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Very accurate MC phono preamp on proto-board

101.181.10.77

Posted on May 21, 2015 at 04:54:30
mwhouston
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I now have made quite a few of these very compact and great sounding phono preamps. This is the neatest and best build to date. I need to remember how I did this because I don't think this it will be the last. This is for MC only. The differential PS is on board. It runs on 3 X 9V batteries. I call it "Mimic".
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Care to share the schematic, or are you planning loftier goals?, posted on May 21, 2015 at 05:29:11
Dman
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Just wondering...

Dman
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RE: Care to share the schematic, or are you planning loftier goals?, posted on May 21, 2015 at 05:56:47
mwhouston
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It is on diyaudioprojects forum. Free to public for non-commercial use. Bruce Heran of oddwatt fame designed and measured it. You will need to be a member to access the schematic. Look under LOMC phono preamp.

PM if you want a link.
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RE: Very accurate MC phono preamp on proto-board, posted on May 21, 2015 at 08:57:11
A.Wayne
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Include a low voltage led, the sound will deteriorate as the supply voltage drops...



Regards..

 

Thank you!, posted on May 21, 2015 at 09:52:25
Dman
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BTW- enjoying the SDS 254 so far. Listening, followed by more listening, and then listening again(as well as developing an opinion)...

Cheers,
Dman
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RE: Thank you!, posted on May 21, 2015 at 15:40:58
mwhouston
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SDS 254?
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RE: Very accurate MC phono preamp on proto-board, posted on May 21, 2015 at 15:47:18
mwhouston
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The chip on board, the OPA 2134, can work down to +\- 2.5V. The LED draws 200uA. It has a 100K limiting resistor. I generally change batteries when supply is down to 21V. A 9V battery is considered flat at 7V.

I have built a number of headphone amps with same chip which runs successfully on one 9V battery.
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RE: Very accurate MC phono preamp on proto-board, posted on May 21, 2015 at 16:00:36
A.Wayne
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I have found the high voltage has better sonics, i guess from more swing and headroom, i could always tell when batt voltage fell even by 2 volts, you are running 27 volt which is good most only run 18 , at 18volt it's pretty obvious.


 

RE: Very accurate MC phono preamp on proto-board, posted on May 21, 2015 at 16:22:13
mwhouston
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The 27V is split so the chip sees about +\- 13V. It only has to deliver a swing of 2V so well within limits. The chip could swing with this voltage about 20V but not needed. I think there is a ton of head room.
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RE: Very accurate MC phono preamp on proto-board, posted on May 21, 2015 at 16:34:14
A.Wayne
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you should see what pops do, recovery is a bitch, try it with a lower supply and see..

 

RE: Very accurate MC phono preamp on proto-board, posted on May 21, 2015 at 16:39:56
mwhouston
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I get your drift.
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Linn made a CD player named "Mimic"..., posted on May 21, 2015 at 19:23:57
Which they said was"accurate" as well. All roads lead to Rome...or Glasgow anyway.

 

or built for 12.99, posted on May 21, 2015 at 19:37:20
Awe-d-o-file
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on the bay with lots of loading options via DIP switches.


E
T
ET

"If at first you don't succeed, keep on sucking till you do suck seed" - Curly Howard 1936

 

It;s an SDS amp with a 254 amp module. Half the power of the 470... nt, posted on May 21, 2015 at 20:42:33
Dman
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nt
Dman
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Actually that's MimiK with a 'k'..., posted on May 21, 2015 at 20:59:38
kuma
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IIRC, it *mimic* the sound of LP12.

It was an excellent performer and it beat many of 1500$ contenders I have listened to back then.

 

RE: Linn made a CD player named "Mimic"..., posted on May 22, 2015 at 00:05:43
mwhouston
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This design has been measured. It tests better than 0.25db follow of the EQ curve.
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LOL, it's ALWAYS with a "K"..........., posted on May 22, 2015 at 01:28:05
Ozzy
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nt
Don't worry about avoiding temptation. As you grow older, it will avoid you.
- Winston Churchill

 

Is that a Dog Tag on top?, posted on May 22, 2015 at 08:57:31
jedrider
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I was wondering how to decorate/sign my DIY equipment. I am going to visit the Pet Store and if they have polished brass, then just great.

 

I was not calling into question the accuracy of your design..., posted on May 22, 2015 at 09:56:04
or that of the Linn for that matter as I have not measured, nor listened to either.

Of course, RIAA accuracy is a one dimensional look at the overall accuracy of a phono stage, both dynamic and static distortion and the specta of that distortion, noise and the spectra of that noise, dynamic compression, rise time, etc would all be contributory to the accuracy of the device.

 

Kuma, I should know better...., posted on May 22, 2015 at 12:14:12
My last name is Kohn, and everyone wants to spell it with a "C". If you don't watch out I'll be calling you Cuma.

 

If you can use (5) or more check out this type of service..., posted on May 22, 2015 at 13:41:12
With shipping the finished/engraved tags (5-minimum order) run $11-$12 each.

Made gobs of pet tags @ PetCo over the years and some look OK, while some look like crap (depends upon how well the machine is maintainedI guess).

If you have a local Trophy shop I'd check that out to.

 

RE: Is that a Dog Tag on top?, posted on May 22, 2015 at 15:45:02
mwhouston
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These are done by an engraver and are solid bass. Each one hand engraved,
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RE: I was not calling into question the accuracy of your design..., posted on May 22, 2015 at 15:45:53
mwhouston
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Amen brother.
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lol! (nt), posted on May 22, 2015 at 23:24:30
kuma
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.

 

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