diyAudio

diyAudio (http://www.diyaudio.com/forums/)
-   Tubes / Valves (http://www.diyaudio.com/forums/tubes-valves/)
-   -   What phono preamp with Dynaco MKIII (http://www.diyaudio.com/forums/tubes-valves/220608-what-phono-preamp-dynaco-mkiii.html)

bradberry00 28th September 2012 08:42 PM

What phono preamp with Dynaco MKIII
 
Hello All,

I was wondering what phono pre to use if I were to build a pair of MKIII's...Would like it to be tube but I am not against solid state if I can get more amp for my money. Budget would be under $500.

Thanks much,
-david

20to20 28th September 2012 09:13 PM

Anything with at least 1.6V out if you want to reach full volume.

bradberry00 28th September 2012 09:19 PM

Cool, anyone have favorites? how about phono stages with volume controls?

kevinkr 29th September 2012 01:41 AM

Take a look over in analog sources and do a search on phono stages..

The Salas Valve Itch would seem a particularly good match to your needs and is a known good performer.

I put up a detailed description of my most recent design the "Muscovite" but I suspect this design would probably be too complex and costly to meet your budget concerns.. (It wasn't that expensive to build but is complex and some parts may be expensive to get new - I benefited from a few key junk box parts.)

Eli has a re-interpretation of the classic RCA data book design with a mosfet follower on the output which would also be a good candidate IMO.

Any of these designs will drive a passive or TVC (check out Dave Slagle's TVC kits) with varying degrees of success.

Eli Duttman 29th September 2012 05:23 AM

1 Attachment(s)
Quote:

Eli has a re-interpretation of the classic RCA data book design with a mosfet follower on the output which would also be a good candidate IMO.
Thanks for the "plug", Kevin.

I've uploaded the schematic. The project can easily be brought in under the stated $500. :D Contact member Jeff Yourison and get lots of info. about building it. Given that 1.6 V. number another poster mentioned, constant current source (CCS), instead of resistive, loading of the 2nd gain block, to maximize gain, is probably a good idea. Set the CCS in the 900 to 1000 μA. range.

BTW, the pentode I/P stage of the Dyna Mark III, with its approx. 470 KOhm I/P impedance, is a good candidate for use with a passive control setup. Keep the cables between the control(s) and monoblocks VERY short/low capacitance, as in unshielded and braided. Most of the time, a passive setup has to use 10 KOhm controls and that can be quite problematic. That 470 KOhm figure allows the use of a 50 KOhm control value, which quite a few designs can drive.

Jaimo 3rd October 2012 06:16 PM

Mkiii phono mate
 
I use an Audio research SP8 with my mk iii clones and this works great!

Look at PAS3 derivatives - these will likely work well.

BZed 3rd October 2012 06:33 PM

I'm not sure that a phono amp only setup with passive VC would work that well. I think you'll need the gain of the post VC gain stage to drive the MKIII to full output. If you were driving with a CD player it would be OK in most cases. Due to the differences in phono cart. outputs and limited gain of the phono amps the extra gain will be very good to have availble.

BZed 3rd October 2012 06:35 PM

Quote:

Originally Posted by Jaimo (Post 3188854)
I use an Audio research SP8 with my mk iii clones and this works great!

Look at PAS3 derivatives - these will likely work well.

PAS3 derivitives.... now thats funny. Of course they will, they were designed to.

Eli Duttman 4th October 2012 02:26 AM

Quote:

I'm not sure that a phono amp only setup with passive VC would work that well.
That's precisely why I suggested CCS loading the 2nd gain block. A resistively loaded RCA setup yields approx. 45 dB. of net gain and that's not quite enough. CCS loading the 2nd gain block, along with buffering the O/P, will easily add 5+ additional dB. That should be sufficient to drive the Mk. 3 into clipping, when a loud passage is played back by a "typical", 5 mV., MM/MI, cartridge.


All times are GMT. The time now is 01:58 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio


Content Relevant URLs by vBSEO 3.3.2