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chevin research amplifiers

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stayin View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote stayin Quote  Post ReplyReply Direct Link To This Post Posted: 30 October 2017 at 5:28pm
Hi Cameron it's Alan from Stayin Alive can you please give me a phone number to contact you ? I lost all my phone numbers ! thanks Al
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tonysparks69 Quote  Post ReplyReply Direct Link To This Post Posted: 30 October 2017 at 9:05pm
The output transistors used were Exicon ECF20N20 and ECF20P20. these can be replaced by BUZ901D and BUZ906D.
Down load the transistor specs of both types and have look they are identical.
I have repaired a lot of Chevins in the past and used these transistors and never had one come back.
When Chevins were used by Logic in Gainsborough these were the transistors that they used in their repairs.
If you really want to use the Exicon ones they are still available from www.profusionplc.com but they are expensive.
As for the fans they were two 24V fans wired in series, I agree it was a bad design. I replaced them with 48V fans wired in parallel across the two outside connections.
Tony
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Post Options Post Options   Thanks (0) Thanks(0)   Quote simonp1100 Quote  Post ReplyReply Direct Link To This Post Posted: 30 October 2017 at 9:49pm
The fan circuit in the Chevins is the most badly designed ever, most of the time when it fails tends to take out both 24 volt fans as well. Repaired so many of these with dodgy fans and drive circuit. TerribleConfused
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DirtyDiscoABZ Quote  Post ReplyReply Direct Link To This Post Posted: 18 January 2020 at 7:10pm
Even tho these Chevin amps have had common faults and repairs , when repairing or modifying them have they proven to be more reliable work horses , also with the 50 - 100 hz processing is there such noticeable audio difference?
Just as am looking into getting a set of these amps with a system and be keen to mod them before they fail and is there parts out there still buy for these amps if anything goes wrong with them ? 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Digbethdave Quote  Post ReplyReply Direct Link To This Post Posted: 18 January 2020 at 7:39pm
Originally posted by DirtyDiscoABZ DirtyDiscoABZ wrote:

Even tho these Chevin amps have had common faults and repairs , when repairing or modifying them have they proven to be more reliable work horses , also with the 50 - 100 hz processing is there such noticeable audio difference?
Just as am looking into getting a set of these amps with a system and be keen to mod them before they fail and is there parts out there still buy for these amps if anything goes wrong with them ? 
They sound nice. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote macabre1993 Quote  Post ReplyReply Direct Link To This Post Posted: 30 April 2021 at 11:28pm
Hello, this is my first post to speakerplans.com, thanks for the add!

I'm looking at a brace of used Chevin Research A2500 monoblocks for sale online @ $500USD per amp. Thinking of using them at home to power a pair of ML Motion 12s initially and later a set of Apogee Centaurs after their ribbons are repaired. 

Any members with experience/thoughts/opinions? Any answers are appreciated,  thanks.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote kedwardsleisure Quote  Post ReplyReply Direct Link To This Post Posted: 01 May 2021 at 3:37pm
I'm no home audio expert but these amps are designed for large PA systems in discos etc. Aren't they going to be a bit of overkill for a hifi?
Kevin

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Post Options Post Options   Thanks (0) Thanks(0)   Quote toastyghost Quote  Post ReplyReply Direct Link To This Post Posted: 01 May 2021 at 5:14pm
Originally posted by kedwardsleisure kedwardsleisure wrote:

I'm no home audio expert but these amps are designed for large PA systems in discos etc. Aren't they going to be a bit of overkill for a hifi?


Well, if they like listening to music then they probably want an amplifier with 16 times their average listening level power output as headroom to ensure they have sufficient juice for clean peak signals. That’s assuming a 12 dB crest factor, of course. If they like jazz, then the range is higher…
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Post Options Post Options   Thanks (0) Thanks(0)   Quote macabre1993 Quote  Post ReplyReply Direct Link To This Post Posted: 01 May 2021 at 6:43pm
The Apogees are current-hungry ribbon hybrids. I was driving them with a sweet old QSC 3800 and it put out juice like crazy. Sometimes they dip below two Ohms so they require a pretty robust power amp...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JBK Quote  Post ReplyReply Direct Link To This Post Posted: 03 May 2021 at 12:35pm
Just tested an a500 on my home audio setup this weekend, looots of headroom of course, but the fan noise is something to consider if the amp is in the listening room. At a "normal" (as in "i live in a flat and don't like police ringin on my doorbell" normal) the fan noise is very noticeable.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote macabre1993 Quote  Post ReplyReply Direct Link To This Post Posted: 03 May 2021 at 6:12pm
Originally posted by JBK JBK wrote:

Just tested an a500 on my home audio setup this weekend, looots of headroom of course, but the fan noise is something to consider if the amp is in the listening room. At a "normal" (as in "i live in a flat and don't like police ringin on my doorbell" normal) the fan noise is very noticeable.
For whatever reason, I thought they were passively cooled so I won't be buying them. I have a Yamaha and Carver PA amps with fans, and my beloved old passively cooled QSC3800 is in the shop. I'm using a nice little Rotel power amp with the Motion 12s and that's adequate for now. Thank you all for your input.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ypa Quote  Post ReplyReply Direct Link To This Post Posted: 28 January 2022 at 4:06pm
Hello everyone,
Does anyone know how to modify voltage input on a A3000 ?
Thanks
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