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-   -   Old Penncrest stereo console, who made it and should i get it? (http://www.videokarma.org/showthread.php?t=267912)

mr_fixer 10-17-2016 05:14 PM

Old Penncrest stereo console, who made it and should i get it?
 
Hello All! Sat. at the local GW i spy a console stereo out of the corner of my eye. It is branded Penncrest, it is a tube model, with 11 tubes on one chassis, My curiosity is up so i go home and try to find out more info about it with Google. It is a model 662fm-a and the only pic of it is from a SAMS Photofact manual for sale on the -bay. evidently this is the only that has survived or it is a piece of junk no one thought worth the time to snap a pic and upload it to the web.
A few strange things i have noticed about it are, audio output uses 1 7686 pentode in singled ended operation per channel. It uses a straight line magic eye tube for tuning like European and McIntosh Tuners. thirdly this stereo uses a outboard demultiplexer for FM stereo "missing or never installed in this unit". Anyone have one of these or know who made it for JCP? Or if it is worth picking up? The price is $50 today and $25 next Sun.
Thanks all, Logan

Electronic M 10-17-2016 08:21 PM

I'd get it when it is $25. You can probably add any tube MPX adapter....Using that adapter dates it somewhere in the 1959-63 range, by my reckoning. Single ended can sound VERY good if the engineers bothered to make it good.

Findm-Keepm 10-18-2016 09:40 AM

Quote:

Originally Posted by Electronic M (Post 3171929)
I'd get it when it is $25. You can probably add any tube MPX adapter....Using that adapter dates it somewhere in the 1959-63 range, by my reckoning. Single ended can sound VERY good if the engineers bothered to make it good.

Or make your own - I've built two using MC1310P ICs - easy-peasy, just with the datasheet schematic. The chip doesn't require a bunch of odd parts, and will drive a 70ma or less stereo lamp. First went with a Channel Master table radio that had a mux adapter output, and the second went in a Bradford consolette radio/phono I got from a couple at church. It's now in a Pennsylvania dentist's hands.

http://www.datasheetarchive.com/dl/6...ecoder+mc1310p

dieseljeep 10-18-2016 10:02 AM

Quote:

Originally Posted by mr_fixer (Post 3171919)
Hello All! Sat. at the local GW i spy a console stereo out of the corner of my eye. It is branded Penncrest, it is a tube model, with 11 tubes on one chassis, My curiosity is up so i go home and try to find out more info about it with Google. It is a model 662fm-a and the only pic of it is from a SAMS Photofact manual for sale on the -bay. evidently this is the only that has survived or it is a piece of junk no one thought worth the time to snap a pic and upload it to the web.
A few strange things i have noticed about it are, audio output uses 1 7686 pentode in singled ended operation per channel. It uses a straight line magic eye tube for tuning like European and McIntosh Tuners. thirdly this stereo uses a outboard demultiplexer for FM stereo "missing or never installed in this unit". Anyone have one of these or know who made it for JCP? Or if it is worth picking up? The price is $50 today and $25 next Sun.
Thanks all, Logan

I tried looking up the output tube number and that number doesn't come up as an output tube. It could be a 5686 or???
It's possibly built by Symphonic or another east coast maker.
It could be similar to the Bradford that used a single ELL80 dual output tube.

Electronic M 10-18-2016 11:08 AM

Quote:

Originally Posted by Findm-Keepm (Post 3171961)
Or make your own - I've built two using MC1310P ICs - easy-peasy, just with the datasheet schematic. The chip doesn't require a bunch of odd parts, and will drive a 70ma or less stereo lamp. First went with a Channel Master table radio that had a mux adapter output, and the second went in a Bradford consolette radio/phono I got from a couple at church. It's now in a Pennsylvania dentist's hands.

http://www.datasheetarchive.com/dl/6...ecoder+mc1310p

Fascinating. I may have to try that (if I can source the chips).

DavGoodlin 10-18-2016 11:36 AM

Quote:

Originally Posted by Electronic M (Post 3171968)
Fascinating. I may have to try that (if I can source the chips).

