It's almost the same as this one except it doesn't have the 3/4/5 channel selector switch and the speaker plug is slightly different
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=270258007295&ssPageName=STRK:MEWA:IT&ih=017
There's a sticker on it that says Fulet Electronic Industrial Company.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=270258007295&ssPageName=STRK:MEWA:IT&ih=017
There's a sticker on it that says Fulet Electronic Industrial Company.
It seems they did oem work for several other brands so it's hard to say what brand it was marketed as. It's quite a bit bigger than any Proton amp I've seen. Here's a pic next to one of my SS MC300's for size comparison
An externally hosted image should be here but it was not working when we last tested it.
Proton's 250 was a fairly large amp for 2x50W. I have a service manual somewhere for that one, give me a day or so and I'll dig it up if you want to look it over.
BTW, the 250 was an excellent amp, one of my all-time favorites.
Seems like it compared very favorably with Zapco's 151 in a white paper they published, where other top names didn't do so well...
BTW, the 250 was an excellent amp, one of my all-time favorites.
Seems like it compared very favorably with Zapco's 151 in a white paper they published, where other top names didn't do so well...
CA90ss:
The Crown Suspect is most of a triplet of Proton 250’s. Looks like the soft-clipping circuit and speaker level inputs may not be there. A single 250 was about 6” by 12” and stood on little legs for ventilation.
At the time the Proton version was produced (early 80’s), they only marketed the 250 and its little brother the 222. They were both very good sounding amps, evidently targeting the ADS P100 and P40 as competition. I liked the Protons better. Neither brand was built for bassheads who hadn’t quite emerged yet, but I did run a few 222’s on 10” woofers with good results. I was told Proton products were actually NAD products by a few Proton reps and NAD dealers, and similarities are evident.
There’s a bank of switches outlined on the board, but not in place:
SW201 is the Hi/Low input selector, and goes straight into the 4559 op-amp labeled IC 201. That *is* the gain control, as in 2 choices- speaker level or preamp level. You could replace/modify the voltage divider there for adjustable gain if it’s important to you.
SW202 turns on/off the ‘Soft-Clipping’ circuit that Proton used on virtually every amp they made (home and car) in the 80’s. NAD also used this circuit. Looks like a limiter that works to reduce the output of the buffer?
SW203 is the bridging switch, and could make 3/4/5 channel options easier for your amp.
I had to crop and compress this scan to post, hopefully it's at least visible...
The Crown Suspect is most of a triplet of Proton 250’s. Looks like the soft-clipping circuit and speaker level inputs may not be there. A single 250 was about 6” by 12” and stood on little legs for ventilation.
At the time the Proton version was produced (early 80’s), they only marketed the 250 and its little brother the 222. They were both very good sounding amps, evidently targeting the ADS P100 and P40 as competition. I liked the Protons better. Neither brand was built for bassheads who hadn’t quite emerged yet, but I did run a few 222’s on 10” woofers with good results. I was told Proton products were actually NAD products by a few Proton reps and NAD dealers, and similarities are evident.
There’s a bank of switches outlined on the board, but not in place:
SW201 is the Hi/Low input selector, and goes straight into the 4559 op-amp labeled IC 201. That *is* the gain control, as in 2 choices- speaker level or preamp level. You could replace/modify the voltage divider there for adjustable gain if it’s important to you.
SW202 turns on/off the ‘Soft-Clipping’ circuit that Proton used on virtually every amp they made (home and car) in the 80’s. NAD also used this circuit. Looks like a limiter that works to reduce the output of the buffer?
SW203 is the bridging switch, and could make 3/4/5 channel options easier for your amp.
I had to crop and compress this scan to post, hopefully it's at least visible...
Attachments
tsmith,
Thanks for the info. Good to know what the missing switches are for. Luckily the boards are labeled pretty well. SW201 and 202 are missing but there are pins where SW203 goes and on the section that is bridged has a couple jumpers soldered across the pins. Looks like it's just a matter of adding/removing the jumpers for stereo/bridged operation.
Thanks for the info. Good to know what the missing switches are for. Luckily the boards are labeled pretty well. SW201 and 202 are missing but there are pins where SW203 goes and on the section that is bridged has a couple jumpers soldered across the pins. Looks like it's just a matter of adding/removing the jumpers for stereo/bridged operation.
I can send you the whole set of readable scans if you'd like, just send me an email. Schematics, board layouts, etc.
jol:
Proton's home division called it 'Anti-Clipping Circuitry', and the button was labeled ACC. It may be that the light isn't on until it clips, I can't remember.
If you'd like the 250 schematic to see how it was implemented, send me an email.
