistracking, and if it doesn't deal gracefully here, the rest of the circuit won't help much.

ijr

Recommendations for a killer phono preamp?
« Reply #22 on: January 10, 2005, 04:42:14 PM »
Well, the name of topic is killer phono preamp...
I've seen and heard thing where all RIAA was done without any r-c, just output transformer.
(russian patent, hehe) :grin:
This is   the killer .
In case of great interest I will try to ask who is the author
of this invention.
"The ear is the only judge of tonal balance."
Radio Designer's Handbook, 1953, p.632.

stickjam

Recommendations for a killer phono preamp?
« Reply #23 on: January 12, 2005, 09:03:13 AM »
I checked out the Hagerman site.  He's got this one too, which appeared interesting...

http://www.hagtech.com/cornet2.html

Looks like the EQ is just as easily switchable.  Any apparent pros/cons of that one?  How could I best approach getting balanced outputs from any of those?  

Actually I've seen some designs that were balanced throughout--from cartridge to output.  I can't seem to find it anymore though.   To my eyes (long out of my tube design days) appeared that it might have difficulty interfacing to a typical SS input from an impedance standpoint, tho.   I'll pass it along if I find it.

--Bob

Dan Kennedy

Recommendations for a killer phono preamp?
« Reply #24 on: January 12, 2005, 09:51:00 AM »
I did a balanced RIAA preamp, based on the split passive original, by the time I got done disconnecting the shell of the pickup, rewiring the turntable and arm it became quite a project, but it did sound great.

Still use it in fact, whenever I get a bug up my butt to play records, most of which are from the '70's and been thru way too many parties, so don't really have that "vinyl superiority" anymore :grin:

rafafredd

Recommendations for a killer phono preamp?
« Reply #25 on: January 12, 2005, 09:54:45 AM »
You should check this out:

http://www.klaus-boening.de/

stickjam

Recommendations for a killer phono preamp?
« Reply #26 on: January 12, 2005, 12:23:05 PM »
Quote
You should check this out:

http://www.klaus-boening.de/


OMG! :shock: Holy Capacitors, Batman!    Very interesting, but I'm not sure I really need a phono pre with its own UPS.  :grin:

I found it again!  Here's the balanced tube-based preamp that seemed interesting to me:

http://www.tubecad.com/july99/page10.html

Opinions about the design?  Would this be able to feed a typical balanced line-in console input?  

If I switched out (removing from the circuit) the RIAA EQ components (I presume the 10.6K resistors and the .03uF and .01uF caps??) any idea what else would need to change to bring this to a "flat" response?

--Bob

rafafredd

Recommendations for a killer phono preamp?
« Reply #27 on: January 12, 2005, 05:03:24 PM »


Yes, it looks overkill, but you donĀ“t need to use his PSU. I just pointed to it because the circuit looks really interesting. Specially the input stage, with six parallel 2sk369 FETs...

http://www.klaus-boening.de/assets/images/Mkiii_b2.gif

It seems that one could use this input stage only, followed by tubes, instead of the opamps, or maybe go IC balanced transformerless output. Fred Forssell has an interesting floating balanced output stage in his site, using OPA604.

Anonym

Recommendations for a killer phono preamp?
« Reply #28 on: May 22, 2006, 04:25:47 PM »
Quote from: "ijr"
Well, the name of topic is killer phono preamp...
I've seen and heard thing where all RIAA was done without any r-c, just output transformer.
(russian patent, hehe) :grin:
This is   the killer .
In case of great interest I will try to ask who is the author
of this invention.


i find that sounds quite interesting. do you have more info on that?

CJ

Recommendations for a killer phono preamp?
« Reply #29 on: May 22, 2006, 08:15:04 PM »
You might check the Borbely site.
I think he even sells pricey kits and matched fets.

Here's a John Curl. (Mark Levinson)
Dead sound system guru, among aother acomplishments:



Cool interview.....
http://www.parasound.com/pdfs/JCinterview.pdf
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html


pstamler

Recommendations for a killer phono preamp?
« Reply #30 on: May 23, 2006, 04:23:36 AM »
It occurs to me, seeing Dan Kennedy's name earlier in this thread, that a couple of his Great River boards per channel, with a passive network in between them, ought to make a super-good phono preamp. Now to figure out how to put in a subsonic filter without another amplifier...

Peace,
Paul

Gus

Recommendations for a killer phono preamp?
« Reply #31 on: May 23, 2006, 09:27:47 AM »
look for an old TAA 1980 or so issue.   There was a cool Marsh preamp.

rodabod

Recommendations for a killer phono preamp?
« Reply #32 on: May 23, 2006, 11:22:13 AM »
Apologies for not knowing a great deal at all about phono preamps, but does anyoe know in which instance transformers are solely used for voltage gain?

I seem to recall thinking it was only for moving-magnet cartridges.

Also, in that case, how do you get the RIAA equalisation if you are only using transformers for voltage gain? Do you need a separate RIAA filter too?

Just wondering as I have two spare 1:10 transformers....
Quote from: tv
punchy fat bastard chip

rodabod

Recommendations for a killer phono preamp?
« Reply #33 on: May 23, 2006, 12:10:05 PM »
Ahh, my mistake. Trust me to choose the wrong one!

Well, I'll just stick what I have at the moment - Technics moving magnet plus NAD phono amp. Doesn't sound fantastic though - think I might upgrade but this is difficult on a budget...
Quote from: tv
punchy fat bastard chip

CJ

Recommendations for a killer phono preamp?
« Reply #34 on: May 24, 2006, 09:14:43 PM »
OK, I posted an incomplete schematic, so I went back for the whole enchillada>

http://vacuumbrain.com/The_Lab/TA/Free_Circuits/jc2.jpg
http://vacuumbrain.com/The_Lab/TA/Free_Circuits/jc2_a.jpg
http://vacuumbrain.com/The_Lab/TA/Free_Circuits/jc2_b.jpg

The last one is the output circuit.

cj
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

gyraf

Recommendations for a killer phono preamp?
« Reply #35 on: May 29, 2006, 01:53:56 PM »
..note to self: don't let Harman run your company..

chriss

Re: Recommendations for a killer phono preamp?
« Reply #36 on: December 28, 2009, 06:12:25 AM »
O.K. The last post is quite old, so there seems to be not too much of interest. But: All around the web the WE66 is called an RIAA-Plaback-Amp. I doubt that very much, since I have the strong suspicion that it is an Tape-head-playback-amp.
Just in case, anyone is interested...

best

ChrisT


 

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