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Old 21st October 2012, 11:32 PM   #4071
Reality first!
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Quote:
Originally Posted by bismuth View Post
I've checked, rechecked, unsoldered/resoldered, changed RC capacitors and... now I've got a much nicer square wave response over the audio band !
Fine

But what you did to obtain it?

Quote:
Originally Posted by bismuth View Post
I've a 100nf MKS2 for C7, what is the effect of lowering it to 10nF FKP ?
The point is not the value but the quality of the cap.

Sadly film/foil caps in 5mm LS are 33nF max.
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Old 22nd October 2012, 06:23 AM   #4072
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Quote:
Originally Posted by bismuth View Post
... now I've got a much nicer square wave response over the audio band !

Thank you very much for your help.

I've a 100nf MKS2 for C7, what is the effect of lowering it to 10nF FKP ?
You're welcome - please post the key changes, if any, to achieve the square wave response.

The effect of the foil cap at C7 is tighter definition and imaging. The lower value also increases the self-resonant frequency with the track inductance about 3x, putting it well outside the audio band.
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Old 22nd October 2012, 07:32 AM   #4073
soongsc is offline soongsc  Taiwan
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Quote:
Originally Posted by ClaveFremen View Post
Fine

...



The point is not the value but the quality of the cap.

Sadly film/foil caps in 5mm LS are 33nF max.
I have some 470nF
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Old 22nd October 2012, 07:34 AM   #4074
bismuth is offline bismuth  France
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Hi,
Sorry to disappoint, I do not know exactly what was the culprit. No special discover here, I guess I just messed up a C value. Or perhaps a bad solder, or a bad component, but I doubt since my two mono-blocks behaved the same. I didn't measured the capacitance of the replaced capacitors.

Short listening session on a real speaker last night in mono, it sounds fine to me, and I noticed very clean and tight bass. I remember from previous Gainclone of changes during the first hours, is there a "burn-in" time recommended with the MyRef before playing with component swap ? I plan to change C7 as recommended on one monoblock to compare.

Thanks again, your support gave me the motivation to sort this out and finish this project, I'm sure the boards will otherwise have stay 6 month longer on a corner of the bench...
Time for metal work, maybe a finished amp in 6 months ...
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Old 22nd October 2012, 10:30 AM   #4075
johnm is offline johnm  United Kingdom
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Quote:
Originally Posted by linuxguru View Post
You're welcome - please post the key changes, if any, to achieve the square wave response.

The effect of the foil cap at C7 is tighter definition and imaging. The lower value also increases the self-resonant frequency with the track inductance about 3x, putting it well outside the audio band.
Sorry for the off topic post linuxguru, but I've tried e-mailing you, and have also sent a private message via this site, with no response to either, and yet you've been online... I paid for my kit on the 26th September and have yet to receive anything. Have you sent it out yet please?

Thank you.

John.
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Old 23rd October 2012, 11:19 AM   #4076
johnm is offline johnm  United Kingdom
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Linuxguru: could you please respond to my PM - according to your profile details here you've been online both yesterday and this morning...

Have you shipped my MyRef parts out yet please that I paid for on the 26th September?

Thank you.

John.
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Old 23rd October 2012, 04:07 PM   #4077
johnm is offline johnm  United Kingdom
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Thanks for the full refund for the kit, which was never sent out.

In the future, might be best to keep future buyers of your kits informed if there's going to be a delay though

Thanks again.

John.
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Old 23rd October 2012, 05:00 PM   #4078
AndrewT is offline AndrewT  Scotland
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Communication is essential.
Delays can happen.
But, do keep the customer informed.
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Old 18th December 2012, 12:27 PM   #4079
catalin is offline catalin  Romania
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Quote:
Originally Posted by soongsc View Post
MyRef C Caddock R3 with LM3886 grounded at power GND
Click the image to open in full size.

MyRef Dario Caddock R3 old C32 value
Click the image to open in full size.

Isn't it interesting?
Sorry ,can someone explain what these graphs is showing ?
How the graphs are done and how is the measurement done ?
Thank you !
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Old 18th December 2012, 03:12 PM   #4080
udailey is offline udailey  United States
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