I know, but I just had to. Maybe this is why some old amps are worth so much:
(290251398849, Alpine mrv-f300, 4x30/40rms@4/2ohm@12v, 4x50/60rms @14.4v)
"You are bidding on a slightly used Alpine 1200 watt, 4/3/2 channel amp. This is a great sounding amp and really loud. I actually set off numerous car alarms using this amp, and sadly I have got pulled over for it being too loud. There are a few scratches on it and one missing screw, however it does not affect the quality of the amp. The amp is in prestine working condition. It is the clearest sounding amp on the market right now! Retail price is well over $350.00! Very low reserve !!! Thanks for looking !"
(290251398849, Alpine mrv-f300, 4x30/40rms@4/2ohm@12v, 4x50/60rms @14.4v)
"You are bidding on a slightly used Alpine 1200 watt, 4/3/2 channel amp. This is a great sounding amp and really loud. I actually set off numerous car alarms using this amp, and sadly I have got pulled over for it being too loud. There are a few scratches on it and one missing screw, however it does not affect the quality of the amp. The amp is in prestine working condition. It is the clearest sounding amp on the market right now! Retail price is well over $350.00! Very low reserve !!! Thanks for looking !"
I'd love to know
IMO they are good amps, but their ratings sure are closer than that. I've read they make around 5-10w more than rated. Not to mention that the very newest that amp could be is mid 90s, I know late 90s were the mrv-Fxx2/5/7/etc. not 0. There are some great laughs on there.
Seems ironic at times; I have a mrd-m301 350rms class d alpine like new I bought for $35 shipped. Put that 4ch where it belongs running highs; I can't believe people buy or sell them for subs in that power range....oh wait I forgot this one has 1200watts
IMO they are good amps, but their ratings sure are closer than that. I've read they make around 5-10w more than rated. Not to mention that the very newest that amp could be is mid 90s, I know late 90s were the mrv-Fxx2/5/7/etc. not 0. There are some great laughs on there.Seems ironic at times; I have a mrd-m301 350rms class d alpine like new I bought for $35 shipped. Put that 4ch where it belongs running highs; I can't believe people buy or sell them for subs in that power range....oh wait I forgot this one has 1200watts
Not a bad price for a Zed $26 shipped
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=110276565375&ssPageName=STRK:MEWA:IT&ih=001
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=110276565375&ssPageName=STRK:MEWA:IT&ih=001
Boss amplifiers
We produced Boss, Soundstorm, Planet Audio and USacoustics all at the same time using almost the same circuits.
Of course the heat sinks were all different and the features as well.
The Hybrid Planet amps had tubes in the front end.
The high end Planet amps used BJTs (Large Toshiba) devices.
If any one wnats some of these Boss amps I stll have some, they are brand new and are "dirt" cheap.
Steve Mantz
Zed Audio Corp.
We produced Boss, Soundstorm, Planet Audio and USacoustics all at the same time using almost the same circuits.
Of course the heat sinks were all different and the features as well.
The Hybrid Planet amps had tubes in the front end.
The high end Planet amps used BJTs (Large Toshiba) devices.
If any one wnats some of these Boss amps I stll have some, they are brand new and are "dirt" cheap.
Steve Mantz
Zed Audio Corp.
Some of the "old school" stuff is far superior to what is being churned out today - most of it originating from China.
[I'm not totally sure why people use the phrase "old school" - when "old" or "vintage" would be just as effective and user-friendly and were quite Ok 15 years ago!]
Back in the 70s and 80s, companies were more interested in producing high quality and good sound, than mass marketing of cheap junk to the consumer.
Perreaux (a NZ company) made some excellent power amps (home audio) of which I own a couple and they are still considered to be one of the best amps (Mosfet) ever made.
Anyway, I'd really like to find some of the old silver-face, high end Alpine head units.
In the 80s they put out a "component" system - seperate tuner, tape deck and graphic equaliser with spectrum analyser on it.
From memory, the tuner was a 1301, the graphic was a 3015 and the tape deck I can't remember!
I know I still have all the old Alpine product catalogs from back then - they're in storage. One day I'll dig them out and possibly scan the photos, put them up on a "Hall of Fame" vintage audio website.
[I'm not totally sure why people use the phrase "old school" - when "old" or "vintage" would be just as effective and user-friendly and were quite Ok 15 years ago!]
Back in the 70s and 80s, companies were more interested in producing high quality and good sound, than mass marketing of cheap junk to the consumer.
Perreaux (a NZ company) made some excellent power amps (home audio) of which I own a couple and they are still considered to be one of the best amps (Mosfet) ever made.
Anyway, I'd really like to find some of the old silver-face, high end Alpine head units.
In the 80s they put out a "component" system - seperate tuner, tape deck and graphic equaliser with spectrum analyser on it.
From memory, the tuner was a 1301, the graphic was a 3015 and the tape deck I can't remember!
I know I still have all the old Alpine product catalogs from back then - they're in storage. One day I'll dig them out and possibly scan the photos, put them up on a "Hall of Fame" vintage audio website.