|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
207.237.13.151
Hey guysIs it possible to use the tubed 351 preamp with another transport assuming you could tap the outputs off of the tape heads? Like an Otari?
Thanks!!
Follow Ups:
one for low impedance heads for their multi track Model 300s and one for high impedance heads for full track and 2 track. When multi track came around they couldn't cram much wire on the coil forms in the head so those machines have imput transformers at the input of the play preamp and are designed for low impedance heads. You'd have to find out whether or not your preamp has an input transformer for your play preamp. Ray Hughes
"I take you as you are
And make of you what I will,
Skunk-bear, carcajou, bloodthirsty
Non-survivor.
Lord, let me die but not die out." THE LAST WOLVERINE by James Dickey
Thanks everyone! I actually have a Bottlehead tape preamp (thanks Doc B.!) on its way to me soon....but am still looking for an RS-1500/1520 for transport duty.The Ampex idea was really just a curiosity. It seems like the 351 has received a ton of press..but I've never heard one - just would really like to :)
I'm getting very close! One tape head preamp is complete, two are at 95% complete, and two are at 90%. Other business has been competing for my time, but I should have them all done by the end of the week. BTW for anyone interested I updated the Seduction tape head project page with resistor and capacitor values for an IEC style EQ for the Sed. So now there's values published for NAB, IEC and Nagramaster.
NT
I've seen a few 351 electronics on ebay. They ain't cheap! And the rebuilding process is pretty involved. See the rebuild project of this very rig over on recordist.com.. Go to Ampex virtual museum> Repair, maintenance> John Hughes' 351 restoration. Very cool pic's and info! I think you might think about using something like an Ampex 440c transport if you did decide to go with the 351 electronics. With a set of heads to match, it might be easier than matching the impedances, and cabling. I'm sure Ray Hughs would know allot better than I. You out there Ray?
Would probably work OK at least for playback. Head impedances in transistor decks are lower. Playback Equalization would have to be tweaked - requiring a playback calibration tape (from MRL?) and maybe some adjustment of the input (head loading) resistor. Good luck in finding the Cannon plugs for the head connectors - might want to add RCA's on the back in parallel.
One could maybe get away without adjusting the input resistance going from a medium impedance head in a SS deck to the high impedance input of the 351 repro amp. Depending on the head used the output of the head might be a little on the low side for the gain structure of the preamp. Bear in mind that stock 351 repro electronics sound very nice, but they are usually a little noisy. All that said Charles is right, it should work. The reverse situation of running a high impedance head from a 351 into modern SS electronics would probably require adjustments.
Hi, Doc:I own an Ampex 351-2 which came out of our local "Berkeley Youth Radio" and it was in a rollaround cabinet with Innovonics electronics installed above. I assume that the Innovonics (sp?) electronics, though not as nice as the original preamplifiers which came with the deck, had been tailored for that transport.
Any comments, except the obvious one that Innovonics stuff sucks?
According to the manual, the Innovonics 376 can work with heads ranging from 200mH to 1H, with the optimum being 200mH.If it is equipped with the optional head transformer, and the strapping is changed accordingly, then it will work with heads ranging from 3mH to 6 mH, with 4mH being optimum.
Thanks, Paul!I have the data on the machine and I believe that everything is "as per".
This one turned up at the old location of Urban Ore in Berkeley many years ago.
If anybody is interested in acquiring this machine, it is available locally for very reasonable $$$
The transport is oddly marked "352-2" but to me, it is a 351-2.
Probably 7.5 / 15 ips only though. I cannot remember at the moment!
I purchased the deck essentially for the nice cabinet, which I wanted to insert my 3534-4 into one of these fine days!
Only Bodyslam would have the manual, and dig it out for you.
Hey Richard,I'm afraid I have no experience with the Inovonics preamps, but AFAIK they were indeed designed specifically for high impedance Ampex heads. The reason they were being retrofit in the 70's was supposedly about lower THD and the ability to handle really high output levels. Of course back then we all knew that SS circuitry was vastly superior to tubes. ;^)> I did find one reference to their sound being described as "aural sandpaper".
My only experience with aftermarket repro amps on a 351 is the Shafer tube preamps as used on Dave Dintenfass' Herniator MKIII at VSAC 2003. They sound very nice, but do suffer from the same bit of hum as the stock electronics.
Thanks, Doc!Sounds like the stories I have heard from others when it comes to those SS electronics as substitutes for the tubed originals.
I ran into Dave D. at AES two years ago, but not this year, though he may have been somewhere over in Moscone Center in SF.
I hope you were there and enjoyed the convention this year!
This post is made possible by the generous support of people like you and our sponsors: