The new "My Ref" Rev C thread

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ClaveFremen

ClaveFremen

Member
Joined 2005
inserra.it
Paid Member
Re: Re: Re: I'm slower......!!

jonclancy said:
Dario, did you link the other diodes then?
Click to expand...

You're welcome Jon!

I don't understand what you're meaning.

I've mounted MUR860s in DR1, DR2, DR3, DR4 and left empty B1 position.

bluegti said:
What sonic difference would I expect between the stock rectifier and using mur 860's?
Click to expand...

I don't know for sure because I've mounted directly MUR860s since I've had some at home...

But I remember that in another Myref thread (not the original one) someone reported improvements.
 
troystg

troystg

Member
Joined 2004
mhconley said:
I purchased a kit from one of the group buy participants that decided not to build it. I am gathering other pieces to complete my build. I'm stuck on the heat sink.

Can I use this small heatsink? (Jackson Audio Works used them.)

Or should I go with something beefier like these?

Martin
Click to expand...

Pay shipping and I have heat sinks for you.

Should be $5 for the flat rate box.

I'll take some pictures for you tomorrow. I sent some to another member <bluegti> and you can ask him what he thought of them.
 
A

AndrewT

R.I.P.
Joined 2004
those Jackson sinks are far too small.
Have a proper look at the National recommendation for the minimum size of heatsink required to take the junction temperatures up to the maximum of 150degC.
Now double their recommendation to get the junctions temperatures down to a much more sensible value.

That Ebay sink looks as though it may be able to cool a pair of 3886. But, it is far too expensive.
Find something similar in size for half the price.
 
J

jERiCOh

Member
Joined 2008
Hello everyone !
I finished my build last week and I must say that it sounds fantastic for the price.I'm hearing some kind of pink noise coming out of one of my channel and I was wondering if someone could help. :confused:

My readings just in case:

Pink noise board:
-2.60mVDC, 3.30mVAC
Dead silent board:
+0.31mVDC, 0.75mVAC
 
B

bluegti

Member
Joined 2004
troystg said:


Pay shipping and I have heat sinks for you.

Should be $5 for the flat rate box.

I'll take some pictures for you tomorrow. I sent some to another member <bluegti> and you can ask him what he thought of them.
Click to expand...

I tried using some small heatsinks at first and the sinks got really hot and the speaker protection kicked in making the amps screech and howl!

The heat sinks troy sent me work great. They barely get warm even after listening all day at work.
 
U

udailey

Member
Joined 2008
picasaweb.google.com/udailey/MyRef#
Are you SURE those are millivolts?
With that low of mV you should hear nothing on both but I dont know if anyone else is getting readings like that. You might want to check the owners manual of your DMM and make sure you mean mV. Maybe you are getting 260mV or 2.6V both of which are not good. When you turn it on does the speaker pop out and stay there and then when you turn it off does the speaker come to rest where it should be?
If so, this means a large amoung of DC is going to your speaker and you will fry it if you leave it on.
Get the DMM thing sorted first but you might want to try taking input ground and tying it to output ground and then tie output ground to the chassis/earth ground and take power ground to that same point. It worked for me.
Ri
 
J

jERiCOh

Member
Joined 2008
Well now i'm a bit confused. I selected the 200mV range on my old fluke 8050A. I typed what's on the screen. :scratch:

About my testing method, I switched everything from a channel to the other to isolate the problem to the board.

The results were taken with my source pluged in but I jumped ground and Input later to hear the same noise. I'll remeasure everything with inputs jumped and post my results and some pictures later this evening.
 
U

udailey

Member
Joined 2008
picasaweb.google.com/udailey/MyRef#
Maybe your DC measurements are right. Hope so as they would be very nice.
If you dont have DC problems I am not to sure what is giving you the noise you are talking about. Have you tried a different source or different pre? It seems you have isolated the noise to one channel so probably this is not a problem.
Baffled so far.
Your DMM at the 20V level will give resolution to 1mV. At 200mV you get 10uV resolution. So your measurements would have been extremely awesome!
Ri
 
troystg

troystg

Member
Joined 2004
jERiCOh said:
Hello everyone !
I finished my build last week and I must say that it sounds fantastic for the price.I'm hearing some kind of pink noise coming out of one of my channel and I was wondering if someone could help. :confused:

My readings just in case:

Pink noise board:
-2.60mVDC, 3.30mVAC
Dead silent board:
+0.31mVDC, 0.75mVAC
Click to expand...


Those are good measurements. THAT is not the reason for the noise.

If the boards were assembled correctly (good indication since they work) and one works right I am inclined to think "mounting / installation" issues, faulty IC, cold solder joint.

I have heard 2 distinct cases where a resister had a cold solder joint and created a well defined white noise. One was in my system, one was in a friends system. The friend made both units and admitted (after constant harassment) that he missed one solder joint completely, and the other was just a cold joint. Now this man has built hundreds of pieces of gear, and I can't even dream of building the stuff he builds. SO I harass him but he knows I respect the crap out of him. It happens to EVERYONE if you build enough.


May I request pictures of the total amp and then detailed pics of the "bad" unit?
 
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