Which op-amp is better for HD580 - OPA627 or AD8610/20?
Mar 25, 2006 at 2:33 AM Thread Starter Post #1 of 29

kevin1592

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Hey Guys!

I was wondering which op-amp would be better with the Sennheiser HD580, the Burr Brown OPA627 or the AD8610/20? Thanks for your input. All recommendations are appriecated.

Kevin.
 
Mar 25, 2006 at 3:02 AM Post #3 of 29

saturnine

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Depends on the application. I prefer the AD-8610 with HD-580/600/650 when used with a PPA. The OPA-627/637 is also good, yet less energetic sounding IMO.
 
Mar 25, 2006 at 3:06 AM Post #4 of 29

kevin1592

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Well I am talking to MisterX about building me a PIMETA and they come with OPA627, but I have read a lot of people saying that they like the 580/AD8610 combo. So I ask again which is better? Oh, and I really can't afford both. Thanks!

Kevin
 
Mar 25, 2006 at 3:14 AM Post #5 of 29

Oski

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Quote:

Originally Posted by kevin1592
Well I am talking to MisterX about building me a PIMETA and they come with OPA627, but I have read a lot of people saying that they like the 580/AD8610 combo. So I ask again which is better? Oh, and I really can't afford both.


Good call on getting MisterX to build an amp, great guy and top quality work! If you can afford the very expensive OPA627 in the PIMETA, the AD8610 should probably not be more than an additional $10-$12...so you might as well try both and see which ones you like better...then sell the ones you don't like.
 
Mar 25, 2006 at 3:25 AM Post #6 of 29

kevin1592

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Thanks Oski, Actually I didn't ask for the OPA627, I just asked MisterX what kind of amp he could build me with a max $200 budget, and he just gave me the specs which included the OPA627. And I'm already pushing it, because the amp that he recommended was actually $220 after shipping and paypal fees.

Here's the specs of the PIMETA, please tell me if there are better options or if I should just stick with whats there.

MisterX Portable PIMETA

Tangent's PIMETA Circuit Board
Burr Brown OPA627 opamps, Left & Right channels (socketed)
Burr brown OPA627 opamp, ground channel (socketed)
5 BUF634 output buffers. (socketed)
(two each for left and right channels, one for ground channel)
4 Elna Cerafine 470uf 25v power supply capacitors
Hand matched Vishay/Dale 1% metal film resistors
Wima 6.8uf reservoir capacitors
JFET Cascode class A bias
R11 resistors added to optimize buffer bandwidth
Cardas CTFA RCA input jacks
Re'an ¼” headphone jack
Alps "Blue Velvet" 50k potentiometer
Kilo international silver knob with soft touch rings
Mountain mini toggle switch (front or rear mounted)
Closed circuit 2.5 mm locking DC power jack
(automagicly turns off the batteries when something is plugged into it)
Reverse polarity protection
You choice of LED color
Gain set to individual requirements (5 in this case)
Silver Hammond 1455 enclosure (4.72”L x 4.062”W x 2.09”H)
Bulgin dual 9 volt battery trays.
AC power is provided by an external wall wart.

I have no idea what all that means, so please tell. Thanks!

Kevin.
 
Mar 25, 2006 at 3:57 AM Post #7 of 29

cmirza

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It depends on what kind of sound you want with your headphones. AD8620 will give you a bright, agressive sound, OPA627 will give you a more warm, laid back sound. Rock music? Definately AD8620. Accostic, Jazz music? OPA627.

I just recieved my MisterX PIMETA with pretty much the same specs as yours, but no battery trays and AD8620s. They sounds great with my HD580s. I have a set of OPA627s that I recently orderd to use with my more agressive Grado headphones.

I see it like this: bright headphones use OPA627s, mellow headphones use AD8620. I'm sure there is alot more to consider depending on who you are and what equipment you use. But in my case, it boils down to that.
 
Mar 25, 2006 at 4:11 AM Post #8 of 29

kevin1592

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Thank you Cmirza, so are you saying that with rock music, the AD8620? Because almost all my music I listen to is Rock and Alternative. So the AD8620 is the best? Thank you all.

