DAX616 Posted March 24, 2004 Share Posted March 24, 2004 I'm looking at a crown d75a. Has someone used one in the past. It has a damping factor of "greater than 400 from DC to 400Hz". What does from DC to 400Hz mean?Isn't this spec given @1 kHz. It has a slew rate of 6 volts per ms. I have read the slew rate should be at least 10 for the 40 watt per channel range. The damping factor looks good @ 400 and it should deliver good bass.Right?Thanks for your impressions. Dax Quote Link to comment Share on other sites More sharing options...
Shock-Late Posted March 24, 2004 Share Posted March 24, 2004 Dax, I have no experience with crown amps and they're supposed to be very good. That said, one shouldn't judge an amp by it's technical specs. I recently bought a second-hand, "technically unbeatable" very high end SEA5 technics amp, wich was technics' flagship series beginning 80's. Sounds like crap to me, even tho slew rate, damping factor and speed are among the best I've ever encountered... What's more, i'm not sure a high damping factor is good with high efficiency horn loaded speakers. Can make them sound thin at low volumes. Quote Link to comment Share on other sites More sharing options...
leok Posted March 24, 2004 Share Posted March 24, 2004 The Crown may have pretty high distortion at low power, which will make efficient horn speakers sound harsh and thin. I used a rack-mounted crown for a while, with KHorns, in an electronic music studio. I don't know the model .. it was not much more than a single rack position in height, but it was not a good combination. Leo Quote Link to comment Share on other sites More sharing options...
JohnA Posted March 24, 2004 Share Posted March 24, 2004 Since the mass of the woofer cone far exceeds the mass of the other drivers, and damping factor is a measure of the amp's ability to control come motion, damping factor is mostly applicable to bass frequencies. Damping factor is the speaker impedance divided by the amp's output impedance. The mass of the woofer's cone pushing the voice coil can act as a generator. A shorted generator is difficult or impossible to turn (move). The lower the output impedance, the closer the amp gets to a "short". Some say more than 400 is pointless. Quote Link to comment Share on other sites More sharing options...
rigma Posted March 24, 2004 Share Posted March 24, 2004 I have some Crown amps in very good condition that I would sell, DC-75 & DC-150 Series II. Make reasonable offer. mb Quote Link to comment Share on other sites More sharing options...
CaptnBob Posted March 24, 2004 Share Posted March 24, 2004 The D-75A and its forbearers, the D-40, D-60, and D-75, were well thought of "in the day," as being well built and probably the best sounding of the Crown amps - not as "wirey" as the bigger units. A writer whose opinion I respect, Mark Tobak, said the D-60 produced "some of the sweetest, most natural sounding output available." (Audio Alternative, p. 41, Tobey, 1975) Of course, he liked Phase Linear 400s too. I've used a couple of these amps and found them OK, but nothing to get excited about. Also, beware of mechanical noise. Several "pancake" amps like the D-75, JBL, and BGW can have significant transformer hum. This varies from unit to unit, but can be an extremely annoying trait. Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted March 24, 2004 Share Posted March 24, 2004 ---------------- On 3/24/2004 6:22:21 PM CaptnBob wrote: The D-75A and its forbearers, the D-40, D-60, and D-75, were well thought of "in the day," as being well built and probably the best sounding of the Crown amps - not as "wirey" as the bigger units. A writer whose opinion I respect, Mark Tobak, said the D-60 produced "some of the sweetest, most natural sounding output available." (Audio Alternative, p. 41, Tobey, 1975) Of course, he liked Phase Linear 400s too. I've used a couple of these amps and found them OK, but nothing to get excited about. Also, beware of mechanical noise. Several "pancake" amps like the D-75, JBL, and BGW can have significant transformer hum. This varies from unit to unit, but can be an extremely annoying trait. ---------------- Bob, I have looked for the proper word to describe the DC-300 sound. Thanks, "Wirey" is right on the money. Terry Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted March 24, 2004 Share Posted March 24, 2004 ---------------- On 3/24/2004 5:22:28 PM rigma wrote: I have some Crown amps in very good condition that I would sell, DC-75 & DC-150 Series II. Make reasonable offer. mb ---------------- mb, is it DC-75, DC-150.....or D-75 and D-150????? Regards, Terry Quote Link to comment Share on other sites More sharing options...
D-MAN Posted March 24, 2004 Share Posted March 24, 2004 I have an IC/DC150 amp and preamp from the '80s that I no longer use. The published specs are outstanding even today. I believe that the damping factor is the highest in the industry. They are also very "bullet-proof". For the money, they should be amongst the top performers in the below $1000 price range. Otherwise, I would recommend used McIntosh or the like. DM Quote Link to comment Share on other sites More sharing options...
rigma Posted March 24, 2004 Share Posted March 24, 2004 ---------------- On 3/24/2004 6:49:08 PM IB Slammin wrote: ---------------- On 3/24/2004 5:22:28 PM rigma wrote: I have some Crown amps in very good condition that I would sell, DC-75 & DC-150 Series II. Make reasonable offer. mb ---------------- mb, is it DC-75, DC-150.....or D-75 and D-150????? Regards, Terry ---------------- Sorry they are D-75 and a D-150A Series II, I have 2 of each. mb Quote Link to comment Share on other sites More sharing options...
djk Posted March 25, 2004 Share Posted March 25, 2004 "Bob, I have looked for the proper word to describe the DC-300 sound. Thanks, "Wirey" is right on the money" Broken glass is how I think of them. "They are also very "bullet-proof"." The D150 is a POS, one of the worst sounding and most unreliable amps Crown ever made. I had to sell and service them. Quote Link to comment Share on other sites More sharing options...
