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I would appreciate input on choosing a great DIY phono stage to use with the following. Music is mostly Jazz & Blues. Up to $2,500 in component parts is OK.My preamp is a Berman 76 from Sound Practice issue 13. Currently I am using a battery biased 6LS7 RCA phono stage with Lundahl LL9206 step up trannies for the Denon 103. I would like to upgrade the phono stage if possible. DIY only.
Other equipment is Angela 91 300B mono blocks with beefed up power supply (additional 100uf + 10 hy choke). Speakers are Klipsch Jubilee clones. TT is VPI Aries II.
What about Allen Wrights FVP5? Other suggestions?
Additional equipment specs: The following is based on my limited knowledge and may not be accurate.
Input impedance of Berman 76 ~270K
Output impedance of Berman 76 ~320 ohms
Input impedance of the current phono stage ~47K
Input impedance of Angela 91 ~221K
Some measurements I took they may be helpful:
Voltage measurements were all with HP Digital Multimeter. These test were done with an Alps 250K volume control in the 76 which has been replaced with a 100K Daven stepped attenuator, 19 step 2db/step with a series 150K resistor for phono to maintain the 220K min. required by the RCA phone stage.
1Khz test tone @ .421 vac into 76 Pre amp from a test pink noise CD WE-91 starts to clip @ 7.75 vac at it's output into an 8 ohm resistor, per my scope, with an output from the 76 @ .603 vac into the input of the WE-91, which is right at 50% on the 76 volume control.At 75% on the volume of the 76 it is putting out 2.22 vac and at 100% on the 76 volume it puts out 2.79 vac. No clipping was observed on the 76 output at full volume.
Follow Ups:
Don't like to toot my own horn but I published a DIY phono stage, based on JC Morrison's design from Sound Practices No. 3 and 4, in AudioXpress in January and February 2004. The mods to the audio circuitry consisted of a much better RIAA EQ (within 0.1 dB of ideal) and substituting a 6J5 third stage for the 6N7 or 7F8 tube originally specified, plus a choke power supplies for B+, filament and first stage constant current source. B+ supply used damper diodes for rectification. Sounds good to me but of course I'm biased.
Hi!With that kind of budget you should go for a LCR EQed design as other suggested already. Pleanty of LCR coils available these days. Such a design will make you want to upgrade your linestage and power amps afterwards :-)
Obviously a GREAT choice! (grin)And for your budget you can actually get a full kit for it's latest version, the SVP-1.
More info if you mail me privately:
vacuumstate(at)bluewin.(dot)ch
Another option that has intrigued me for awhile is the Thorsten E810F LCR design. A link to it is in this forum somewhere. I have not built this myself but I've thought about it a lot!I just seem to like high Gm pentodes with lots of current running through them, they can be extremely quiet and are quite linear with the right OP.
JohnSilk has LCR RIAA Phono filters.
Above is their recommended circuit.
I am intrigued by this design with 6SL7s.
I would replace the mu stages with "super mu" stages
(SRPP circuit with choke in upper resistor position).
The LL1668/5mA would be great in that position.
This gives you almost full mu gain and 600 ohm Zo.
This would be my second choice for a phono stage.DanL
Dan,What would be your first choice?
Would the phono stage be a good match for my Berman 76 line stage?
Could redraw the schematic for me with the changes you suggested?
RigmaAs I posted below the K&K Phono Kit.
http://www.kandkaudio.com/phonostage.htmlEmail me for the schematic
(Click on danlaudionut above)DanL
Hello folks
I´ve built a modified version of it with Borderpatroldesigned choke-input PSU with one psu-section per tube: 8powerx-formers,40 chokes and integrated tx103mc and 102TVC.
Sounded far better than my Io from Aestehtix
IMO
Best
Leif
Norway
I have heard the Io and even aspired to own it, but the price is outrageous.Thorsten's design has also been tempting. Guess I'll have to try it.
Thanks for the insight.
I recently changed the triode wired d3A to pentode in my phono stage and liked very much the result.
nt
I used the same anode resistor, 4k7 and added only the screen supply. The voltages came out very close to the data sheet. Changed nothing else. I didn't measure the gain but there was more. 3 clicks less on the volume control (TVC) so about 6dB more gain. Knowing the OP point, I guess you could work it out from the data sheet but I don't need to know hence I didn't bother :-)
I don't know if this qualifies for DIY because it's a kit :
http://www.kandkaudio.com/phonostage.html
When I get the money it's the one I'll get.DanL
Check out JE labs website. He has some good phono pre designs that will cost you alot less than $2500. I am using one with his preamp design and it sounds great.
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