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Old 12th March 2011, 03:14 AM   #11
konga is offline konga  United States
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Took off the tube guard and swapped in a pair of NOS RCA 6F8G tubes on adapters.

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Old 14th March 2011, 01:24 PM   #12
Bernie7 is offline Bernie7  Singapore
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I have a CD3 with Grepin CV181 tubes. Am considering changing the caps too.

Are those 6 blue caps in the signal path or just power rail decoupling caps?
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Old 15th March 2011, 09:22 PM   #13
konga is offline konga  United States
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Bernie7: How do those Grepin CV181 sound? They look every festive! I believe all 6 blue caps are in the signal path. Looking at the board traces they are in both the plate and the grid pins. The thick blue wire looks to be the heater circuit and black Nichions are the power caps. After a few search it looks like everyone changes the blue caps and leaves the black Nichions alone.

I just ordered some NOS Sprague "Vitamin Q" 400V paper in oil caps and will be putting them in when they arrive. Hopefully they will sound decent, otherwise the ClarityCaps are cheap and I may switch over to them.
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Old 16th March 2011, 12:14 AM   #14
Bernie7 is offline Bernie7  Singapore
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Default Swap 0.47uF for 0.22uF?

Quote:
Originally Posted by konga View Post
Bernie7: How do those Grepin CV181 sound? They look every festive! I believe all 6 blue caps are in the signal path. Looking at the board traces they are in both the plate and the grid pins. The thick blue wire looks to be the heater circuit and black Nichions are the power caps. After a few search it looks like everyone changes the blue caps and leaves the black Nichions alone.

I just ordered some NOS Sprague "Vitamin Q" 400V paper in oil caps and will be putting them in when they arrive. Hopefully they will sound decent, otherwise the ClarityCaps are cheap and I may switch over to them.
Grepin CV181 is festive looking and sound like it too being much better than the stock tubes, more open and airy sounding. I haven't tried other tubes.

Think I'll begin by swapping the blue caps with Dayton 0.47uf 400V caps that I have. These are cheap and pretty good sounding. Any idea if swapping 0.47uF for the 0.22uF pair is a no-no? If these are in the signal path I would think there's no harm.
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Old 16th March 2011, 06:12 AM   #15
singa is offline singa  Singapore
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Quote:
Think I'll begin by swapping the blue caps with Dayton 0.47uf 400V caps that I have. These are cheap and pretty good sounding. Any idea if swapping 0.47uF for the 0.22uF pair is a no-no? If these are in the signal path I would think there's no harm.
Hi,
Because capacity is doubled you have a lower low frequency extension
so you will hear more bass which is better. singa

PS there is no necessity to change the 4 power decoupling caps as it will
not have a significant improvement or none at all.A upgrade to mundorf
silver/gold or silver/gold in oil or at least silver in oil will be worth your while.
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Old 17th March 2011, 12:31 AM   #16
Bernie7 is offline Bernie7  Singapore
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Quote:
Originally Posted by singa View Post
Hi,
Because capacity is doubled you have a lower low frequency extension
so you will hear more bass which is better. singa

PS there is no necessity to change the 4 power decoupling caps as it will
not have a significant improvement or none at all.A upgrade to mundorf
silver/gold or silver/gold in oil or at least silver in oil will be worth your while.
Thanks for the input singa

I did change the four .47uf caps earlier to Dayton and imo there was a noticeable improvement to the sound, seems clearer and more detailed. Will try the ultimate, ie mundorf one day, right now having fun rolling caps
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Old 21st March 2011, 12:35 AM   #17
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Quote:
Originally Posted by konga View Post
Barbieboy do you have a multimeter? Can you measure the heater voltage and current (blue wire).
Hi Konga, still not got my multimeter back from lending it out, sorry about that, perhaps someone else can measure for you.
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Old 21st March 2011, 12:53 AM   #18
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Ok got round to replacing all six caps under the hood (4x0.47uf and 2x0.22uf). Opted for ClarityCap SA's because they are a known quantity, not expensive and they fit ! Substantial improvements all round. Only run in some 8 hours and notice far more detail in the mid, plucking guitar strings and voice's re-verb are now there and tactile, bass has more extension, nothing new in the highs, but they are still not burnt in yet.

All in all very worthwhile, no going back.

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Old 26th March 2011, 12:23 AM   #19
konga is offline konga  United States
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Re-Capped with NOS Sprague Vitamin Q's. My experiences echo BarbieBoy's! This should be a must do mod! Going to wait until they burn in completely before do a final report on sound. I thought they would be very warm and romantic being a old PIO cap but they are surprisingly clean and clear sounding with great extension.

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Old 30th August 2011, 04:10 PM   #20
konga is offline konga  United States
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Just wanted to update this thread and say that I've been enjoying this little Yaqin buffer immensely hooked up between my Squeezebox touch and vintage Marantz.

However sometimes I think the gain is a little on the high side. Anyone have any idea how to adjust the gain on this unit? I see several resisters on the board and wonder what would happen if I changed the values.

Also I'm playing with the idea of increasing the input capacitors, the 2 .22uf ones near the front of the unit. I've read that may increase bass response.

Any suggestions?
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