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Old 23rd April 2008, 03:06 PM   #311
AndrewT is offline AndrewT  Scotland
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Quote:
Originally posted by Moby
......... Situation is not so great OPA2134 are really hot, from 65 to 75 Celsius, and AKM DA's are around 65... PSU is 70-75. ............
Hi,
these must be surface temperatures.
What are the junction temps that create this mess?
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Old 24th April 2008, 03:29 AM   #312
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I measured inside the box with open top and then I removed the in/out board and measured the "down under" opa's. I checked the currents at GND's and it seems OK, like you stated... I will check the individual currents and post the result.
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Old 24th April 2008, 08:04 AM   #313
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Did i miss something ?

"OPA134 series op amps are capable of driving 600W loads with power supply voltage up to 18V. Internal power dissipation is increased when operating at high supply voltages."

How much is the supply voltage ? +/- 15 V ? or maybe higher ?

In my setup the hottest signal conditioning parts are the DSP Chips. And they are about 40..42C @ surface whiile AKM is about 36C. (When DEQ is set to "linear" EQ-Position and mostly blocks set to bypass. But when using more settings of DEQ then DSP can get up to 45 ... 50C. The more calculation the more heat dissipation In someway logic.

Another Question:
While listening to music, are you using the DEQ in balanced operation ? Or do you use XLR to RCA Adapter while using only the (hot +) wire output ? If so, then you could check also your soldering on OPA's for short circuit @ (- Input legs) That could force also power dissipation on the OPA.
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Old 24th April 2008, 12:17 PM   #314
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Quote:
Originally posted by artquake
Did i miss something ?

"OPA134 series op amps are capable of driving 600W loads with power supply voltage up to 18V. Internal power dissipation is increased when operating at high supply voltages."

How much is the supply voltage ? +/- 15 V ? or maybe higher ?

In my setup the hottest signal conditioning parts are the DSP Chips. And they are about 40..42C @ surface whiile AKM is about 36C. (When DEQ is set to "linear" EQ-Position and mostly blocks set to bypass. But when using more settings of DEQ then DSP can get up to 45 ... 50C. The more calculation the more heat dissipation In someway logic.

Another Question:
While listening to music, are you using the DEQ in balanced operation ? Or do you use XLR to RCA Adapter while using only the (hot +) wire output ? If so, then you could check also your soldering on OPA's for short circuit @ (- Input legs) That could force also power dissipation on the OPA.

PSU voltage is +/- 15V. I tried to lower the voltage and they are still hot BTW I have DCX not DEQ...but op-amp is still op-amp I'm using the unit in balanced mode...
One thing is for sure. Problem is something in general because I tried to completely remove analog board and I connected just +/-15V directly. Opa's are still hot. I checked the outputs with oscilloscope and I can't see any oscillation. Just a noise , at lower voltage setting . (I think that at 5mv) That noise is uniform too at all six outputs.... BTW, unit sounds OK
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Old 22nd October 2008, 03:15 AM   #315
Ryssen is offline Ryssen  Sweden
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The PSU in DEQ.

Click the image to open in full size. ''

Click the image to open in full size.

And it was worth the effort..

Now just have to change that oscillator..
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Old 22nd October 2008, 12:00 PM   #316
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How it sounds? At the end I removed linear PSU and returned to switching (original PSU). I had the "thump" on-of issue and have an impression that stock psu sounds better
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Old 22nd October 2008, 01:14 PM   #317
Ryssen is offline Ryssen  Sweden
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Voices are more upfront and treble more distinct,I think the original psu was more soft and laid back.
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Old 23rd October 2008, 05:00 PM   #318
Ryssen is offline Ryssen  Sweden
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Quote:
and have an impression that stock psu sounds better
Did you change the Oscillator to?

Have anyone else changed the PSU?
Impressions?
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Old 23rd October 2008, 07:40 PM   #319
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yes, I changed the oscilator op-amps and coupling capacitors. Everything resulted like improovement, especially capacitors. But as I mentioned before I had that on/of nasty thump so i returned back to the stock PSU. Maybe is something faulty with PSU but I bought it completed so I have to investigate. If I remember well noone but me has thump issue... Maybe I'm wrong??
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Old 23rd October 2008, 08:17 PM   #320
Ryssen is offline Ryssen  Sweden
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Quote:
If I remember well noone but me has thump issue... Maybe I'm wrong??
I to get a thump if I start the amlifier before DEQ..
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