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Old 4th November 2002, 10:29 PM   #1
dorkus is offline dorkus  United States
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Default interesting little IC (AD797) preamp

i just received this interesting little preamp tonight from the editor of the audio magazine i write for:

http://www.raysamuelsaudio.com/new.html#ca2

haven't peeked inside yet so i'm not sure of the topology, but it uses two AD797's per channel. as for the sound, you would never guess what it is like. i don't mean that in a good or bad way, just that i was really shocked when i discovered that it used AD797s. i've never used them before myself but it sounds nothing like what i was expecting based on what people have told me about the IC.

anyone care to guess how this preamp sounds?

cheers,
dorkus
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Old 4th November 2002, 11:14 PM   #2
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Default anyone care to guess how this preamp sounds?

I'll bite.

It sounds like an op amp circuit with three terminal regulators and good but not particularly great parts (including the opamps).

Further more it sounds like you need to listen to some good stuff if this seems particularly impressive to you.

Sorry,
Fred

P.S." It has a tube like warmth and fullness without sacrificing details" according to the designer so I guess that must be it.

Hmmmmmmmm....tantalum caps, yummy.
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Old 4th November 2002, 11:32 PM   #3
dorkus is offline dorkus  United States
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Default Re: anyone care to guess how this preamp sounds?

Quote:
Originally posted by Fred Dieckmann

It sounds like an op amp circuit with three terminal regulators and good but not particularly great parts (including the opamps).
hmm, not really at all. sort of, but not really.

Quote:

Further more it sounds like you need to listen to some good stuff if this seems particularly impressive to you.
you didn't read my original post very carefully. i said " i don't mean that in a good or bad way..." so i made no judgement about sound quality.

i have heard "good stuff" and know what a good system (preamp, amp, or otherwise) sounds like, so there was really no need for the assumption (or condescention) on your part.

try again.
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Old 4th November 2002, 11:34 PM   #4
SY is offline SY  United States
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Dorkus, a perhaps-naive question- when you evaluated this unit, did you audibly compare the output to the input with the gain set to unity?
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Old 4th November 2002, 11:34 PM   #5
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Four OPs, Talema transformer, 3-pin-regs and 1000$ retail?
That doesn't sound like it could be loved by the DIY community.
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Old 5th November 2002, 12:16 AM   #6
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Quote:
Originally posted by HBarske
Talema transformer
Looks like an Amveco transformer, which digikey carries. You can buy the power supply seperately for $325

EDIT: I just realized that Talema and Amveco are the same company...

Digikey Part #: TE70053-ND $16.22 each

Still in no way makes it worth so much money...

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Old 5th November 2002, 01:36 AM   #7
SY is offline SY  United States
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It might be interesting to cost it out. For low-production stuff, normal retail should be about 5x bill-of-materials to stay in business. $200 in materials doesn't seem that outrageous of a guess, just from looking at the photos.
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Old 5th November 2002, 02:05 AM   #8
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Default but it sounds nothing like what i was expecting based on what people have told me abo

Come on drop it on us........ You obviously had an opinion about what it sounds like and you should have the conviction to stand behind what you hear. I have heard some op amps sould very good.

"but it sounds nothing like what i was expecting based on what people have told me about the IC."

Then tell us what you thought.


Respectfully,
Fred

P.S. This isn't the only one to take this approach.

http://www.vrilworks.com/MORRISON/audio_critic.htm
http://www.audioreview.com/PRD_118343_1591crx.aspx
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Old 5th November 2002, 02:23 AM   #9
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Default Fred - Tantalum Caps?

Quote:
Hmmmmmmmm....tantalum caps, yummy.
This may make me the most naive guy in the forum (and please don't jump down my throat if I am) but I've never tried listening to tantalums vs electrolytic caps. Are they that bad?

Cheers, BC
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Old 5th November 2002, 02:27 AM   #10
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Default ok, ok...

sorry for the teasing, especially to you Fred.

SY: haven't done a unity gain test. just got it tonight, so no A/B tests or anything yet, but i got a pretty good handle on the preamp's "signature." i can usually tell what a component sounds like within about 20 minutes of listening, excluding break-in effects of course.

HBarske & Brian: yeah i know it looks like a terrible value by DIY standards but what commercial product doesn't? SY's price break down sounds pretty accurate. after all, if Mr. Samuels is selling this for a living, the guy's gotta make a buck and feed himself. we've all seen far worse pricing in the "high-end" market, often for stuff that doesn't even sound all that great.

ok ok so what does it sound like. i guess if you read the manufacturer's page it sort of gave it away, duh... but yeah, it sounds like tubes! ok not EXACTLY like tubes but it's the closest thing i've had to tubes in my system since... well, a tube preamp. i was totally taken aback, as i was expecting thin analytical solid-state IC sound. it's big and bold, with lots of air and "space" around instruments. not totally accurate probably, but interesting and highly reminiscent of tubes. i'm actually not a tube guy at all (i find most tube gear highly distorted and colored) but i have to say this captures some of the positive attributes of their sound. that said, it still has some less endearing opamp traits (some grain and mushing together of sounds). i'm by no means saying this is the best preamp ever (it's not) but the sound is intriguing to say the least. i'll save the final value judgement for later after more extensive listening.

sorry to make such a fuss over an otherwise mundane piece, but i had heard the AD797 tends to sound cold and "bipolary" - am i wrong? i'm curious how the designer was able to voice the circuit like this, as it doesn't sound like any opamp circuit i've heard before.
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