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Thread: Small amp for 2405?

  1. #31
    Senior Member Lee in Montreal's Avatar
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    In regard of a power amp for that 2405, am I the only one having problems when using amps with output relays? After a while, the relay o one side stops kicking in. And will work only at higher volume. I had two amps do that one me... I tend to believe that the 2405 needs so litte power that it affects the relays.

  2. #32
    Senior Member Doc Mark's Avatar
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    Quote Originally Posted by BMWCCA View Post
    Hey Doc,

    I pulled the trigger on a D45 recently and it arrived today. Looks like new. Playing it with some small sacrificial JBLs right now to "burn" it in. Sounds very nice! It's hooked up to a Soundcraftsmen PRO PT-TWO sitting atop a spare PS400 and PS200 in the same room for testing and evaluation. This brings the Crown collection to (at least one of each) D45, D75A, D150, D150A-II, DC300A-II, PS200, PS400, PL3, Studio Reference-II, plus SL2, FM2, FM3, VFX2-A.

    How's your project coming? I'm all set now to resurrect the 030 system in bi-amp form. All I need is space and time!
    Evening, BMWCCA,

    Phil, I'm still waiting for Ken (Edgewound) to finish refoaming the 2245's. The surrounds he had did not fit as well as he had hoped, so he had to order new ones. His work is so fine, it's worth the wait, so I'm ready when he's ready! I was very happy with the sound of both the D45, and the D150AII I recently received, and interestingly enough, even that Peavey CS1200X sounded pretty good, with no extra hiss or noise, other than the fan, which is a bit too much of a good thing, at least to me. I have given thought to checking into a quieter fan, and will contact Peavey to see what they might recommend. In the old days, we used "Whisper fans", and they seemed to work well. But, that's been many years ago, and I need to see what's out there today.

    Thanks for letting me know about your own D45, and congrats on getting a nice one, as did I!! Well done!! Your Crown collection is outstanding, and something to be admired. I'm looking forward to moving forward with my project, whenever the 2245's are ready to go. Take care, and God Bless!

    Every Good Wish,
    Doc
    The only thing that can never be taken away from you, is your honor. Cherish it, in yourself, and in others.

  3. #33
    Heather [Senorita member] hjames's Avatar
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    Quote Originally Posted by Lee in Montreal View Post
    In regard of a power amp for that 2405, am I the only one having problems when using amps with output relays? After a while, the relay o one side stops kicking in. And will work only at higher volume. I had two amps do that one me... I tend to believe that the 2405 needs so litte power that it affects the relays.
    ... the 2405s really don't need much power at all!
    How about using one of those T-amps -
    they are mighty cheap and pretty clean.

    I'm not triamping my L200 3ways, but its certainly worth a try ...
    Seems like $25 is a worthwhile price to try one, doncha think?
    http://www.amazon.com/Upgraded-LP-2020A-Lepai-Amplifier-Shipping/dp/B00C2P61FO/


    I got one of these around Christmas and have been playing with it -
    my original plan was to amp an iPod with a pair of walnut Minimus 7 speakers,
    but I tried and was amazed what I did with a pair of Ruark Talisman II speakers.
    It WILL get noisy if you push too far, but below that point its very impressive!

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    2ch: Oppo, JoLida 502CRC, JBL L212, 18ti,240ti; Heath AS101, Von Schweikert VR4
    7.1: Oppo BDP103D, B&K, UREI 809A, JBL B460

  4. #34
    Senior Member 1audiohack's Avatar
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    Quote Originally Posted by Lee in Montreal View Post
    In regard of a power amp for that 2405, am I the only one having problems when using amps with output relays? After a while, the relay o one side stops kicking in. And will work only at higher volume. I had two amps do that one me... I tend to believe that the 2405 needs so litte power that it affects the relays.

    I have experienced this also with amps driving HF horns.

    Barry.
    If we knew what the hell we were doing, we wouldn't call it research would we.

  5. #35
    Senior Member BMWCCA's Avatar
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    Quote Originally Posted by hjames View Post
    ... the 2405s really don't need much power at all!
    How about using one of those T-amps -
    they are mighty cheap and pretty clean.

