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Old 22nd September 2013, 04:50 PM   #141
PKI is offline PKI  United States
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Just finished my Pearl II. I have some oscillations +/- 30mV of DC offset before the cap and ~5mV on the output(maybe my DMM). I removed C7, with it oscillations were ~+/- 100mV. It is dead quiet with my F6, sounds quite lovely. However, it is not enough gain with my Denon DL-301, I have to turn B1 all the way up to reach normal level. Should I check something else to eliminate these oscillations?
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Old 22nd September 2013, 05:36 PM   #142
PKI is offline PKI  United States
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Ok, so it looks like I have problems similar to discussed above: drifting DC offset and terrible hi-freq hiss when I play music. So what was the solution? Dead 3310? Hm, that would be strange. It works and make sound with the dead transistor? Both channels? It's very annoying. This sound not just mental trust me!
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Old 22nd September 2013, 05:55 PM   #143
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Ok, so it looks like I have problems similar to discussed above: drifting DC offset and terrible hi-freq hiss when I play music. So what was the solution? Dead 3310? Hm, that would be strange. It works and make sound with the dead transistor? Both channels? It's very annoying. This sound not just mental trust me!
30mv oscillation is normal. As for the gain, if you built it stock, you need to bump it up to work with a LOMC cartridge.

As for the noise, check out this post. The Pearl 2 needs a "zobel" network on the input with certain high-inductance cartridges.

Strange problem with Pearl 2 and SAE Cartridge
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Old 22nd September 2013, 08:04 PM   #144
PKI is offline PKI  United States
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Thanks!
Gain: I added another 1k on the top of the R14. That gives me 500R instead of 300 recommended for LOMC. What do you thing gainwise: normal listening level should be at 3 o'clock of volume knob, right. Just not to add more gain in Pearl ll than needed. What do you think about it?

Zobel: does it change sound overall or just compensate ringing? How important is the component quality in there?
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Old 22nd September 2013, 08:21 PM   #145
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Thanks!
Gain: I added another 1k on the top of the R14. That gives me 500R instead of 300 recommended for LOMC. What do you thing gainwise: normal listening level should be at 3 o'clock of volume knob, right. Just not to add more gain in Pearl ll than needed. What do you think about it?

Zobel: does it change sound overall or just compensate ringing? How important is the component quality in there?
3 o'clock is pretty high. I'd go higher with R14.

I don't know what type of components to use for the Zobel, 6L6 actually gave them to me.
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Old 22nd September 2013, 09:59 PM   #146
Mr. dB is offline Mr. dB  United States
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However, it is not enough gain with my Denon DL-301, I have to turn B1 all the way up to reach normal level.
How much gain does the F6 have? It's not a unity gain amp like the F4 is it?
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Old 22nd September 2013, 10:27 PM   #147
PKI is offline PKI  United States
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Should be ~15db.
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Old 25th September 2013, 02:38 PM   #148
Gooch is offline Gooch  United States
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Very nice work PKI
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Old 25th September 2013, 02:45 PM   #149
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Thanks! The only one thing I do not like: it gives such a big pulse into my speakers after you turn it on so the woofers are about to jump out. Does some one have the same thing? Being more specific offset jumps up to 7v when you turn it on and then falls to 70mV. And start drifting...
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Old 25th September 2013, 05:27 PM   #150
6L6 is offline 6L6  United States
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Zobel: does it change sound overall or just compensate ringing? How important is the component quality in there?
I believe Wayne mentioned that he is putting the zoble in all the Pass Labs phono stages... So don't worry about it .
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