DIY Audio Projects Forum
http://diyaudioprojects.com/Forum/

Mimic, Retro-833MC - Bruce's phono preamp design.
http://diyaudioprojects.com/Forum/viewtopic.php?f=10&t=5915
Page 1 of 1

Author:  mwhouston [ 10 May 2017, 21:18 ]
Post subject:  Mimic, Retro-833MC - Bruce's phono preamp design.

Here is yet another Mimic phono stage (Mimic Retro-833MC). This time MC only and staying with the LM833 OPAMP. It was the quietest in the build and I like the sound. All on a prototype brd. including differential PS. This time in an epoxy enamel cast Al enclosure. Silver soldered and silver plated hookup wire. No shielded wire to dull the sound. Sounds solid and balanced.
Attachment:
P5113610 (800x600).jpg
Attachment:
P5113611 (800x664).jpg
Attachment:
P5113612 (800x738).jpg

Author:  mwhouston [ 14 May 2017, 09:04 ]
Post subject:  Re: Mimic, Retro-833MC - Bruce's phono preamp design.

This realy didn't work. Very long and painful story short: I converted into a Mimic MM preamp with an OPA2134 chip. All good now. Quite happy.

Author:  mwhouston [ 14 May 2017, 09:05 ]
Post subject:  Re: Mimic, Retro-833MC - Bruce's phono preamp design.

New name though: "Black Shadow".

Author:  gofar99 [ 14 May 2017, 15:04 ]
Post subject:  Re: Mimic, Retro-833MC - Bruce's phono preamp design.

Hi Mark, what went wrong with the 833s? I prefer the 2134s but the others ought to have been OK.

Good listening
Bruce

Author:  mwhouston [ 14 May 2017, 18:27 ]
Post subject:  Re: Mimic, Retro-833MC - Bruce's phono preamp design.

Building the preamp as a MC stage means, as you know, requires high gain. This came with a high level hiss. I tried three differnt chips, Burson V5i-D, LM833 and OPA2134. The worse for hiss was the Burson then the 2134 and best of all the 833. Even on low efficiency speakers the hiss was audible from listen position. Some would say it's low enough not be noticable but when I can build a Mimic MM with no audible noise and a seperate MC step-up, why put up with it.

To this end I have made the preamp a MM only and are using one of my three really good MC step-ups to do the pre-preamp work. Great combo. I have about four hours of listening with the new Mimic under my belt and am enjoying the new Mimic about to be named "Black Shadow". One: it is glossy black and two: it shadows what is in the groove. Pleased with the look and the sound. It is very compact also which adds to its cool look.

I used very standard parts, nothing special; MKTs and NP (4.7uf) caps, metal film resistors but a mil-spec machined chip socket. I have found this combo of parts sounds the best and is real easy and cheap to work with.

Author:  Felix [ 17 May 2017, 04:54 ]
Post subject:  Re: Mimic, Retro-833MC - Bruce's phono preamp design.

G'day all, yes that circuit as an MM stage is hard to beat! My favourite personal version at the moment is using an NE5532, a nice 'cool' sound and very quiet! Regards, Felix.

Page 1 of 1 All times are UTC - 6 hours [ DST ]
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/