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Hot Rodding the crap out of an A80vu 24tk... Recorders, Players & Tape Machines
Old 28th August 2007
  #1
Gear Head
 
JohnDavisNYC's Avatar
 

Hot Rodding the crap out of an A80vu 24tk...

i have a great old A80 that I use alot and love the sound of it... i am looking to figure out every possible way to upgrade these things... I am not sure exactly which revision this is... it has already had a varispeed box built for it, but i don't know how to tell if it is a mk2, 3, or 4.... it used to be at Water Music in NJ if anyone remember this machine there... has a big 'no smoking' sign on the front.

anyway, i am interested in compiling a list of all the mods that can be done to these, maybe switching the relays that control input/sync for punching to FET switches... any modern part substitutions in the channel amps that can improve performance... a John Stephens (RIP) style BIAS mod?

ideas please....

cheers,
john
Old 28th August 2007
  #2
Gear Nut
 
Goreski's Avatar
 

Why ??

You say you love the sound of your machine....
then why the hell are you trying to change something you love?
Love and stick with what you love...

surely you can screw-up anything, and change everything... but why?
I get asked all the time to mod or upgrade just about everything... Vintage Neve modules - I have a small Neve console in my shop right now in fact (but I'm not modding anything, just replacing and fixing things as needed), various tape recorders, Mic pre-amps...and so on
It's like buying a vintage Fender Telecaster, then changing the neck, the pick-ups.... you've got a guitar, but is isn't a Vintage Fender anymore.
Studer A80's sound great as they are... change what's before and after the recorder, not he recorder itself...
You can, however, help maintain the unit by changing various components before they fail... that makes sense.
The ONLY mod that makes sense is to change the IC socket connections over to a standard IC if you have the old A80 cards that take the old (obsolete) IC
Didn't mean to bite your head off... just to say, if it sounds GREAT... don't change a thing!
Goreski
Old 29th August 2007
  #3
Gear Head
 
JohnDavisNYC's Avatar
 

thanks for the reply...

as for not fixing what ain't broken, i totally agree.., but i am interested in mods that could address things like improving the punching, lowering the noisefloor, etc... i would like to take what i love about the machine and see what sort of mods are available... i am not looking to make it into an 827, but if there are things like caps that should be replaced with a better modern equivalent, i dunno... all that sort of stuff. just want to get some ideas. don't want to mess with much about the sound. i would say really, that quicker punching and lowering the noise floor would be the two main things i am interested in, but if people know of other mods, i am open to hear what they are.

cheers,
john
Old 29th August 2007
  #4
Gear Nut
 
Goreski's Avatar
 

A80 repairs for you to do...

John...there ARE things I recommend you do to your A80.... for stability and maintenance..


#1 thing is to replace the caps in each channel's power supply... these will go out soon. There are 2 large electrolytic caps in each power supply that you ned to replace ASAP... You will have to take out each electronics module then you'll have to take out each electronics power 'stablizer' module - take off the side plate and remove the power supply (aka stablizer) card. You want to replace these with higher values... I think they are 2500 uf 25 volt and you should replace them with the same physical size cap, but slightly higher values - maybe 2700 uf 50 volt 105 degree temperature caps. No higher than 4700 - and even that value may cause your fuses to pop with the inrush current. Please check that I'm right on the original value - my memory does not work perfectly all the time.

#2 is to tune it up as best you can and compare tracks to one another - see if you have noisy tracks, and so on, check erasure depth, listen for distortion (your ears are very good distortion sensors at 1 khz!). then fix those tracks as needed

next go to my website - Analog Rules!!! Pro-Audio Parts and Service and look at the secret tips button's bias tips. There's a ton of other info there, but not much specifically on the A80 - still well worth looking around!

Goreski</p>
Old 30th August 2007
  #5
Gear Head
 
JohnDavisNYC's Avatar
 

cool, thanks for that good first tip... will i need to modify anything in the power supplies in the bottom/back of the machine? or merely the individual channels? this is a great starting point... i imagine that just improving the power in each channel will make a big difference.

keep em coming, this is a great start.

cheers,
john
Old 30th August 2007
  #6
I was never able to do anything to an A-80 that made it sound great. It was always a better, but no cigar scenario. Once you use an A-800, you will lose all interest in the A-80. I remember the day that the first reels of Vanessa Williams' "The Right Stuff" was carted over to O'Henry studios for overdubs, the A-80 recorded tracks sounded like crap next to the tracks cut on O'Henry's MCI JH-24. This pissed the studio owner off so much the next day he ordered a JH-24 from Westlake and traded in the A-80. BTW, that record sounds pretty good.
The A-80 2 track is a completely different beast.

Jim Williams
Audio Upgrades
Old 30th August 2007
  #7
Lives for Jesus
 
stevep's Avatar
Thumbs up

Quote:
Originally Posted by Goreski View Post
next go to my website - Analog Rules!!! Pro-Audio Parts and Service and look at the secret tips button's bias tips. There's a ton of other info there, but not much specifically on the A80 - still well worth looking around!

Goreski</p>
Hi, nice website ! i found it a long time ago, its cool

Welcome to GS Analog Rules



.
Old 31st August 2007
  #8
Gear Head
 
JohnDavisNYC's Avatar
 

well, if people working on Vanessa Williams music think it sounds bad, then it is probably right up my alley... i can't think of a more pathetic example of something that 'sounds good'...

john
Old 31st August 2007
  #9
Gear Nut
 
Goreski's Avatar
 

John...

Ignore the folks who say 'this tape machine sounds bad, that one sounds great, and so on... the A80 is a FINE machine, and you can make GREAT sounding recordings. Go take my test... on which tape recorder sounds the best....

AnalogRules / BASE which Tape Recorder sounds the best?


do the individual cap replacements as I told you, clean the card connections, then do the tests as I've mentioned, and if necessary make repairs. Some of the great sounding records were done on A80's.... most of Europe was using A80s for years and years....

But make sure to go to my web site and look around - and try the 'secret biasing' tip!

Goreski
Old 31st August 2007
  #10
Gear Head
 
JohnDavisNYC's Avatar
 

thanks goreski... i will get on those caps soon... have to wait for some downtime in the calendar when i can go without the tape machine (or at least a few channels at a time) for long enough to get those caps changed out... i have done some more research, and it seems like it is a MKII... the record electronics are transformerless, but the repro and sync both have transformers (probably part of the squishy non-cheesy-80's-sesh sound i like)... it does not have the upgraded bias master oscillator (which maybe would make it a MKIV? i dunno... was reading through all of the service manual yesterday) nor the individual bias cards... the manual also stated that there is an option to add Dolby HX daughterboards to the bias cards... it has been a few years since i worked on an 827, but isn't that the case with the 827 that it has HX circuits built in? could be wrong... maybe it was just an option. i am guessing that next to none of these parts or upgrades are around unless i can find a parts machine or something.

if i replace the IC sockets like you say, is it easy to find a modern equivalent for the ICs themselves?

john
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