    I'm not triamping my L200 3ways, but its certainly worth a try ...
    Seems like $25 is a worthwhile price to try one, doncha think?
    http://www.amazon.com/Upgraded-LP-2020A-Lepai-Amplifier-Shipping/dp/B00C2P61FO/


    I got one of these around Christmas and have been playing with it -
    my original plan was to amp an iPod with a pair of walnut Minimus 7 speakers,
    but I tried and was amazed what I did with a pair of Ruark Talisman II speakers.
    It WILL get noisy if you push too far, but below that point its very impressive!
    Lots of attractive little amps out there these days. Just like there are many Chinese DACs available for pocket change. I'm amazed at what these small SS Crowns will do with even the lowest-level small speakers. And they don't need wall-warts for power, I feel good having something else actually Made in USA, and they seem to work forever. If I lined up all my Crown amps for which I'd paid within ten-bucks of a hundred-dollars for they would include a D45, D75A, DC300A-II, PS400, and more. Not knocking the the T-amps. I find the technology rather astounding and the bang-for-the-buck hard to overestimate.

    I went to the normal Crown support site for "discontinued" amps and couldn't find a tech sheet on the D45. Then I remembered it was still in production, at least until recently, so it was still supported in the current-products section. A quick Google search showed new prices as high as over $700. I patted myself on the back once more.

    Maybe I spent four-times as much for an honest 25wpc at 8-ohms but I can tell you this D45 also makes an absolutely incredible headphone amp! Maybe one day I'll splurge for a Lepai and do some A-B comparisons. I did notice that one Amazon review noted that those more satisfied with the Lepai are using better speakers than those who are less happy with their purchase.

    Off to work I go. Enjoy your Sunday.
    ". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers

  6. #36
    Senior Member Lee in Montreal's Avatar
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    Quote Originally Posted by 1audiohack View Post
    I have experienced this also with amps driving HF horns.

    Barry.
    Next amp I use to power some 2405 wil have no output relay. And they'll have to have no popping on actuation/deactuation.

  7. #37
    RE: Member when? subwoof's Avatar
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    D75 popping

    Many of the older "D" series amplifiers have that turn-off "thump" when the amp is turned off.

    Most of the time it can be traced to the change in value of the small electrolytic caps used on the +/- 10V supply. The zener diodes were mounted too close to the dropping resistors and too close to the caps so all would heat up and the caps would dry out...amongst other issues.

    When I repair / restore these I replace the dropping resistors and the caps with higher wattage and higher temp ( 105C vs 85C ) to ensure long (new) life. Still it is found sometimes that different loads will cause the supplies to drop differently and the thump is still there so changing the cap size usually fixes this.

    The PS amplifiers have an additional Cmos audio switch ( chip ) that breaks the connection from the input opamp chip to the power stages which eliminates this problem.

    I have a stack of D60/D75 amps here in the house I am restoring and when done I will get to the D150's and 300's.. probably 60 amps in total of this series. anybody need power?? too cold to do anything except solder........


  8. #38
    Senior Member 1audiohack's Avatar
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    Quote Originally Posted by subwoof View Post
    anybody need power?? too cold to do anything except solder........

    I do. VZ power. :^)

    Also, all my D75's pop when powered down and none of my D45's do. I thought it was just the way they were. If that's not the case I need to look and see if I can fix them.

    Barry.
    If we knew what the hell we were doing, we wouldn't call it research would we.

  9. #39
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    Quote Originally Posted by subwoof View Post
    Many of the older "D" series amplifiers have that turn-off "thump" when the amp is turned off.

    Most of the time it can be traced to the change in value of the small electrolytic caps used on the +/- 10V supply. The zener diodes were mounted too close to the dropping resistors and too close to the caps so all would heat up and the caps would dry out...amongst other issues.

    When I repair / restore these I replace the dropping resistors and the caps with higher wattage and higher temp ( 105C vs 85C ) to ensure long (new) life. Still it is found sometimes that different loads will cause the supplies to drop differently and the thump is still there so changing the cap size usually fixes this.

    Does anyone know what capacitors he was talking about here? My D45A amps all make a thump or a pop when turned off, and this one was really bad. R1 and R2 were very hot at one time, so I'm thinking D1, C11, and C2 should be replaced with the corresponding components around R2.

