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-   -   build phono preamp around urei phono card (http://www.wavemusic.com/community/showthread.php?t=8966)

thecitynever 05-06-2009 03:54 AM

build phono preamp around urei phono card
 
Do you think it is much work to build an external phono preamp using a urei phono card? Do I just have to solder some connector to it and supply power?

Mistick Krewe 05-06-2009 11:51 AM

I would think this idea is very do-able....

I've thought about it recently also...

would think it's also doable with Bozak phono cards...
(or probably any modular card based preamp circuit, generally)


keep us posted...

thecitynever 05-06-2009 04:50 PM

I don't have any info on that and also no phono card, but I would consider getting one, if I knew, if all I need is already on the phono card. I'm not sure
if all the processing, like ria equalisation, is done on that card.

jnkarrik 05-06-2009 05:33 PM

All the RIAA equalization is done on the card - phono in, line out. You just need a power supply with 18V.

Special.K 05-06-2009 09:32 PM

If you don't have the phono card it sounds like a costly idea, I think you could get a better phono stage from a HiFi shop for the same dollars!!

thecitynever 05-07-2009 03:41 AM

Quote:

Originally Posted by Special.K
If you don't have the phono card it sounds like a costly idea, I think you could get a better phono stage from a HiFi shop for the same dollars!!

I always thought, that if this is one of the best mixers in the world, then the phono preamp must also be very good.

Pern 05-07-2009 04:07 AM

The Phono Card design of the 1620 is a very simple one. But it's not a bad one.

If you already have a mixer in the mid/upper price range then you probably already got a better one.
Building the PCB cost almost nothing, It's the enclosure and the PSU that cost.

If you want some really hi-grade phono amp. Go for a discrete version.

deep_bias 05-07-2009 05:08 AM

you might also check this out, pretty much the same design (one less op amp), very simple (as the title suggests):
http://www.geocities.com/rjm003.geo/.../diy_pho5.html

there are a lot of DIY phono pre stages around online if you look. this one is suuuper simple tho with lots of helpful pictures. depending on what you want, i don't find small enclosures to be that expensive; you can get a small aluminum or steel one for under $15 easily on digikey or somewhere. shopping for a rack mount tho starts to cost.

Special.K 05-07-2009 12:27 PM

Looks like people beat me to it.
I don't have a problem with the phono cards in the 1620 it's just if you have to buy the cards, enclosure, psu and connectors you might find you can get a better one for the same money especilly if you buy a kit form one to save some bucks!

Mistick Krewe 05-07-2009 01:30 PM

Quote:

Originally Posted by thecitynever
I always thought, that if this is one of the best mixers in the world, then the phono preamp must also be very good.


Urei also made some external phono preamps...

they have adjustment pots,
never heard one...

but they go for very reasonable money occasionally

djone 05-07-2009 02:08 PM

Quote:

Originally Posted by thecitynever
I always thought, that if this is one of the best mixers in the world, then the phono preamp must also be very good.


I agree on the first point, but not on the second. There are much better phono preamps than the one inside the urei 1620 affordable on the market. Personally I retired the phono cards from my Urei and I use Lehman Audio Blackcube SE phono stages. This makes a huge difference & I enjoy my Urei even more.

Digitalis 05-07-2009 02:39 PM

The radio station I worked at used Urei 1122 preamps. We used them because they were one of the few units that had balanced outputs. I think they sounded pretty good but it is a little hard to tell with all the processing that occurs on the way to your radio transmitter. The 1122 uses transformers on the outputs to balance the signal so expect some of the same transformer sonics as a Urei 1620 balanced output. However, the circuitry inside the box is worlds better than what is inside a 1620.

bassbindevil 09-18-2012 01:08 AM

(If anyone still cares) If you look at the schematic of the 1122, you'll see that the basic phono stage is about the same as a $20 Radio Shack phono preamp, and if you look at the spec sheet, so is the performance. 0.5% THD, 60 dB hum and noise, and 42 to 50 dB channel separation are not indicative of "highest quality".

The Bozak uses one more transistor per channel, which I suspect is still not enough to deliver the same performance as the 1622 board which has two op-amps.

Check out the AudioXpress review of budget phono preamps, available as "403hansen2090.pdf". (Can still be found online using Archive.org.) The clear winner was the Hagerman Bugle, which is available in kit form. If you happen to search eBay for RIAA and OPA2134 you'll find what appear to be clones of the Bugle.

As to the original question, I've been intending to build a clone of the 1622 to use when digitizing my old records. Probably with the option of using two dual op-amps instead of the quad, space to use a film capacitor for the 10 uF caps, and no output cap. If DC offset is a problem, maybe add a DC servo to null it out. Based on how little progress I've made so for, it's more likely that I'll opt for one of those Bugle clones.

darrylfunk 09-19-2012 10:57 AM

i think djone is on the one....as is pern.

you can do better with less hassle.

i'd look at a basic rega fono or a creek, cambridge audio azur etc.....

i have a pair of heed phono stages and they are hard to beat if you want a hint of warmth but still have depth and speed....

my faves.

Mehdi 09-24-2012 09:43 AM

Ive made a Phono pre based on the bozak design, it sounds very nice, the line out is quite loud too, great for listening, ripping vinyl and sampling.




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