moviola tubes -- other names?

[John Bessa]

I am having trouble finding these tubes, are there any other names they go by?

These are the tubes in the schematic:

• 12AX7
• 6AQS
• 6X4

Thanks in advance, John

[mctavish]

Originally Posted by John Bessa

I am having trouble finding these tubes, are there any other names they go by?

These are the tubes in the schematic:

• 12AX7
• 6AQS
• 6X4

Thanks in advance, John

12AX7, 6AQ5, 6X4, some VERY common tubes. Google IS your friend.

[DigitalJunkie]

I"m sure Jim McShane could hook you up.
http://pages.prodigy.net/jimmcshane/

(No affiliation other than a happy repeat customer.)

[kevinkr]

NOS for 6X4 and 6AQ5 are cheap and readily available on eBay. 12AX7A is in current production from a number of sources and some NOS (but not most) is reasonably priced on eBay.

Antique Electronic Supply, thetubestore, and many others will have most or all of these types in stock.

Moviola was probably nothing more than a rebrander (Maker of that amp? I don't think I have even heard of them before), but tubes from Sylvania, RCA, GE, Tungsol, Amperex, Rogers, etc., will work just fine.

[Eli Duttman]

Kevin,

IIRC, a "moviola" is something a film editor uses.

[Poindexter]

Maybe it takes audio off the projector or something, Eli. That amp has a ton of gain in the front end. Cascaded 12AX7s? Lord.

Poinz

[Eli Duttman]

The O/P from a photocell that "reads" an optical sound track is small enough. Perhaps cascaded 'X7 sections are just what the doctor ordered.

[bichela]

Originally Posted by Poindexter

Maybe it takes audio off the projector or something, Eli. That amp has a ton of gain in the front end. Cascaded 12AX7s? Lord.

Poinz

Thats because a magnetic tape head is plugged into the input. I got to build one of these for my cinematograpy studio and film sync block.

[barrymagrec]

This amp presumably comes from a Moviola Film editing table and must date from the 50`s / early 60`s. O/P levels from optical heads were very low then so you would need lots of gain, one unit I know of used an EF86 followed by an ECC81 and was still marginal getting the signal up to line level. The O/P from a mag head is even lower and you would want some EQ even for editing so I would assume this was an optical monitoring amp. The valves should be easy and cheap to obtain, several equivalents available - 12AX7 / ECC83, 6AQ5 / EL90, 6X4 / EZ90 to name but a few.

Barry

[Jim McShane]

Originally Posted by DigitalJunkie

I"m sure Jim McShane could hook you up.
http://pages.prodigy.net/jimmcshane/

(No affiliation other than a happy repeat customer.)

I'd be happy to help if needed. Probably you'd want a couple low noise 12AX7s with all the gain.

BTW, pardon the pop up if you go to my site - AT&T at its finest!