Studer A80 RC

SeleniumFalcon

A few months ago I was able to buy a Studer A80 tape deck from Steve Smith and Dan Labrie of Myriad Magnetics located in south Philadelphia. I've just about completed the cleaning and refurbishing of the deck and thought I'd take a few photos while it was apart.




This photo shows the underside of the deck, one of the last things I'm doing is replacing the capstan motor with a NOS one that I bought. It only requires removing four bolts and unplugging a connector to completely remove the motor.

Clipdat

Congrats on the acquisition!

SeleniumFalcon

This is a photo of the original motor after being removed:



It's actually just a larger version of the capstan motors found in the Revox A77 and PR99 decks.

SeleniumFalcon

Here's a photo of the area where the capstan motor is mounted, the lower left is the compartment where all the record and playback electronics are connected. To the right is the area where all of the transport logic electronics are housed. Both sections fold down to give better access to some of the mechanical areas.

SeleniumFalcon

This photo shows the rear of the transport logic section and all of the wire wrap connections.

SeleniumFalcon

This photo shows the motor phase capacitors which I replaced.

SeleniumFalcon

This photo shows the massive cast aluminum chassis assembly found on the front of the deck. For the lowest wow and flutter all of the transport parts have to be held as rigidly as possible.



The two brass assemblies are part of the transport's dashpot tension control. The two lower round assemblies are the supply and take-up tables. All of these parts were cleaned and polished to look as new as possible.

pitdogg2

I'll give you $40 for it when you're done 😁

JayCee

SeleniumFalcon wrote: »

This photo shows the rear of the transport logic section and all of the wire wrap connections.

That's pretty incredible and, I'd imagine, a tedious/dexterous nightmare to redo.

invalid

Nice machine!

Jetmaker737

Next level skills!

Joey_V

Impressive

txcoastal1

pitdogg2 wrote: »

I'll give you $4000.00 for it when you're done 😁

Fixed your typo Ivan

pitdogg2

Wait a cotton pickin minute!!! When did we get married??

SeleniumFalcon

I've installed the new motor.

SeleniumFalcon

There's a company in Switzerland that is a source for Studer parts, one of the things they've developed is a re-build kit for the plastic covers for the transport controls. I also sourced some replacement lamps for these controls but noticed that the "stop" bulb was not as bright as the others. I looked at the service manual and saw the dropping resistors and measured them and the "stop" resistor was off the value. Plus for some reason one of the resistors was missing, so I replaced all of them.

SeleniumFalcon

You can see the resistors in the upper left of the photo. I can return the deck to its normal operating position. I need to put a single drop of oil in the top of the capstan motor before turning everything on.

pitdogg2

That sure looks like a clean machine Ken.

F1nut

Ken, was anyone else at 5601 Metro into R2R?

You may have told me before, but I don't recall, where did you learn how to repair them?

SeleniumFalcon

Mark Suskind was a tape enthusiast, he had a Revox A77 that had taken a tumble off a shelf. I got it back in shape by swapping out some chassis parts with a second deck he had. I think I've always liked taking things apart and trying to put them back together, hopefully working. This A80 is the easiest one I've ever worked on, a real dream. It must have been designed by somebody who has to repair them for a living.

F1nut

Ah, I didn't know Mark was. I hope he's doing well.

I've always liked figuring out how something works and just fixing stuff in general, but I've never wanted to play around with one of those.

Joey_V

@SeleniumFalcon
Can you tell me why is it that some R2R are large stand up models and others like the Metaxas is small? Are there duplicitous parts for simple playback that is not needed?

SeleniumFalcon

Good question @Joey_V . I believe it has to do with the applications that the original tape deck were designed to fulfill. Tape decks such as the Stellavox (the Metaxas' grandfather) and the Nagra were designed as field recorders. They were used by movie studios and radio stations to record on location. They had to be small, light weight, modular, in a Stellavox much of the record and playback EQ is encapsulated in the head locks so plugging and unplugging a head assembly doesn't require any alignment issues. All of the internal circuitry are in small sealed modules that can be quickly field changed if there's a problem.
On the other hand tape recorders such as the Studer were designed for recording studios and radio stations primarily. They were often used to take a tape made elsewhere and edit it for final production. As a result they have very advanced tape transport systems that aid in editing tapes. This type of transport carefully balances the torque exerted by the supply and take up reel motors to get just the right amount of tension on the tape. This means the tape flows extremely smoothly across the surface of the heads without any changes from beginning to end. This kind of transport isn't needed on a field recorder since its job is to simply make a continuously copy of whatever is being fed to the microphones. Somewhere else will take the tape and manipulate further up the chain.
So what does this mean for the audiophile? There are two types of available tapes for the serious tape enthusiast. One is the collection of audiophile quality 2 track tapes from RCA, London (Decca), Mercury and Everest. They are at least 50 years old and rare and expensive. They need very special care especially in rewinding and fast forwarding (many enthusiasts simply don't rewind or fast forward but flip a finished tape over and let it play in the opposite direction). Machines such as the Studer have edit functions that control how fast the tape is shuttled back and forth, originally designed to access certain parts of the tape but now provide super careful tape handling.
Another issue for these older tapes is the guide systems used by manufacturers to carefully position the tape across the heads. Some companies use several metal guides such as this:



