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Old 12th April 2009, 03:57 PM   #1601
RCruz is offline RCruz  Switzerland
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Hi Salas

Found the issue... I am sorry to report I placed some 6k8 in R1 instead of 6.8r

Now it is steady as a rock and very warm (100șC).

I will implement it today and report the differences.

Ricardo

PS:
I read you have a capacitor-less B1... I am very interested... Would you care to share the idea ?
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Old 12th April 2009, 05:49 PM   #1602
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Default 2nd shunt installed !!!

Noticeable gains in transient speed and attack.

Bigger image and better focused and tighter bass.

All this using only one bridge before a 10.000uF cap.!!!

This Riaa design really benefits from a good psu.

Next will be the double bridge + cap setup.

PS: I rolled back from the output cap bypass (The teflon gave enourmous extension in bass but also in the trebble and I found it too much for the actual setup)

Ricardo
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Old 12th April 2009, 06:44 PM   #1603
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After 1 hour burning..... incredible instrument placement and diferentiation. Deeper sounstage.

Working in the CDP, I learned that best results are obtained by placing 1 reg near each power v-in of each chip so now I have 11 regs in the CDP (several chips have more than 1 reg). Each one gave enourmous gains.

It seems here we have a similar situation. (But incomparably superior results)

Ricardo

One mod a day keeps the doctor away....
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Old 12th April 2009, 09:07 PM   #1604
Salas is online now Salas  Greece
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Nice Ricardo. I have experienced similar gains in Michael's double PSU one that I have shown here before. I would suggest you make an experiment about cutting on dissipation a little and see if your sound is still the same. Try to listen with 8R2 and 10R shunt's R1 at a point.
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Old 12th April 2009, 10:08 PM   #1605
Salas is online now Salas  Greece
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Quote:
Originally posted by RCruz
PS:
I read you have a capacitor-less B1... I am very interested... Would you care to share the idea ?
Its in the main B1 thread.

Its revised schematic is there too.
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Old 13th April 2009, 11:20 AM   #1606
RCruz is offline RCruz  Switzerland
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Thank you for the tip Salas.

Altered R1 value to 14ohm and now I have 185mA ICSS shunt "b" and 206mA ICSS Shunt "a".

Temperature droped to 46~50șC

Sound is perfect as is.

Next will be the dedicated bridge for shunt "b".
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Old 13th April 2009, 02:04 PM   #1607
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I am noticing an unwanted increase in hum... right channel... now powered by the new shunt "b" coloured brown.

There is a lower freq noise in this channel (it is buried beneath the surface disc noise but audible when the pickup is not lowered)

The other channel also produces noise but not so audible in low freq.

Seems to me I have a placement issue.... must I build a gnd screen between the shunt and riaa boards ?
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Old 13th April 2009, 02:20 PM   #1608
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If you change the connections and power the other channel, does the hum migrate? Can it be a wiring issue?
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Old 13th April 2009, 04:20 PM   #1609
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I did not try that yet...

Do you believe a metal shield between shunt and riaa should improve matters ?
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Old 13th April 2009, 05:47 PM   #1610
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Can't tell if the problem is a field or a loop until you know. If its a field, yes, a metal shield will help. Move it to the right to test.
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