[Magic Robert]

Possible winner for the most off-the-wall question this year.

I acquired the line driver listed in the title, sorta as a gift (a guy I bought some used gear from included it in the shipment - with no explanation). Popped the case, checked it and powered it up - all is well.

Can anyone tell me any specs on this unit?  It has one input and two outputs; its purpose is the same as every other line driver out there. It appears to be late '90's vintage.

The only information I have is from the label "300V/microS Hybrid Buffered Circuits" "Serial number 031301" "designed by Aado Perandi for AUDIO BY VAN ALSTINE , INC.

No information on it even in the Internet Wayback Machine.

I was just curious regarding input/output impedance and voltage input/output, particularly input voltage recommended max and mins.

Any information is greatly appreciated.

The only applications I can see for it is driving long line-level cables, increasing signal level into a tape loop, or front-ending a commercial amp for a residential subwoofer setup that is being driven by a too low sub output from an AVR for the commercial amp.

Hoping for at least one or two comments. I never knew Frank built this specific piece of gear. All I have to check it is a Fluke DVOM, so I am at a loss.

Thanks.

[dB Cooper]

I have the (I think) preceding version and your analysis of the function is spot on. I seem to remember 1MΩ output impedance but Frank will know.

Hate to say it, but I don't think this is even in the running for the most off-the-wall question this year 

[avahifi]

The serial says this was built in 2001.

Can you send me sharp photos of the internal circuit boards and the internal connections to the RCA jacks.

Does it have a volume control.

Send the info to frank@avahifi.com.

Depending upon the wiring it could either be a tape buffer or possibly a phase inverter bridge circuit.

Frank

[dB Cooper]

Or post them here so we can all nerd out...

[Magic Robert]

I am going to get pics to Frank later this week. Based on the previous post, is it ok to post the pics on this forum? I am an idiot reading circuit layouts. It looks like a buffered fixed output "pre-amp"; in other words add a potentiometer and you have a pre-amp. So, someone let me know that it's ok to post circuit board porn , and if Frank okays it, we can have a tiny nerd-fest. I am already laughing.

[Magic Robert]

Oh, and a huge shout out to Frank for offering to take the time to look at it.

[Magic Robert]

Finally got images to Frank today. What a guy. I never expected him to volunteer to help. As I said, what a guy.

[dB Cooper]

AVA made a seies of modular kits for years they called 'Versa-Kits'. They all used the same board set but could be configured as a line buffer (which is what it sounds like you've got), stereo line preamp, RIAA phono preamp, or phase splitter (for bridging stereo amps). The instructions should still be available as part of Frank's 'Audio Basics' back issue set in case you wanted to, say, turn your buffer into a stereo preamp. There were two iterations of this concept IIRC, one with everything on one board and one with the power supply section on its own board. Should still provide very good sound for whatever the configured device type is.

[Magic Robert]

Thanks for the reply. Where can I find the information you are referring to? Is it on-line? If so, I missed it. I believe this little guy predates (or postdates) what you are referring to. In any case, this one is factory built. If i find out it is okay, I will post pics if anyone is interested. What I have looks like a fixed gain pre-amp (=line-driver) on one small board. I will update Frank's findings after he looks at the pics.

I ain't that good at reading circuit boards, but I can see it is buffered, and does provide as fixed gain.

Audiocircle has been good to me. Now, my wallet? As my late wife would say, you wouldn't believe how much money I saved (cue maniacal laughter here).

[jmc207]

Thanks for the reply. Where can I find the information you are referring to? Is it on-line? If so, I missed it. I believe this little guy predates (or postdates) what you are referring to. In any case, this one is factory built. If i find out it is okay, I will post pics if anyone is interested. What I have looks like a fixed gain pre-amp (=line-driver) on one small board. I will update Frank's findings after he looks at the pics.

I ain't that good at reading circuit boards, but I can see it is buffered, and does provide as fixed gain.

Audiocircle has been good to me. Now, my wallet? As my late wife would say, you wouldn't believe how much money I saved (cue maniacal laughter here).

Audio Basics August, 1992 has info on building an Omega II Line Preamp and it shows the circuit board. If yours is a hybrid line driver the board may look somewhat different or have a different opamp. I believe there are other newsletters with other Versa-Kit uses such as a line driver.

You can find the Zip file of all of the Audio Basics newsletters here:  https://avahifi.com/pages/audio-basics-newsletters

Neat little devices. I still have one of the Omega II line preamps written about in that Aug. 1992 newsletter.

[dB Cooper]

van alstine site > resources> Audio Basics newsletters (it's one big zip file)

You'll have to do some spelunking to find them, but search those for 'Versa-Kit'. I think you have the later version.

A lot of the specific equipment discussed is obsolete, but there's also a lot of still-useful info in there about sound reproduction in general.

[charmerci]

If you search backward or scroll quickly, at some point there is an up-to-that date index in the newsletter.

[dB Cooper]

Acrobat Reader (PC) or Preview (Mac) shoul be able to find it. The one you're looking for (on 2 boards) spans a couple issues of the newsletter. Nice 'freebie' to get with your purchase.

[avahifi]

This unit is a unity gain buffer (no voltage gain) built on the one board configuration with all power supply parts, including transformer, sharing a common board with the audio circuits.

I will see if I can find better data when I am at my business computer later today.

I checked this out.  The PC-392 board used for the Audio Basics project was an early version of the design using an opamp only for gain (no buffer stage).

The newer board in the Omega III buffer we are talking about has an opamp followed by a current buffer.  I will need to know the product IC number (PC-xxx) of this board to research it further.

Frank

[Magic Robert]

Frank and I (I find it weird calling him Frank with as much influence as he has had on my "audiophool" journey) have a dialogue going. I am going to get some more ID info on this 2nd gen board by physical examination. Poco a poco, with Frank's able assistance!

[Magic Robert]

Frank -

The board is a PC-195. I have a pic if that is of help.

Thanks again for your assistance.

- Robert

[Magic Robert]

Frank, thanks for all your help. 

[avahifi]

I found a stuffing guide of the PC-195 board for its standard 20 dB gain line preamp function and sent this on to Magic.  Hope this helps.

Frsnk