DIY reel-to-reel ?

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#21
Hi Ingvar,
It would be nice if you could post that stuff if you can find it. I was also thinking along the lines of a Pass Ono adapted to NAB but then I'm not an engineer. Another guy,John Fosette up in Alaska bought my Studer A-80 and was going to design new electronics for it but he seems to have disappeared for the most part.

I am not to familiar with the Akai models but I remember they do have good ferrite heads in them. I'll ask around about a schematic.

Added:
Checked and found it available here. 82 pages plus schemtics.

http://www.stereomanuals.com/manuals/akai/akai.htm

Mark
 
#25
NAB replay amp

Hi Mark
Sorry for delay. We´ve been repainting our son´s room and the cat made an even bigger mess than usual, while at it we finished his speakers, came out good, and my Wife has gotten me started at tidying up the guestroom. Found NAB schematic, will clean up and mail, also found a nice National semiconductor NAB replay schematic based on fet input and op output, would be simple to change to all discrete. The design paper shows a perfect match to NAB correction. BTW if i get a visa for the cat would You be intersted in taking her on as an exchange student for a year or two?
 
#26
Sounds like you've been busy. Would your cat get along with two dogs😀 . I look forword to taking a look at those schematics. Thank for looking for them.
 

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#27
Searching my memory bank brings the following information up. Correct me if I'm wrong.

Proffesor Keith Johnson, owner and chief engineer of Reference Recordings designed his own tube electronics for tape recorders because he wanted the very best. He may have documentation available - or maybe not.

Let Google do the walking.
 
#30
I'm sure they're good BUT.... The very best tube tape preamp I've ever heard is an old Ampex MR70 which was among the last tube units Ampex made. The MR70 electronics has three bands of playback EQ adjustment per speed.

I once mastered a CD at Bob Katz's place in Orlando and he had a pair of these wonderful units which had been modified with higher grade coupling caps and other goodies. I had the lucky chance while there to do a direct A-B comparison to my Nagra Stereo a number of years back... The Technics RS-1500 with the MR70 electronics really trampled the poor little finely tuned Nagra!

Check out this link to Bobs web site! Bob is one of the very best mastering engineers around.

Mark

http://www.digido.com/portal/pmodule_id=11/pmdmode=fullscreen/pageadder_page_id=108/
 
#31
I found some MR70 schematics here:

http://recordist.com/ampex/apxschem.html

I remember that the original AG-350 RP amps had a very fat sound to them. I’ve heard that they are becoming something of an endangered species too. Seems that they are very popular modded as mic preamps.

I haven’t actually used the Manleylabs amps. I'm guessing that they are popular on the ATR 102 transport. 1/2 inch tape at 15 IPS... WOW!

I have used the ATR 102 transport but only with the solid state amps, like its video counterpart the VPR-3, not pinch roller.
 
#32
Yea, I'm sure the Manley's are very good at 2500.00 per channel. My impressions of the difference between the Nagra and the MR-70 was far more inner detail and more life like reproduction whilst the Nagra sounded somewhat lifeless and somewhat dry. The difference was VERY apparent. We ended up useing the RS1500 with MR-71 electronics to transfer to the editing system.

BTW...Thanks for the link to the Ampex schematics!!

Mark
 
#33
Which Nagra was it, a IV s or a T? Great machines. I think I would describe them as 'clinical' compared to a tube machine.

I like the name Sampex. Reminds me of an AG 350 overhaul I read about a while back, the "Magansaurus".

Of course I’m not suggesting that we all run out and buy $2.5k mastering amps...
I guess I dropped it in thinking in the musicians spirit of Beggars and Thieves There are some great ideas in there for someone looking to build themselves a machine. A box full of surplus verier dials could turn a good effort into something with an uncommon level of precision and usability.
 
#34
I would first buy an old Ampex studio deck and study the heck out of it. I'm not a tape recording expert, but do have one of their old CA 1975 dual capstan decks and sure love it. I also used to maintain Ampex insrumemtation FM recorders (0-100 KHz) and kept in contact with Ampex.

That is when I learned about the "captive tape" concept, where the output capstan takes up the tape faster than the input capstan supplies it, thereby slightly stretching the tape and isolating it from reel speed influences..

Mort Caldwell
Got to again set up my completely DIY audio stuff soon.. My new wife kicked it out of the living room in 2000. Oh well, I'm down here in a very nice acoustic basement.. sure!
 
#35
hi, i too have been thinking about building a multitrack recorder, i have a teac x-10r and a 2000r, i wanted to try a 24 track using a 2" head, using the control electronics from the teac and modifying the spools/mechanism etc, i was looking at a chip that caters for recordand playback in one, how about the ba3420al? if i cant get hold of a 24 track head i was going to use 12 normal tape heads (they would have to be staggered in some order), i was also considering a lower track version using video tapes, and using an old video recorder, not sure how many tracks i would get on it though, any ideas on a suitable chip that i could use for the record and playback, im not too bothered about sound quality (within reason) at the moment i just want to get the thing working, if it works well i can always replace the audio side with a high quality at a later date. joe
 
#36
joey,

Don't even think about this. First, no Teac 1/4" machine has the
oomph to move 2" tape. It's only 8X the mass and 64x the
inertia.

There's no way you will be able to stagger normal 1/4" heads
across the tape; the shield will prevent the actual head from
contacting the tape. And how are you going to equally stagger
R and P head pairs.

Do you know the price of a set of 2" 24trk heads?
 
#38
hi, ive tried to find the prices of 24track heads on the net but to no evail, i think youre right about the torque required to move a 2" tape, i think the video cassette version will be better, if i use all the controls and decks out of the video and just remove the drum and replace it with tape heads, i thought of using normal cassette heads, am i right in thinking that these are record/playback heads in one and also contain the erase head? if so it would be easy to stagger them (obviously i wouldnt be able to use the tapes on any other machine), im sure i should be able to get at least 16 tracks on a video cassette tape and if i speed it up aswell (after all i dont think i will need 4 hours on recording time), a normal cassette has 4 tracks on it (A, l+r and B l+r) so i should be able to put 16 or more tracks, any suggestions as to whether this will work, as i said earlier at the moment im not after 2" tape quality just decent qualityto see if it will work. joe
 
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