Studio Projects 8 Channel Pre?

  • Thread starter Thread starter OneRoomStudios
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Alan,

Does the VTB-1 use Burr Brown? Not meaning to take this thread off topic, but just curious. Kinda sounded that way in your post, and I wanted to see if I was misinterpreting. :) Didn't think the VTB-1 did.
 
No warble... here's a quote from the Studio Projects web page about the VTB-1.

Circuit Topology:
Discreet, current-source fed, paralleled-transistor balanced input stage feeding a bipolar opamp balanced-unbalanced converter. Dual feedback design for low distortion performance. 2-Stage design for increased performance; transistor stage provides up to 45dB gain, 2nd stage contributes up to 15dB gain.
 
alanhyatt said:
You can't really distinguish between the Burr Browns, and I am sure Sytek has not made any custom Burr Brown, but I am happy to be corrected on that...
Click to expand...

You're correct, Sytek was buying a particular BB chip a couple of years ago that had a darker sound. But the chip is no longer produced, and now there is no real noticeable differences when paying extra for the 2 BB channels.

War
 
As far as the opamps you guys are discussing (OPA) . . . who really even knows or cares? I'm sure that's more a question for Mike Stoica, concerning anyond who owns a Sytek.

What we're talking about is the INA-163 versus the INA-217.

I realize both of you guys have a vested interest in the 217 due to the products you're rep'ing. But in the interest of fairness, I think people need to know that there are inherent differences in the two chips. They're not pin-compatible, they're not going to sound exactly the same . . . and there seem to be those who prefer one over the other for reasons I don't know enough about to explain.

Maybe it's a carry-over from all the tube hype. a 12AX7 is different from a 12AT7 or an EL whatever . . . some tubes are not compatible or interchangeable, and serve different purposes, and/or they have different effects on the sound.
 
So Chessrock, do you think there would be a sound difference between an INA217AIDWT and an INA217AIP? They're not pin-compatible either (the AIP has 8 pins, the AIDWT has 16). They are both INA217's though. I would imagine they sound pretty damn similar despite the fact that they aren't pin-compatible, so I don't know if that's really a way to judge sound differences.

Also, I doubt the sound difference between op-amps is anywhere near as drastic as the difference between tubes, but I could be wrong.
 
OneRoomStudios said:
Also, I doubt the sound difference between op-amps is anywhere near as drastic as the difference between tubes, but I could be wrong.
Click to expand...


I would tend to agree with you. Still, I have been privy to more than a few discussions with people who swear that there is a noticeable difference between one chip and another.

Linear Technologies used to be the big guy on the block in terms of audio-related silicon. They used to make two different chips : The SSM-2015 and the SSM-2017. And apparently, there was so much of a noticeable difference between the two, that some pretty heavyweight audio guys basically deemed the 2017 as having unacceptable amounts of HF distortion, etc. (resulting in a brittle sound) and would even go so far as to recommend against any mic pre built around one -- meanwhile singing the praises of the 2015.

The 2017, by the way, happened to be the predecessor of the INA-217 we're now talking about.

At the same time, Burr-brown's INA-103 was turning a lot of heads and making quite a splash. The audio geeks gave it their approval. Grace Design were using it in their stuff . . . M-audio was using it in the dmp2, which got quite a bit of accolades at the time amongst the project studio crowd, and a few nice consoles, I believe started using it.

That chip, by the way, was the predecessor to the INA-163.

What does it all mean? I have no idea. Again, it could all just be a lot of geeks flipping out over nothing. Or maybe they know something the average joe doesn't ? Either way, it's above my head, but I think some of these discussions are at least worth noting . . . if not looking in to a bit more.
 
chess , not wishing to be awkward,so dont jump on me, but actually analog devices were the manufacturer of the ssm and 2017 op amps (analog.com).
linear techs low noise op amps are for example LT1115 and LT1028 as examples. thatcorp.com also have some new chips plus an interesting mic pre schematic on their site that looks nice fyi.
various vendors make high quality versions of op37 and 27 op amps which personally i prefer. one of the best op amps ive tried for audio , just personal preference is the maxim variant called the max 437. its TOUGH !
 
My bad. I wonder if THAT is ever going to come out with that mic pre chip. They're still advertising it on their site -- and have been for the last four years. :D
 
ive been wondering the same as you about THAT.
didnt know it wasnt out yet.
actually a nice design to try is analog mat transistors in front of a op37
type op amp. been fooling around with this for awhile for laughs.
the analog.com mat transistor is the lowest noise ive come across
in transistors. just an idea if anyone is into building stuff.
 
Just wanted to point out that the INA217 is not really the successor to the SSM2017. The INA was designed as a drop in replacement for the SSM, yes, but it's designed by different people and pobably has a different internal structure.
The SSM2017 was very popular for a while, but for some reason Analog Devices discontinued it. That's when Burr Brown came in and said, hey, there's a market! Let's make a replacement chip. As it happend, the replacement sounded better than the original.
THAT also saw the demand for a SSM2017 replacement, but they never came up with a finished product. I suspect they lost interest, seeing that BB dominates that market. Analog Devices now has a successor chip, the SSM2019, but I doubt they sell a lot of those.

I also wanted to point out for those who wonder what the hell we're talking about that those chips mentioned are not plain operational amplifiers. Opamps are multi purpose amplification devices.
SSM 2015/2017/2019 and INA 103/163/217 are so called "instrumentation amplifiers" (a particular configuration of three opamps). Those particular chips are specifically made for microphone amplification. And that's probably why they perform so well in that application.

What Sytek does seems to be something different. From what I read on the website, it seems they use regular opamps, either in the input stage or behind a discrete transistor input stage - like in the VTB-1 or the design Manning1 is working on.
 
Thanks for clearing things up for us, Rossi ! We appreciate the info.
 
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