I built a project in school to decode and re-generate MTS stereo from a composite audio input, using my Sony 7" TV-720 to demonstrate.
It was easier to adapt an NTE-743, which is a similar IC to the MC1310, a Motorola chip.

As I fuzzily recall 30 years later, the range of the pilot tone generator on the NTE (an LM-something) could be tuned to 15.7 kHz. But the Motorola IC was designed to be stable at 19 kHz and varying it did not work well.

Findm-Keepm 10-18-2016 12:15 PM

Quote:

Originally Posted by DavGoodlin (Post 3171971)
I built a project in school to decode and re-generate MTS stereo from a composite audio input, using my Sony 7" TV-720 to demonstrate.
It was easier to adapt an NTE-743, which is a similar IC to the MC1310, a Motorola chip.

As I fuzzily recall 30 years later, the range of the pilot tone generator on the NTE (an LM-something) could be tuned to 15.7 kHz. But the Motorola IC was designed to be stable at 19 kHz and varying it did not work well.

March 1986 Radio-Electronics has the project for an MTS Stereo decoder using the MC1310 - it's a versatile chip....

tom.j.fla 10-18-2016 01:18 PM

You will find in the Jan. & Feb. 1987 RADIO-ELECTRONICS a write-up on a tv stereo decoder with signal processing using an LM1800 & SA570 chips. Was a good design. All the best,Tom.J

Electronic M 10-18-2016 02:04 PM

Dang it, now I've got 2 more scratch project builds i want to do...You guys are a bad influence. :D

DavGoodlin 10-18-2016 03:00 PM

Quote:

Originally Posted by tom.j.fla (Post 3171978)
You will find in the Jan. & Feb. 1987 RADIO-ELECTRONICS a write-up on a tv stereo decoder with signal processing using an LM1800 & SA570 chips. Was a good design. All the best,Tom.J

Gee Tom, That's WHEN it was! I had the delusion I came up with that myself. It was the LM1800 tho' :sigh:

WISCOJIM 10-18-2016 03:17 PM

This is probably the multiplex that originally came in your (Wells-Gardner) Penncrest:

http://www.searchinforums.com/st/con...-tube-amp/4546

Maybe you can buy it from him.

.

mr_fixer 10-18-2016 06:28 PM

Quote:

Originally Posted by dieseljeep (Post 3171962)
I tried looking up the output tube number and that number doesn't come up as an output tube. It could be a 5686 or???
It's possibly built by Symphonic or another east coast maker.
It could be similar to the Bradford that used a single ELL80 dual output tube.

Yep, 7686 there are 3 for sale on the bay. here is a link to a tube data page.
http://www.nj7p.org/Tubes/PDFs/Frank...ngham/7868.pdf

OOPS i meant 7868 time to get new glasses!

mr_fixer 10-18-2016 07:15 PM

Quote:

Originally Posted by WISCOJIM (Post 3171987)
This is probably the multiplex that originally came in your (Wells-Gardner) Penncrest:

http://www.searchinforums.com/st/con...-tube-amp/4546

Maybe you can buy it from him.

.

I haven't really made up my mind to get this stereo yet. Let me see if this stereo is still for sale on "half price day" I don't have alot of room and money. and it is heavy. It might be better to hold out for a better brand with multiplex already built in.

dieseljeep 10-21-2016 10:55 AM

Quote:

Originally Posted by mr_fixer (Post 3172001)
I haven't really made up my mind to get this stereo yet. Let me see if this stereo is still for sale on "half price day" I don't have alot of room and money. and it is heavy. It might be better to hold out for a better brand with multiplex already built in.

If the unit is still available, it's worth considering. If it's built by Wells Gardner and has SE 7868's it should be OK. The 7868 is RCA's answer to the Westinghouse 7591, a little better than a 6V6, but not quite a 6L6. Should be around 8WPC.
Some of those private label products were amazing! :thmbsp:

mr_fixer 10-23-2016 01:41 PM

4 Attachment(s)
Well i dun gone and did it. I am glad to be able to be the first person to post live pics of a Penncrest 662FM-a stereo console on the web.
I added some pics of the inside.


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