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CMOYBB JDS labs vs eBay build with BB

post #1 of 8
8/30/11 at 7:14am
Thread Starter 

Hi Forum,

 

Not sure whether to post this here or in portable amps, but I am looking to purchase a nice cheap portable amp. Reading through alot of the threads I read that CMOYBBs by JDS labs are one of better ones for under $100. When I ebayed cmoy alot of different amps did come up and because I have no experience in these I really don't know the differences in quality. 

 

I'm particularly looking at the JDS labs CMOYBB v2.03 but the shipping takes a while and  I'm impatient. So, upon ebaying I found a couple of CMOYs in Australia that look built and can be shipped quite quickly. The seller is fred_fred_2004 and it looks like he sells alot of these. I've attached the links below. Please help me out in which one I should buy. I'm gonna be using Shure SRH840 and Shure SE530 for these. I listen to electronica, techno and R&B so I do like my bass. 

 

Thanks!

 

1. JDS labs v2.03

 

2. OPA2132 BB: http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=200646281447#shId

 

3. OPA4227: http://www.ebay.com.au/itm/Cmoy-NEW-QUAD-POWER-OPAMP-Burr-Brown-OPA4227-/190566304468?pt=AU_Electronics_Audio_Amplifiers&hash=item2c5ea30ad4#ht_3459wt_1133

 

4. OPA2134 (Classic apparently): http://www.ebay.com.au/itm/Cmoy-Classic-Headphone-Amplifier-Burr-Brown-OPA2134-/190559767328?pt=AU_Electronics_Audio_Amplifiers&hash=item2c5e3f4b20#ht_4169wt_951

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post #2 of 8
8/30/11 at 4:36pm

You could try fred_fred2004's perfboard cmoy:- http://www.head-fi.org/t/460669/strip-board-cmoy-revisited

 

Use an NJM4556 if you can get one, don't settle readily for anything less. Aim for a gain of 2 or 4 to start with. The SE530 is a highly efficient IEM with 119dB SPL/mW and 56 ohms input impedance. Most things will easily drive these to deafening levels, a gain of 2 should be as much as you'll ever need. Build it with a dual rail 9V battery supply.

 

w

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post #3 of 8
8/30/11 at 4:45pm
Thread Starter 

Thanks for the answer!

 

I've actually just bought the OPA4227, but I am also asking him about the NJM4556 which he has for sale as well. Probably would ask for a swap + cash before he sends it.

 

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post #4 of 8
8/30/11 at 4:45pm

The seller of the ebay cmoy is fred_fred2004. Also his 4227 looks interesting
 

Quote:
Originally Posted by wakibaki View Post

You could try fred_fred2004's perfboard cmoy:- http://www.head-fi.org/t/460669/strip-board-cmoy-revisited

 

Use an NJM4556 if you can get one, don't settle readily for anything less. Aim for a gain of 2 or 4 to start with. The SE530 is a highly efficient IEM with 119dB SPL/mW and 56 ohms input impedance. Most things will easily drive these to deafening levels, a gain of 2 should be as much as you'll ever need. Build it with a dual rail 9V battery supply.

 

w



 

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post #5 of 8
8/30/11 at 4:58pm

don't go cheap with the NJM4556, wakibaki  only suggested it because he was assuming you'd build it using fred_fred tutorial. the NJM4556 is a cheaper opamp that doesn't performer that well unless under low gain. I think you should stick with your order a buffered cmoy is likely to preform much better, but I'm not sure about buffering  and amping using the same 4 channel opamp. also you should ask fred_fred2004 directly about tuning the amp to driver lower impendence headphone such as you're shures

 


Edited by Nagasaki_Kid - 8/30/11 at 5:11pm
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post #6 of 8
8/31/11 at 3:08pm

 

 

You only need low gain. The NJM4556 is a high-current opamp optimised for driver stages and is used by Grado in their single-chip RA1. It's rated 70mA into 150 ohms. In tests it showed up as the best DIP8 headphone driver. Despite its low cost it will almost certainly outperform the OPA4227 in this application, buffered or not, and cope with a wider variety of headphones.

 

Presumably Grado feel justified in charging $350-400 for the amp because of the money they spent researching the opamp. I don't imagine they omitted blind listening tests.

 

The OPA4227 is admittedly a DC precision opamp, rated 45mA into a short-circuit, it might compete if arranged in parallel, but the advert states 'buffered' which almost certainly means the amps are arranged in series.

 

The ultimate test of an opamp is the test, not the cost.

 

w

 

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post #7 of 8
8/31/11 at 3:38pm
Thread Starter 

I asked Fred yesterday about the NJM4556 and he told me that it would be better for me to go with the OPA4227 anyways, he told me that I didn't need the 18V, because the SE530s are easy to drive.

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post #8 of 8
9/6/11 at 8:20pm

try OPA27, this opamp sounds nice on CMOY bro

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