DAX616 Posted March 25, 2004 Author Share Posted March 25, 2004 Thanks for the input once again. Crown has a return policy.They are about 467.00 new (D75a) I may audition one in about a month once I complete my basement modifications.The proof is in the pudding. The hafler 220 has dynamite specs as well, I didn't care for it on my Khorns. It may be because it's 20 years old. I found it shrill and lacking pronounced midrange. Dax Quote Link to comment Share on other sites More sharing options...
CaptnBob Posted March 25, 2004 Share Posted March 25, 2004 The DC-300s - especially the early ones - were noted for unit to unit variation. I thought they were bullet-proof too, until I had one go south during a sound reinforcement gig. No, it was not Twisted Sister or anything - it was a string quartet. Anyway, one channel began to crackle and got very hot. I took it to the repair shop and found out every output transistor and a few other parts had been massacred. It would have been over $350 to fix it. I wish I could say I came up with "wirey" to describe the Crown sound, but I must admit I cribbed it from Bob Shaw, the longtime St. Louis Bozak dealer. (I'd repeat what he said about Klipsch, but I don't want to get the forum shut down again!) Quote Link to comment Share on other sites More sharing options...
IndyKlipschFan Posted March 25, 2004 Share Posted March 25, 2004 d75A are in about 95% of every radio station control rooms I have ever been in. With highly efficient Heritage line Klipsch speakers, you will never need to crank the amps up too much. They are built in Elkhart, Indiana. USA workers I believe, and a chasis like TANKS!! I personally heard the d75A's with Klipsch Conwalls...not a sit down really listen over a long time liten critique... But sounded pretty damn good to me! Quote Link to comment Share on other sites More sharing options...
D-MAN Posted March 25, 2004 Share Posted March 25, 2004 ---------------- On 3/25/2004 4:52:55 AM djk wrote: "Bob, I have looked for the proper word to describe the DC-300 sound. Thanks, "Wirey" is right on the money" Broken glass is how I think of them. "They are also very "bullet-proof"." The D150 is a POS, one of the worst sounding and most unreliable amps Crown ever made. I had to sell and service them. ---------------- As for sounding like POS, well, I can't argue there. As for being "wirey-sounding", make that a nasty, scratchy copper wiring sound and you've got the idea. To me, they sound just like a new Sony or the like. As for being "bullet-proof", mine were bought used in 1981, and they STILL WORK fine. They were originally used by a bass player as his main amp head bridged mono. They were only treated nicely as audio gear after I bought them... What suprizes me is that they are now worth more used than when they were new. DM Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted March 25, 2004 Share Posted March 25, 2004 ---------------- On 3/25/2004 4:52:55 AM djk wrote: "Bob, I have looked for the proper word to describe the DC-300 sound. Thanks, "Wirey" is right on the money" Broken glass is how I think of them. "They are also very "bullet-proof"." The D150 is a POS, one of the worst sounding and most unreliable amps Crown ever made. I had to sell and service them. ---------------- djk, I was trying to be diplomatic. Probably some around the BB. What did you think of the M-400 & M-600? Regards, Terry Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted March 25, 2004 Share Posted March 25, 2004 Bob, What would you expect from a Bozak dealer? Terry Quote Link to comment Share on other sites More sharing options...
djk Posted March 26, 2004 Share Posted March 26, 2004 "What suprizes me is that they are now worth more used than when they were new" The D60/D75 may be close, depends on what year you bought them. They actually bring more than the D150 because of their one rack space size. The D75 sounded the best of the D75/D150/DC300 trio, the D150 was the least reliable. The D150 was 1/2 the power of the DC300, but only had 1/4 the number of output transistors. You ever own a car you didn't want to sell to anybody you knew? That's how I feel about Crown, unfortunately, I still have four Crown amps in my collection. "What did you think of the M-400 & M-600?" The front end on an M600 looks about like a Carver M1.5T, much better than what they used on the D75/D150/DC300. If you need a one rack space amplifier the BGW100 blows away the Crown. PWK sent out a Dope from Hope on this amplifier in the late 70s (stating) that it had the lowest TIM of any amplifier he had tested to date. Curves were presented showing that the Heresy caused the BGW to have even less distorton than when driving an 8 ohm resistor. Quote Link to comment Share on other sites More sharing options...
D-MAN Posted March 26, 2004 Share Posted March 26, 2004 yeah, well, I actually traded a Phase Linear 400 stack straight up for the Crown gear in 1980-ish. At the time I thought it was an improvement... I got down on PWK for owning Crown gear on the "PWK's amps" thread, but what-the-hell, I had the same thing too...on Khorns too! DM Quote Link to comment Share on other sites More sharing options...
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