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Bought a Crown IC 150 SS preamp at a sale today. It is unfamiliar to me. Apparently, from the bit of research I've managed, there were 150's and 150A's. I know Crown had a bigger rep in the Pro side of audio.
If anyone has info, please feel free.
Thanks,
Pete
Follow Ups:
I had one, and found that its sound was notably affected by how clean the pots were -- even though there wasn't the sort of crackling etc that generally is a sign that Deoxit is needed, an application made it sound much better. Maybe not great, but much better, even pretty acceptable. Haven't found this to be the case with other preamps.
He said it was a find!
I had one for about a week or two, and I think that it could really move some speakers with old-fashioned lead surrounds, or maybe even wake up some speakers assumed to be totally dead.
That's a special quality that shouldn't be dismissed, right?
Jeez Pete, you seem to be on a mission to champion every dubious design of excellent manufacture out there. I am pretty sure there's a germanium and selenium preamp in your future.
But until that day comes, you should include among the naysayers of the Crown 150 the actual Crown company, themselves. Consequently, you can download for free any information you might need to improve your preamp. The link is included.
You might also look into the Audio Amateur back issues for the rebuild information on your preamp. From what I could see, the phono circuit looks like a goner. But any section which is op amp based can be made to sound great by figuring out how to incorporate modern op amps made by Analog Devices or Linear Technology. Also, whenever you see a 2-5uf electrolytic cap used as a coupling cap in the original schematic, plan on replacing with a 2-5uf/100V film cap. That alone should at least update you toward the end of the 20th century.
Good luck, Bob
Yes, this stuff comes to me. I (almost) never spend much money for them and it can be fun.
Thanks for the link. I just read the factory recommendations for replacing certain parts "due to high failure rate" - that does not build confidence.
I will look inside this Crown thing this week.
Pete
a non-working McIntosh 2100 SS power amp. I am kidding about giving me crap -- I value your opinions (And those of doodlebug and Jerry, George, nightdoggy, etc.) My "mission to champion every dubious design of excellent manufacture out there" continues! This 2100 amp has its detractors, but many more supporters, I believe.
Doodlebug is like me, tries to find something good to say. =8^D
I appreciate the generous advice since everyone knows more than me about this cool vintage stuff.
I will likely be asking advice about this Mac 2100 amp - researching it now. Should be able to find a schematic.
Pete
worst sounding thing imaginable with a pair of Klipsch Cornwalls.
I keep my MC-2100 in a box in the attic (no mean feat getting it up there, either). When its worth enough, off it goes! Alternatively, I'll trade anyone interested any Mac stereo tube power amp in working (or at least restorable) condition for it :-)
I b'lieve the service manual is on-line (Belgian fanboy site?)... If you cannot find it, e-mail me.
There was also an article on refurbishing the MC-2100 in audioxpress a while back. You can check at www.audioxpress.com or send me an e-mail if the topic is of interest.
all the best,
mrh
Thanks for the info about MC-2100 in audioexpress. If you have the article, I would be grateful for an email attachment. Would like to see that very much.
What is the "Belgian fanboy site"? - I haven't seen it in a search.
I ordered schematic along with service notes.
Thanks, Mike
Pete
rw
I was dumb enough to buy one of the very first ones, in fact the manual that came with it was photocopie of a few typed pages marked "Preliminary". It sounds royally harsh through the Koss 2 ESL speakers I had at the time. I ended up gutting it and building a discrete transistor circuit in it from an Audio Amateur magazine article.
Dave
If you are up to it, changing out the 4558 (basically a dual 741) op amps, ceramic and tantalum caps will make a huge difference.
The electrolytics used are also poor by today's standards. They were good for ten years tops and are undoubtedly "dried out".
You can do all of the above for less than $40. "Boutique" caps. are not at all necessary, imo.
doggy
There's nothing Wrong with the 4558. Its the caps (all of them) that need to go.
Nichicon Muse electrolytics and audio-grade Mylars will do wonders. Make shure the opamp's are biased into class-a.
If you want to try a different opamp, Burr-Brown's 2132 is an allround good drop-in replacement.
I was hoping to find one of these for cheap and do just that. So keep quiet! (Just kidding!)
Dave
I will be looking into applying your suggestions.
Thanks,
Pete
I remember reading on this forum that it was not a great preamp. I just listened to it - it's not THAT terrible. When compared to my McIntosh C24 (not exactly the best itself) the Mac had a much fuller sound, the Crown is just thinner. I have not listened to Phono yet. Out of fairness, this 150 has been in storage, very dusty in and out. I will clean up pots switches, etc. Maybe I'll use it for PA. Or sell to someone who wants it for nostalgic purposes.
Yes, the promotion touts it as 'integrated circuit', like that was a hi-tech improvement. Probably seemed like it at the time. I like the Power On light.
At least I got a nice Pioneer TX-7500 tuner at the same place!
Pete
The thinness might well be due to coupling caps that are dried out and way under spec value. That would act to roll off the low end.
How's the phono section, as compared to the line stage.
I had a PAT-4, another infamous preamp, and found the line stage was decent; but the phono amp was awful. probably accounting for its bad rep.
Jerry
the original version, that is. Do a search here and you'll find a number of references to them. They have do have a bit of a bad rap these days as they were built with op amps that were new at the time but now understood not to be that good.
Also the use of then-new tantalum caps is not considered the best use of this component - there are quite a few in much of Crown's product line of the day as well as many other vendors. These will need to be replaced as they become leaky and will cause all sorts of problems during playback.
All that said, Crown achieved a well-deserved reputation for making nearly bullet-proof power amps. Almost all the disco installations in the mid-70s used them mainly because they would tolerate all sorts of abuse. They did have some sales through high end audio salons back then but much more of the DC-300 amps went to traveling bands - I was in one of those, too.
Lastly, they made some of most heavy-duty tape decks, too, as well as a couple of electrostatic speakers. All were _very_ expensive and out of the range for a college student/musician like me. So their product line was broad at their peak.....
Hope that helps a bit.
Cheers,
David
as ugly as it looks.
I think it sounds much worse than it looks.. :)
Dave
that preamp is... well, kinda legendary in its own way.
rw
How about notorious?
Jerry
I believe infamous is the word you are looking for.
nt
rw
nt
all the best,
mrh
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