interesting little IC (AD797) preamp

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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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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.
 
Re: anyone care to guess how this preamp sounds?

Fred Dieckmann said:

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.


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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HBarske said:
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...

--
Brian
 

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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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ok, ok...

sorry for the teasing, especially to you Fred. :p

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... :rolleyes: 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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Thanks for clarifying that...

I did no such thing..... some people like tantalums for audio and some do not. I am not going to decide for anyone. I have heard passionate proponents and equally biased opponents. The same goes with silver Mica caps.

I feel strongly both ways,
Fred

P.S. Sorry.... its those damned elections. Like the Devo song says:
Freedom from Choice.
 
Re: sounds like tubes

Fred Dieckmann said:
Hmmmmmmmmm.......

yah. incidentally, that tube preamp shown, the RS-1, is an excellent preamp apparently, one of the better ones my editor has heard - and he's heard a LOT.

i'll open up the one i have soon to see what it's like inside. i see one mention of tantalum caps on that web page, but with the headphone amp, not this preamp. i can't see where he's using them though.
 
hmm...

i just did a quick comparison test between this new preamp and my current homebrew one, a simple 2 JFET Boberly buffer (a la Harry Haller) with shunt attenuator - not the nicest implementation (lots of cheapo parts, was a weekend project) but still a faily good-sounding unit. the weirdest thing... i was comparing the 2nd mov't of Rimsky-Korsakov Scherezade (CSO/Reiner Living Stereo CD), and when i switched from the Ray Samuels to my own homebrew, it sounded like the oboe solo was being played faster. huh??? i kid you not, my girlfriend who was casually listening (she's an oboist, played the solo herself in university orchestra) swore i sped up the CD or something. going back to the Ray Samuels, it seemed to get the free pacing of the solo better, with more dynamic nuance and phrasing inflections... kinda like good tube gear eh? on the other hand the tonal balance is not as tubey as i initially suspected - it's actually pretty neutral and close to my JFET buffer, but a little more bloom in the lower midrange and bass and *maybe* slightly more pronounced upper midrange... again, sort of like tubes. interesting...
 
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

After reading this entire thread, I have to ask -- what exactly is "cold and bipolary"? If the goal of an ideal amplifier is to produce a sonically accurate copy of the source material, then it's hard to beat something like an AD797.

not totally accurate probably, but interesting and highly reminiscent of tubes

If you believe the spec sheets, the THD vs. frequency is at .0001% upto about 50KHz, where it climbs to a whopping .00013% -- even at 100KHz (which is getting close to the bandwidth of a lot of practical audio amps), it's only .0003%

I would hope that this sounds nothing like a tube amplifier, as it'd be missing all of the distortion (relatively speaking) that tubes typically introduce.

Assuming that the designer took some reasonable measure of care in the design and layout (and discounting all other components in the system), the audio should sound about as close to the original recording as you're reasonably going to get right now.

FWIW, Madrigal uses the AD797 in the Mark Levinson 38 series preamps (and possibly others).
 
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the audio should sound about as close to the original recording as you're reasonably

Boy that's a relief.............:spin:

First the power supply design by numbers and now this......

Thiis my lucky day. Now I can take up bird watching since all the frontiers in audio design have been conquered.:smash:

Free at last,
Fred
 
"For low-production stuff, normal retail should be about 5x bill-of-materials to stay in business."

Try 10x if you want to be sucessful.

If you are buying parts and building stuff in quantities that small that you are only charging 5X, you won't be able to compete for very long.

Some of us have already tried that.

Jocko
 
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