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  #1  
Old 10-17-2016, 06:14 PM
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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
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Old 10-17-2016, 09:21 PM
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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.
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Old 10-18-2016, 10:40 AM
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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
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Old 10-18-2016, 11:02 AM
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Originally Posted by mr_fixer View Post
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.
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Old 10-18-2016, 12:08 PM
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Originally Posted by Findm-Keepm View Post
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).
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Old 10-18-2016, 12:36 PM
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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.
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Last edited by DavGoodlin; 10-18-2016 at 12:41 PM.
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Old 10-18-2016, 01:15 PM
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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....
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Old 10-18-2016, 02:18 PM
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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
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Old 10-18-2016, 03:04 PM
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Dang it, now I've got 2 more scratch project builds i want to do...You guys are a bad influence.
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Old 10-18-2016, 04:00 PM
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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'
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Old 10-18-2016, 04:17 PM
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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.

.
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Old 10-18-2016, 07:28 PM
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Quote:
Originally Posted by dieseljeep View Post
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!

Last edited by mr_fixer; 10-18-2016 at 07:33 PM. Reason: mea culpa
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Old 10-18-2016, 08:15 PM
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Originally Posted by WISCOJIM View Post
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.
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Old 10-21-2016, 11:55 AM
dieseljeep dieseljeep is online now
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Originally Posted by mr_fixer View Post
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!
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Old 10-23-2016, 02:41 PM
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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.
Attached Images
File Type: jpg IMG_0308.jpg (91.1 KB, 68 views)
File Type: jpg IMG_0309.jpg (64.8 KB, 75 views)
File Type: jpg IMG_0310.jpg (79.4 KB, 65 views)
File Type: jpg IMG_0311.jpg (70.8 KB, 75 views)

Last edited by mr_fixer; 10-23-2016 at 06:32 PM. Reason: added inside pics
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