To hold the tape firmly from where it enters the head block and exits, keeping it following the correct paths. However, the most delicate part of these older tapes is the edges. Where the layers of oxide are bound to the plastic ribbon needs to be handled carefully to not damage the coating. Other tape transports that have accurate tape tensioning can eliminate the need for these metal guides:

SeleniumFalcon

The second type of tape enthusiast, rather than collecting vintage tapes, buys master tape copies supplied by companies such as The Tape Project, Chasing the Dragon, Horch House, Proprius and many others. These are tapes made on new stock rather than old and are not as delicate. The goal here is to move the tape as perfectly as possible across the heads with no audible changes in speed. Some tapes are recorded in NAB format and others are recorded in IEC format, all are 2 track and play at 15 inches per second. Low frequency changes in speed is called wow, medium frequency changes in speed is called flutter and high frequency changes in speed is called scrape flutter. Scrape flutter is thought to be the most audible form of speed changes since it adds an audible grunge to the way high frequencies sound. You know when guitar effects guys design a "stomp box" for this type of distortion it really has to be audible:



This higher frequency (centered around 10kHz) is caused by the tape sticking very slightly to the head's surface, then releasing, then sticking again and so on. This is similar to rubbing your finger on a smooth surface with just the right pressure to cause a high frequency sound to happen. The tape stretches very slightly causing minute shifts in time. It is very similar to the differences heard between moving coil cartridges (which don't produce time distortion) and moving iron cartridges (which do ). The solution to this type of distortion is to use precision rolling bearings called scrape flutter bearings and eliminating unsupported lengths of tape:



These are carefully placed to support the tape, breaking up unsupported length of tape and having extremely low friction. Think of these bearings as important as the bearings in an audiophile tonearm. It is believed that only tape transports that were designed with carefully controlled tape tension, ultra precise capstan motors, extremely massive frames with rigid positioning of all tape handling areas be low in this high frequency distortion. Ampex believed the effects of scrape flutter were not audible, recent rethinking believe differently.

SeleniumFalcon

The other thing about audiophiles, in general, is that they are never happy. This applies to tape enthusiasts as well, we are never happy. The Achilles heel of tape listening is the electronics used to shape the final sound once it leaves the playback heads. The late model Studers and Ampexes relied on circuitry concepts and parts that were available in the early '70's. Many models (Studer A820, for example) place IC opamps right in the head blocks to eliminate using noise inducing cabling running to the circuit boards. All of the circuits used by every deck manufacturer are not the best examples of what can be produced. Imagine how vinyl playback has benefited from research and development for the past 50 years. The same for tape playback (and recording, which isn't much concern for most enthusiasts). The solution is to have a deck because of its tape handling and low distortion capabilities and feed this signal to an external audiophile quality tape playback preamp.
I hope this is helpful.

For example:

Joey_V

Would a Metaxas going into my arc linestage be a good clean way of getting great sound?

SeleniumFalcon

I believe the Metaxas deck is a great choice. For many years the Stellavox SP7 was the tape deck of choice for audiophiles. The designer, Georges Quellet, made the best sounding deck you could buy. Mr. Metaxas has taken that design and perfected it, using really expensive DC motors and advanced metal machining and keeping the special circuitry designs. I love my SP7 and can only imagine what the Metaxas must be like.
Who knows, add a couple of good microphones and you could be making great recordings of your kids doing their first piano/violin concerts!

Joey_V

Interesting….

Jetmaker737

Excellent stuff, Ken. Appreciate the info, super interesting. Some of this I've never heard.

I am one of those guys who plays my old tapes all the way through. After a couple of breakages after a FFW stop this is what I do. Of course the deck might just need some new brake felt. A job I haven't gotten around to tackling but seems pretty straight-forward from what I've read on Tapeheads.net. I've only opened up my deck to apply oil to the motors yearly and once to replace the counter belt. Yeah, I'm a total noob.

F1nut

Ken, I hope you don't mind. I saw this eye candy today, love the wood accents.

SeleniumFalcon

This might be a bit over the top for you, Jesse: