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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".
| retro-thermionic |
Edits: 05/21/15 05/21/15Follow Ups:
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.
These are done by an engraver and are solid bass. Each one hand engraved,
| retro-thermionic |
With shipping the finished/engraved tags (5-minimum order) run $11-$12 each.
Made gobs of pet tags @ PetCo over the years and some look OK, while some look like crap (depends upon how well the machine is maintainedI guess).
If you have a local Trophy shop I'd check that out to.
on the bay with lots of loading options via DIP switches.
E
T
Which they said was"accurate" as well. All roads lead to Rome...or Glasgow anyway.
This design has been measured. It tests better than 0.25db follow of the EQ curve.
| retro-thermionic |
or that of the Linn for that matter as I have not measured, nor listened to either.
Of course, RIAA accuracy is a one dimensional look at the overall accuracy of a phono stage, both dynamic and static distortion and the specta of that distortion, noise and the spectra of that noise, dynamic compression, rise time, etc would all be contributory to the accuracy of the device.
Amen brother.
| retro-thermionic |
IIRC, it *mimic* the sound of LP12.
It was an excellent performer and it beat many of 1500$ contenders I have listened to back then.
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.
.
nt
Don't worry about avoiding temptation. As you grow older, it will avoid you.
- Winston Churchill
Include a low voltage led, the sound will deteriorate as the supply voltage drops...
Regards..
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.
| retro-thermionic |
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.
Edits: 05/21/15
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.
| retro-thermionic |
you should see what pops do, recovery is a bitch, try it with a lower supply and see..
Edits: 05/21/15
I get your drift.
| retro-thermionic |
Just wondering...
Dman
Analog Junkie
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.
| retro-thermionic |
BTW- enjoying the SDS 254 so far. Listening, followed by more listening, and then listening again(as well as developing an opinion)...
Cheers,
Dman
Analog Junkie
SDS 254?
| retro-thermionic |
nt
Dman
Analog Junkie
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