    I should be able to solder in new components myself.
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  10. #40
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    Regardless of the amp choice you may want to consider a DC blocking cap in series with the 2405. Something like a 6uf would put the cap cutoff well below the where your most likely crossing into the 2405.

  11. #41
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    I'm going through the same issues right along with you, Robert.

    So far I've tried the D45(pristine and newer model), a 1U QSC unit, and two UREI 6215. I've managed to get one UREI 6215 working out of two. Both the Crown and the QSC exhibit DC on shutdown. The working UREI has a 60Hz hum that I'm still troubleshooting. I put a Solen 5.6uf (protection on HP@7KHz)on the outputs and measured both shutdown DC and hum through this capacitor.

    Took a chance on another 6215 that had severe chassis damage. The board showed up super clean. It has 2mv constant on one channel that I'm not able to adjust out and that's it. No other DC voltage detected anywhere on power up or down. One of the few 1U amplifiers with a relay on the outputs is what I'm finding. I will be doing the maintenance, swapping it into the clean chassis, and adding a perforated hood so it can breath.

    I've looked into the class D stuff, but I don't understand the output protection on them if there is any at all. I've also looked into what Greg Timbers is using on his Everest tweeters. It is a Pioneer Elite integrated with a "bypass" or "direct" button.

  12. #42
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    Quote Originally Posted by Mike Caldwell View Post
    Regardless of the amp choice you may want to consider a DC blocking cap in series with the 2405. Something like a 6uf would put the cap cutoff well below the where your most likely crossing into the 2405.
    I have a couple of these that I am going to use for protection, 5.6uf.
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  13. #43
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    Quote Originally Posted by grey View Post
    I'm going through the same issues right along with you, Robert.

    So far I've tried the D45(pristine and newer model), a 1U QSC unit, and two UREI 6215. I've managed to get one UREI 6215 working out of two. Both the Crown and the QSC exhibit DC on shutdown. The working UREI has a 60Hz hum that I'm still troubleshooting. I put a Solen 5.6uf (protection on HP@7KHz)on the outputs and measured both shutdown DC and hum through this capacitor.

    Took a chance on another 6215 that had severe chassis damage. The board showed up super clean. It has 2mv constant on one channel that I'm not able to adjust out and that's it. No other DC voltage detected anywhere on power up or down. One of the few 1U amplifiers with a relay on the outputs is what I'm finding. I will be doing the maintenance, swapping it into the clean chassis, and adding a perforated hood so it can breath.

    I've looked into the class D stuff, but I don't understand the output protection on them if there is any at all. I've also looked into what Greg Timbers is using on his Everest tweeters. It is a Pioneer Elite integrated with a "bypass" or "direct" button.
    I bet you bought that UREI 6215 that has been on eBay for a while? I have one that works perfect, and two with problems. They both have a tittle distortion at really low volumes. I bought them not working and my tech went through them. The STK chip was replaced and my tech thinks they are counterfeit. I gave up throwing money at them.

    I'm almost of thinking of getting a six channel amplifier for the top three of my four-way. I've been looking at a Crown CP660 and an Elan A6 on eBay. Both are really cheap, but I can't find much information on them. Hopefully I can get these old D series Crown going with a few dollars in parts instead of buying something else.

  14. #44
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    Quote Originally Posted by robertg View Post
    I bet you bought that UREI 6215 that has been on eBay for a while? I have one that works perfect, and two with problems. They both have a tittle distortion at really low volumes. I bought them not working and my tech went through them. The STK chip was replaced and my tech thinks they are counterfeit. I gave up throwing money at them.

    I'm almost of thinking of getting a six channel amplifier for the top three of my four-way. I've been looking at a Crown CP660 and an Elan A6 on eBay. Both are really cheap, but I can't find much information on them. Hopefully I can get these old D series Crown going with a few dollars in parts instead of buying something else.
    Yeah, the ebay beater. Made an offer on it and it is way cleaner on the inside compared to the other two. Measured it and tested on a cheap speaker. The first one that i purchased had enough heat buildup to lift the pcb traces. A 6215 the hard way.

    Another option for multi-channel are the BGW units. They likely need a maintenance update as well unless they have a modern version.

  15. #45
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    I bought a couple of Ramsa WP-9055 amps off eBay. They were $100.00 each, new in the box, and they have a muting circuit on start up so no pop.
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