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DIY amp for 600 ohm dt880 - Page 2

post #16 of 25
9/15/09 at 3:13pm
Quote:
Originally Posted by 00940 View Post
sanderx: just a minor correction. The m³ with opa604@40v will give roughly 22Vp-p (7.77Vrms). So you won't even go above the max power handling.
Yes, you are right. I managed to get myself severly confused during writing what I wrote and dropped a factor of 2 a couple of times, the edit hopefully fixed some of that.

Uncle Eric is right in saying that people who want to go to tubes should go to tubes. With the caevat that they shouldn't go to tubes because solid state / opamp based amplifiers supposedly don't have enough voltage swing.
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post #17 of 25
9/17/09 at 5:06pm
Thread Starter 
First of all, thank you all for the responses!

OK well I don't really have any desire to get tubes so it's great to hear I could get great sound from the 880/600 ohm with something solid state.

Sanderx, i'm sorry i'm not very fluent in the electronics language yet...are you showing through your calculations that even a cmoy could power these cans well enough? I would assume that a mere cmoy would severely underpower them.
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post #18 of 25
9/18/09 at 7:20pm
Re: the CMoy; with a +/- 15V supply, the output voltage (symmetrically) maxes out at 25V p-p for a 600 ohm load on an OPA2134. Granted, the impedance of the driver will vary w.r.t. frequency, but that's a good ballpark.

EDIT: Do note that the THD of the OPA2134 starts to climb dramatically after about 12V p-p output (~9V RMS) which is, eh, ~15 mA for a 600 ohm load, which is ~135 mW, which is less than 3dB lower than the SPL produced at an input power of 200mW. 1.7dB lower, to be exact.
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post #19 of 25
9/19/09 at 5:22am
Thread Starter 
Hmm...ok then what would a good suggestion for a DIY amp be? M^3 continues to appeal to me. AMB mentioned a PPA being used with the 990/600... would that work alright with the 880? I know that would probably be easier to build than an M^3 and cheaper too right?
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post #20 of 25
9/19/09 at 5:49am
Quote:
Originally Posted by Ub3rMario View Post
I know that would probably be easier to build than an M^3 and cheaper too right?
No and no
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post #21 of 25
9/19/09 at 8:20am
Thread Starter 
Well crap i'm just embarrassing myself now lol.
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post #22 of 25
9/19/09 at 12:31pm
2x parallel opa2604,+/24 Vsupply "A47" style or just 2 parallel amps with ~10 Ohm resistors in series with outputs should be pretty good with 600 Ohm load and is about as simple as it gets

HeadWize - Project: Apheared's Project Scrapbook by Michael Shelton
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post #23 of 25
9/20/09 at 10:47am
Quote:
Originally Posted by jcx View Post
2x parallel opa2604,+/24 Vsupply "A47" style or just 2 parallel amps with ~10 Ohm resistors in series with outputs should be pretty good with 600 Ohm load and is about as simple as it gets

HeadWize - Project: Apheared's Project Scrapbook by Michael Shelton
I thought it was more for low impedance phones, high current output.
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post #24 of 25
9/20/09 at 10:50am
Why not a starving student? Those supposedly have enough power, don't they?
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post #25 of 25
9/20/09 at 2:06pm
Quote:
Originally Posted by bidoux View Post
I thought it was more for low impedance phones, high current output.
the circuit increases output current capability - usually op amps have much lower distortion at less than ~1/2 their max rated output current so I would parallel the OPA2604 even for 600 Ohm load - using the high V opa2604 op amps and high Vsupply to match the 600 Ohm load V requirements

i r a engineer...
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