Kevin
 
Mar 25, 2006 at 4:55 AM Post #9 of 29

jcx

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on a strictly technical basis I would recommend dropping the dual buffers to just 1 per output, with the HD580’s 300 Ohm load the extra output buffers are simply silly, you only need 30 mA to swing 9 V on the HD580, the BUF634 can do 250 mA apiece

even more unsound is the use of 2 buffers on each output when the active ground has to soak up both channel's current and you're being offered only 1 buffer in this position - the ground channel really deserves as many buffers as the sum of the output channels, but for the HD580’s 2 x 250 mA ground buffers would be overkill

The 300 Ohm headphone impedance means you want every last Volt of output swing, I would look for the 9.6 V rechargeable "9 V" battery for this application (Maha?) - if you pay no attention you could end up with a 6 cell, 7.2 V "9 V" rechargeable, or the 8.4 V ones

by dropping the unnecessary paralleled buffers you make up somewhat for the lower mAHr of the higher Voltage batteries

http://www.thomas-distributing.com/mh-96v170.htm


a downside of the AD8610 is the +/- 13 Vmax supply rating, with the 300 Ohm Senns you want all the voltage swing possible and the 8610’s reliability would be iffy with a 24 V unregulated wall wart supply

The AD823 is very well regarded, cheaper than either previously mentioned op amp and swings rail-rail on the output with up to +/- 18 V supplies
 
Mar 25, 2006 at 5:17 AM Post #10 of 29

kevin1592

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Well, originally, I had asked MisterX for the recommended configuration for the Sennheiser HD555's (50 ohms), because thats what I was going to buy, but now the HD580's have me intrigued so its actually my mistake not MisterX's. Sorry for the confusion. I'll ask MisterX again for the recommended configuration for the HD580's and then maybe you guys could shed some light on what I should get.

Thanks
Kevin.
 
Mar 25, 2006 at 6:40 AM Post #11 of 29

cmirza

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My old setup was a Go-Vibe w/ OPA2227 (another laid back Burr-Brown opamp like the OPA627) and Alessandro MS-1s. I really liked this setup for rock music. Now with a Pimeta w/ AD8620 and Sennheiser HD580, I'm starting to lean twoards the Sennheisers. The open soundstage of the HD580s combined with the agressive AD8620s make a great combination. My MS-1s on the Pimeta w/ AD8620s feels a bit too bright and hard however. That why I picked up some OPA627s to tame my Pimeta when using Grado headphones.
 
Mar 25, 2006 at 7:01 AM Post #12 of 29

chesebert

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Quote:

Originally Posted by jcx
on a strictly technical basis I would recommend dropping the dual buffers to just 1 per output, with the HD580’s 300 Ohm load the extra output buffers are simply silly, you only need 30 mA to swing 9 V on the HD580, the BUF634 can do 250 mA apiece

even more unsound is the use of 2 buffers on each output when the active ground has to soak up both channel's current and you're being offered only 1 buffer in this position - the ground channel really deserves as many buffers as the sum of the output channels, but for the HD580’s 2 x 250 mA ground buffers would be overkill

The 300 Ohm headphone impedance means you want every last Volt of output swing, I would look for the 9.6 V rechargeable "9 V" battery for this application (Maha?) - if you pay no attention you could end up with a 6 cell, 7.2 V "9 V" rechargeable, or the 8.4 V ones

by dropping the unnecessary paralleled buffers you make up somewhat for the lower mAHr of the higher Voltage batteries

http://www.thomas-distributing.com/mh-96v170.htm


a downside of the AD8610 is the +/- 13 Vmax supply rating, with the 300 Ohm Senns you want all the voltage swing possible and the 8610’s reliability would be iffy with a 24 V unregulated wall wart supply

The AD823 is very well regarded, cheaper than either previously mentioned op amp and swings rail-rail on the output with up to +/- 18 V supplies



..uh...stacking buffer is to lower your output imp.....which = better sound ...
ideal is 0ohm ofcourse, you know increase transient current draw, better slew...you know all good stuff when you stack
biggrin.gif
 
Mar 25, 2006 at 7:36 AM Post #14 of 29

chesebert

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op627 with pimeta is a waste of money.....been there done that...now back to 8620 on pimeta...my PPA luv op627 in the mean time.
 
Mar 25, 2006 at 7:41 AM Post #15 of 29

spike33

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With my HD650, I prefer OPA637s, fast and lively yet warm with deep bass. OPA627 is too slow and laidback in comparison. Some prefer the brighter AD8610 with senns but I found them too fatiguing in the upper mids.
 

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