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Old 18th March 2013, 07:06 PM   #171
bcmbob is offline bcmbob  United States
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At the time I bought those caps I was unfortunately involved (never again ) in one of those circular disputes about changes in cap performance over time. I believe I was tuned in to whether what I heard was in my ear or in my mind - playing tricks with my brain I'll just say the qualities I perceived were as valid as any other comparisons made. The overall sound of the RC builds has sweetened over the months since the BG Fs were installed. Don't know what if anything might happen with extended use.

Along with several other elements, I plan to do a bit of the "Swap and Twirl" dance on the final boards during that build. I have the confidence to buy those caps again but am just as interested in auditioning any other option developed here on the thread.

P.S. You almost lost me Saturday evening! After listening to every track on this CD - twice, The FEs and the Sunflowers had me ready to find St. Peter and join the jam session. Quincy usually over-records, but the FEs accurately reproduced everything from room shaking bottom synths and timpani , tiny bells, massive group vocals and instant dynamic reversals. Gonna go play it again when I finish this note

Dario, you've created a monster amp !!
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Last edited by bcmbob; 18th March 2013 at 07:21 PM.
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Old 18th March 2013, 08:00 PM   #172
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Default More on C9 voltage rating

Jac, what you described apply on normal working conditions but C9, in theory, can be exposed to full rail voltage (35V) in case of failure.

It's for this reason that I suggest to mount them only after positive tests on modules and to keep some spares in case of problems.

In a properly used and heatsinked working build it's very unlikey that those little PKs will ever have any problems.
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Old 18th March 2013, 08:37 PM   #173
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Quote:
Originally Posted by ClaveFremen View Post
Jac, what you described apply on normal working conditions but C9, in theory, can be exposed to full rail voltage (35V) in case of failure.

It's for this reason that I suggest to mount them only after positive tests on modules and to keep some spares in case of problems.

In a properly used and heatsinked working build it's very unlikey that those little PKs will ever have any problems.
I totally agree. So far, I have used lesser, higher voltage caps to prove the build before installing anything low voltage. As long as I think slowly, I will do the same on these builds.
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Old 18th March 2013, 08:51 PM   #174
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Red face Faston Connections at the Speaker In and Out

Although I know that Tom and others prefer never to use Faston's or disconnect terminals, it is the "normal" way to attach the speaker wires to a MyRef. I've been looking around for alternatives that are better materials without going crazy with the Furutech/WBT expensive alternatives. I found these industrial parts from Mouser that might work.

This is a case of flipping the connection. It uses a female board mount made from brass with a tin over copper plating. If you look at the Mouser page, you won't see what you are getting. Look at the Data Sheet.

1217080-1 TE Connectivity / AMP | Mouser

Once you get the female on the board, these are two sizes of copper, male wire mount disconnects. The small one (18-22 AWG) is gold plated copper. The bigger one (10-12 AWG) is also available in other wire sizes and is tin plated copper. Again, be careful by reading the data sheets. Some of these are mis-specified as copper when the data sheet shows brass.

19022-0004 Molex | Mouser

19004-0012 Molex | Mouser

In the end, these are a pretty low cost alternative.
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Old 18th March 2013, 08:57 PM   #175
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Quote:
Originally Posted by lehmanhill View Post
In the end, these are a pretty low cost alternative.
I would, instead, use the holes for bare wire no cost at all and best result...

Click the image to open in full size.
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Old 18th March 2013, 09:12 PM   #176
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Quote:
Originally Posted by bcmbob View Post
.... the FEs accurately reproduced everything from room shaking bottom synths and timpani , tiny bells, massive group vocals and instant dynamic reversals. Gonna go play it again when I finish this note

Dario, you've created a monster amp !!
Yep. These amps sound absolutely great! The only problem is that I now have an image of Bob dancing around his living room stuck in my mind.

Jac
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Old 18th March 2013, 09:14 PM   #177
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Quote:
Originally Posted by ClaveFremen View Post
I would, instead, use the holes for bare wire no cost at all and best result...

Click the image to open in full size.
Even better!

Any idea what wire gauge will fit in the hole?
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Old 18th March 2013, 09:26 PM   #178
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Quote:
Originally Posted by lehmanhill View Post
Any idea what wire gauge will fit in the hole?
Drill is 2.2 mm / 0,0866 in, should be AWG12

Alternate better connectors (yet to be tested for fit):

571-216843-1 (Phosphor bronze faston male PCB Connector)
571-42437-5 (Phosphor bronze faston female connector)
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Last edited by ClaveFremen; 18th March 2013 at 09:29 PM.
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Old 18th March 2013, 09:27 PM   #179
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Quote:
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Any idea what wire gauge will fit in the hole?
Never mind, I can answer my own question. It looks like 13 gauge stranded, maybe 12 gauge if you push it.

Jac
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Old 18th March 2013, 10:58 PM   #180
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Perhaps I was harsh in my condemnation of parts from Taiwan. Could there possibly be one honest person there selling the last of the world's supply? Yes, they are very enterprising, and counterfeiting could be a lucrative occupation. Is there any definitive test of legitimacy? If you guys are happy with them, perception is everything.

Jac, thanks for the explanation of the circuit. Now I understand the function of C9 and the other parts there. As you all have proven, if the amp functions properly, low voltage parts are adequate. Carry on.

If C9 functions as a high pass, its value establishes the corner. Is it supposed to affect subsonic frequencies or merely block DC? If subsonic, how low is too low? Dario, what differences did you notice between 220uF and 470uF? Perhaps as Andrew T maintained all along, that really is the limiting factor for bass output of the MyRef. In that case, what hazards would a larger value pose to performance of the amp? Would there be any negative sonic impact? Does anyone use value other than 220uF, and what does that do to the bass?

Peace,
Tom E
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