Ampex 351-2 restoration project

mhardy6647

I dunno -- varnish, cloth, varnished cloth :-P rubber and PVC plastic were all used; other things, too, I wouldn't wonder. In some cases, no insulation at all in the early days of radio.

Wire wrap wire is Kynar insulated (and don't ask me what Kynar is -- some sort of synthetic polymer).

mhardy6647

a feeble attempt to keep this thread visible in "recent posts" :-)

Let's see what I can find in the vaults...

Scan0010 by Mark Hardy, on Flickr

oh, oh, this, too -- speaking of the 1970s Philips consumer decks, which Gordon Miller sold -- but apparently didn't put in their catalog on the reel to reel page.

philbro1 (1) by Mark Hardy, on Flickr philbro2 (1) by Mark Hardy, on Flickr

small%20Scotch%20201 by Mark Hardy, on Flickr

mhardy6647

Nightfall

Wait. Philips ad. Our speakers are priced from less than $120 each to over $1,000. There was a $2,000 pair of Philips speakers? What? I want to see them.

mhardy6647

It was probably the active, triamped ones -- that's another thread, though ;- )

mhardy6647

small%20maxell%20later%20UD3590 by Mark Hardy, on Flickr

[Deleted User]

Eureka! It's alive!
First time for actual tape transport operation and everything works! I've cleaned and replaced capacitors in the transport control box, replaced the main cables and cleaned the three relays and motor tension adjust resistors. I've cleaned and replaced the transport control buttons (went with the older brass buttons) had the rubber pinch roller replaced and connected the AC power and it works. Motors spin, pinch roller arm activates, safety arm functions, it rewinds and fast forwards.
Now I have to calibrate the supply and take up tension, I have a digital bicycle scale on order. Then I have to begin on the head-stack.

mhardy6647

wow. definitely a labor of love.

[Deleted User]

Here are a few more photos that might be interesting. The first shows one of the vacuum tube record and playback electronics sections. This one has the main AC connections for the transport.

[Deleted User]

This is another photo of the same component, but from a different angle.

[Deleted User]

This one shows the front of the transport, only the top half is the Ampex. You can see the safety on/off switch on the right. If the tape breaks during play or rewind or fast forward this arm comes down and stops the transport. The left side is a really well made tension flywheel, very low friction and works to smooth out tape motion and provide precise wrapping of the tape over the heads. The area in the middle is where the head stack will be mounted.

[Deleted User]

Over the years I've accumulated lots of duplicate parts, now the supply has really dried up. This shows the two head stacks I have collected. One is NOS with high performance record and playback heads. Ampex built their own cables to run from the heads to the electronics assemblies. They are heavily shielded and ultra low capacitance, probably made a good general audio cable.

[Deleted User]

Wow, I can't believe it's been a year since I've updated this thread. Progress has been good and I'm seeing a small, fuzzy light at the end of the tunnel. The 351 transport has been working like a charm, it has become the smoothest operating and quietest transport I have. A pleasure to use. The signal from the heads are being amplified by the Dehavilland for listening while I finish the two Ampex playback amps.
I've completed all six of the circuit boards, completely removed and replaced every component and polished the metal bits (photos to follow). I had the two chassis stripped and powder coated and the printing etched and filled for the back panels (photos to follow). The two AC transformers were taken apart and the bell housings stripped and powder coated, new fish paper installed and the transformer laminations painted.
I've kind of created a game with myself, trying to find as many NOS replacement parts for the Amphenol connections on the rear panel. I keep researching the old part numbers found on the grimy part and see if there are any sources for them. I'm kind of hitting bottom on the selenium rectifier and trim potentiometers, but I keep searching.

pitdogg2

Man Ken that's some serious restoration!! Definitely some large man hours in this piece.

[Deleted User]

As promised here are some photos of the power supply, record and playback circuit boards for the 351.
In order to thoroughly clean the circuit boards I had to remove everything from the boards and then put them in an ultrasonic cleaner which did a great job. It got rid of decades of stains and grime. I replaced each of the resistors and capacitors with components that I felt would maintain the original sound character but eliminate some of the possible grain and noise. I've kept all of the removed parts so I could go back and check values if necessary. I tried to remove as much of the old tin-heavy solder from the signal traces and reapplied new solder. I was able to find NOS of the trim capacitors and replaced all the jumpers with Wonder Wire and Teflon sleeves. New tube sockets were needed.
I have a third amplifier that I've kept stock so I can compare everything when I put it all back together.

[Deleted User]

Thanks, pitdogg2!

mhardy6647

so pretty... nice photos, too.

[Deleted User]

Thanks, Mark, I'll post some more when I get the roll developed (just kidding).

vmaxer

KennethSwauger wrote: »

Thanks, Mark, I'll post some more when I get the roll developed (just kidding).

At least use this:



https://m.youtube.com/watch?v=qrRRhoS3KFk

[Deleted User]

"It gives you such nice bright colors!"

vmaxer

I probably have some around here somewhere??

mhardy6647

We still pull out a roll o' film here now & again.

shelfies1 120315 by Mark Hardy, on Flickr

actual film (good ol' TX-135)

34210033 by Mark Hardy, on Flickr

[Deleted User]

I love my Nikon film camera and still have some film in the fridge.

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vmaxer

Me too, not sure it's still good. I have an old Canon ftb and a Nikon F5.

mhardy6647

KennethSwauger wrote: »

I love my Nikon film camera and still have some film in the fridge.

We're a Nikon shop here, too (mostly) -- my son, who lives in VA, is the serious photographer, though. Some of the cameras and lenses at my house are, in fact, his (but that's another story altogether).

http://icouldbeahero.blogspot.com



(from his college days -- note the Frank Zappa tee-shirt subject matter, which is on topic for this thread, sort of!)

ken brydson

KennethSwauger wrote: »

Thanks, Mark, I'll post some more when I get the roll developed (just kidding).

On your way home from returning those video tapes, right?

vmaxer

ken brydson wrote: »

KennethSwauger wrote: »

Thanks, Mark, I'll post some more when I get the roll developed (just kidding).

On your way home from returning those video tapes, right?

Be kind, rewind

vmaxer

Analog/digital

Film/digital

Could be another "cable discussion"

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