Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › Matrix Quattro amp: unboxing and initial impressions
New Posts  All Forums:Forum Nav:

Matrix Quattro amp: unboxing and initial impressions - Page 10

post #136 of 193
Quote:
Originally Posted by Chris J View Post


The little red ones are between the big Nichons and BR1 and BR?
Probably a bypass cap on the outputs of BR1 and BR2.
I'm quite surprised that it smoked!

I would store the dual amp you smoked in the garbage. redface.gif

BR1 and BR2 are next to the little tin box?
They would be bridge rectifiers for the Power Supply.

 

Thanks for the info!

 

Is there any way to test the bridge rectifiers with a test meter or are they not likely to have fried?

post #137 of 193
Quote:
Originally Posted by Loquah View Post

Thanks for the info!

Is there any way to test the bridge rectifiers with a test meter or are they not likely to have fried?

The short answer is if you still have +/-15 Vdc coming out of the power supply then the rectifiers are OK.

Long answer:
240 Vac goes into transformer
Transformer feeds BR1 and BR2
Which then go to the 2 big power supply caps
Which then go to the 2 voltage regulators.

The regulators are short circuit protected, so they should be OK, so destroying the OPA627 would probably not harm anything else.
Try plugging a single ended headphone into Solo 1 and then Solo 2 jacks.
If you get sound out of both Solo jacks then you should be good to go.
post #138 of 193
I guess you have an OPA627 data sheet?

If you don't, pin 8 is +15 Vdc, pin 4 is -15 Vdc.
post #139 of 193

Thanks Chris!!!

post #140 of 193

Can I stretch the friendship and ask if anyone knows the size and type of resistor I'd use to replace C61? They look like Panasonic metal caps and normal bypass theory is 1% of the main cap I believe so should I be getting 4.7uF metal caps?

post #141 of 193
Quote:
Originally Posted by Loquah View Post

Can I stretch the friendship and ask if anyone knows the size and type of resistor I'd use to replace C61? They look like Panasonic metal caps and normal bypass theory is 1% of the main cap I believe so should I be getting 4.7uF metal caps?

Is it possible you can post a photo of C61 here?
It's hard to see it on the photos posted at the beginning of this thread.

I suspect it is for rejecting high frequency noise.
If it really is for rejecting high frequency noise, then replacing it with a 4.7 uF metal can cap is not a good idea.
The 4.7 uF cap will not do much at high frequencies.

Plastic film and ceramic capacitors are superior at frequencies above 100 kHz - 1 mHz.
Edited by Chris J - 2/21/14 at 9:46am
post #142 of 193
Quote:
Originally Posted by Chris J View Post


Is it possible you can post a photo of C61 here?
It's hard to see it on the photos posted at the beginning of this thread.

I suspect it is for rejecting high frequency noise.
If it really is for rejecting high frequency noise, then replacing it with a 4.7 uF metal can cap is not a good idea.
The 4.7 uF cap will not do much at high frequencies.

Plastic film and ceramic capacitors are superior at frequencies above 100 kHz - 1 mHz.

 

Thanks again. Here's a pic. It's a tricky angle...

 

 

The cap itself is about 3mm high and 4-5mm long. I can't see any labelling or signs of damage, but maybe I'll take it out of the circuit to see.

post #143 of 193

Sorry mate......sorry for the delay.......um....busy!

I have a bad habit of leaving my account logged in for hours on end.....................even though I'm not "on line".

 

From the photo the cap looks like a plastic metal film cap.

Probably used to suppress bridge rectifier switching noise.

It doesn't seem to be damaged.

I suppose you could take it out and test it if you have a capacitance meter, but I would not replace it with another value.


Edited by Chris J - 2/22/14 at 7:10am
post #144 of 193
Quote:
Originally Posted by Chris J View Post
 

Sorry mate......sorry for the delay.......um....busy!

I have a bad habit of leaving my account logged in for hours on end.....................even though I'm not "on line".

 

From the photo the cap looks like a plastic metal film cap.

Probably used to suppress bridge rectifier switching noise.

It doesn't seem to be damaged.

I suppose you could take it out and test it if you have a capacitance meter, but I would not replace it with another value.

 

No sweat on the delay - I really appreciate the help.

 

Matrix have provided some very helpful guidance to help me test for a fault so I'll try that and let you know what comes of it in case this situation ever strikes someone else here...

post #145 of 193

Sure,  I'd love to hear what Matrix says about all that.

 

I'm sure Op Amp rollers put the replacement Op Amp in backwards all the time.

 

I did it once....it wasn't pretty...:angry_face:

post #146 of 193
Quote:
Originally Posted by Chris J View Post
 

Sure,  I'd love to hear what Matrix says about all that.

 

I'm sure Op Amp rollers put the replacement Op Amp in backwards all the time.

 

I did it once....it wasn't pretty...:angry_face:

 

Finished testing and the test points which should read around 10mV were all 3-4V!?

 

What's confusing is that the OPA2107 sounds like it's ok despite being reversed and getting hot enough to burn my fingers (long story). Do you think there's any chance it survived?

post #147 of 193
Quote:
Originally Posted by Loquah View Post
 

 

Finished testing and the test points which should read around 10mV were all 3-4V!?

 

What's confusing is that the OPA2107 sounds like it's ok despite being reversed and getting hot enough to burn my fingers (long story). Do you think there's any chance it survived?

 

I would junk the OPA2107.

I reversed an Op Amp once.

It worked fine for a few days, then it slowly deteriorated..........not pretty.

So I would not take the chance, just trash the OPA2107.

 

What test points measure 3-4 Volts?

post #148 of 193
Quote:
Originally Posted by Chris J View Post
 

 

I would junk the OPA2107.

I reversed an Op Amp once.

It worked fine for a few days, then it slowly deteriorated..........not pretty.

So I would not take the chance, just trash the OPA2107.

 

What test points measure 3-4 Volts?

 

I can't remember the numbers, but it's the pads in between each pair of resistors in front of the heat sinks. There are 4 pairs of resistors and the centre pads of each pair should read around 10mV.

post #149 of 193
Quote:
Originally Posted by Loquah View Post

I can't remember the numbers, but it's the pads in between each pair of resistors in front of the heat sinks. There are 4 pairs of resistors and the centre pads of each pair should read around 10mV.

10mV to Ground?
post #150 of 193
Quote:
Originally Posted by Chris J View Post


10mV to Ground?

 

I assume so - the instructions weren't really clear. I used the pads where the screws mount the PCB to the chassis as my earth which seems to yield good, consistent readings.

 

I've since realised that I had AD843 op amps installed instead of the stock OPA604s though. New readings are much closer to 10mV, but still a little high and higher on one pair than the other (ranging from 11-12mV up to around 14mV on the higher pair).

New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Headphone Amps (full-size)
Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › Matrix Quattro amp: unboxing and initial impressions