[cetoole]

I am going to be recording a decent amount of vinyl discs onto my computer to burn to cd, mainly for use in the car, but they will get other playtime too. Many of these discs are quite esoteric, not stuff that one can find anymore, baroque, rennissance (who's heard a crumhorn before?), and that type of stuff. I will be borrowing an older Technics direct drive TT to use for this, currently with an AT cart of unknown design, and I will be doing the recording with my EMU 1212m. Right now, what I am looking for is a relatively simple preamp for this, something that is relatively inexpensive and sounds good, whole build information, schematic, or anything is acceptable. I would want to be building this on protoboard, and I will most likely power it from a surplus EI core transformer with a LM317 regulator, unless any better suggestions can be made, while still sticking to the budget, and since I am going to be doing a bunch of LPs, I dont really wanna use batteries. I am open to tubes, discrete transistors, opamps, anything that sounds good, and is suitable for recording. There were several interesting designs in this recent thread, and the pre that Garbz posted at the end, along with several of the designs posted by Rick, all look interesting, but I am unsure what would be best for me, and as cheap as possible while remaining good. If I could keep it under $40, not counting the psu and casing, I would be happy. The last time I did something similar, I was using a ratshack pre and SB Live soundcard, and the results, while not terrible, did leave a lot to be desired. Thanks in advance for any suggestions you can give me.

 

[dsavitsk]

In your pricerange, you probably won't be able to beat this one: http://www.geocities.com/rjm003.geo/.../diy_pho5.html.

That said, assuming a decent implementation of the phono stage, the TT is going to be the limiting factor. Try to find a belt drive if you can.

 

[cetoole]

Thanks dsavitsk, I have seen that design before, I actually have a friend who has built it and likes it, but I have never heard it. As to the turntable, I would very much like to get a semi-decent belt drive, I have been looking at some of the older Thorens tables a bit, but they all seem to be more than I want to pay right now. The turntable that I will be using for this is actually my parent's, but the pre is something that I plan to use myself later when I get my own table.

 

[dsavitsk]

Quote:

Originally Posted by cetoole Thanks dsavitsk, I have seen that design before, I actually have a friend who has built it and likes it, but I have never heard it.

I just built one of these that I am now setting about to tweak. I was really surprised by how good it sounds. Actually, at first, it sounded terrible, but after about 2 hours of breaking-in it is really quite good.

 

[stadams]

I know you said that you wanted to get by "on the cheap" so to speak, but you should really take a look at The Pearl Phono. It's a nice design that you could sell to your friend after the fact.

Later,

 

[ericj]

I keep meaning to build Rod Elliott's RIAA phono stage:

http://sound.westhost.com/project06.htm

Two opamps, so i dunno whether that meets "on the cheap" or not. Depends which chips you've got or will buy, I guess.

 

[stadams]

Quote:

Originally Posted by ericj I keep meaning to build Rod Elliott's RIAA phono stage: http://sound.westhost.com/project06.htm Two opamps, so i dunno whether that meets "on the cheap" or not. Depends which chips you've got or will buy, I guess.

The design looks do-able and inexpensive although you will need a relatively quiet power supply in comparison to some more complex designs that include their own filtering and regulation. Also, the addition of a power supply equates to hidden cost unless you have one on the bench. However, it is still one of the cheaper alternatives available.

 

[ericj]

Agreed. I have a 36vct 40ma transformer and lm317lz/lm337lz set aside for it. Dual rail filtering w/ center tap is fiddly in small spaces but it can be done with good results.

 

[rickcr42]

For an OpAmp based solution the Analog Addicts "El Cheapo" using the OPA637 is about as good as it gets sound wise but only if built "honest" and with the parts specced.I have tried to get the same sound using the AD797 (and recently AD7797),the LT1028 and a couple of other ultra-low noise chips but this is the one that sounds most like actual music unless you are looking for that "ectched" solid state sound many seem to like.

Not real cheap to build but an option :

http://www.users.nac.net/markowitzgd/phonopre.html

couple of "build" threads

http://www.diyaudio.com/forums/showt...?threadid=9628

http://www.audioasylum.com/audio/twe...ges/48036.html

And no,I do not use one but only for the reason that I no longer use opamps in the signal path of my home based gear-only portable audio gear (until I can figure out how to get around it

)

 

[Garbz]

I should have my turntable by the weekend. If you can wait that long I'll give you a critical review.

Hell even if you can't wait i'll give you a critical review then

 

[cetoole]

Quote:

Originally Posted by Garbz I should have my turntable by the weekend. If you can wait that long I'll give you a critical review. Hell even if you can't wait i'll give you a critical review then

I can wait for reviews, this project is in no way a rush. Rick, are OPA637 clearly superior to OPA627 for that pre? I am wondering because I have a pair of OPA627 that could easily be used for the pre in pdip, but I have soldered both of my OPA637 to a browndog adapter, 2xSO8-pdip.

 

[rickcr42]

Quote:

I can wait for reviews, this project is in no way a rush. Rick, are OPA637 clearly superior to OPA627 for that pre? I am wondering because I have a pair of OPA627 that could easily be used for the pre in pdip, but I have soldered both of my OPA637 to a browndog adapter, 2xSO8-pdip.

The 637 is especially suited to high gain work such as phono stages and microphone preamps,the 627 way better for gains of X10 or less but in a pinch is usable in any circuit suited to an opamp.
You would be getting a different preamp however with the highs being a bit more closed in instead of the openess of the spec part.

 

[Garbz]

actually i find a night an day difference between the OPA637 / 627. It's just a real pain to get the OPA637 to behave. It should be very interesting to see if my values for RIAA curve keep it stable. But anyway the OPA637 is audibly much superior.

 

[cetoole]

Quote:

Originally Posted by rickcr42 The 637 is especially suited to high gain work such as phono stages and microphone preamps,the 627 way better for gains of X10 or less but in a pinch is usable in any circuit suited to an opamp. You would be getting a different preamp however with the highs being a bit more closed in instead of the openess of the spec part.

Cool, I will order me up a pair of these then.