Phono stage

Switch the extra 6db in - it improves pace and drive.

The psu rebuild would do it!

Yup it was good.
 
Why would changing the PSU alter the units ability to drive a certain load? Surely as long as the active parts have enough juice to work fully... WAD suggested a cap in the PSU to make it drive TVC's so you could be right. Rob said he didn't have that in there though!
 
Tenson said:
Why would changing the PSU alter the units ability to drive a certain load? Surely as long as the active parts have enough juice to work fully... WAD suggested a cap in the PSU to make it drive TVC's so you could be right. Rob said he didn't have that in there though!
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I thought about this yesterday and there are three possibilities:

1 - All the PSU caps were replaced with Black Gates which have a different spec to the original caps and are slighly higher capacitance.

2 - We were facing magnetic north at the time of the test or perhaps the iron in all that Guinness we drank was having an effect on the field in the room ?? ;)

3 - As we thought on Saturday, perhaps the input impedance of the Bryston active x-overs was lowish and somehow reflecting back through the S&Bs ??

I think it's likely to be a combination of 1 & 2
 
RobHolt said:
I thought about this yesterday and there are three possibilities:

1 - All the PSU caps were replaced with Black Gates which have a different spec to the original caps and are slighly higher capacitance.
Click to expand...

Hmm how does that change its ability to drive a load though? I mean it could provide a little more current but that is not going to make the difference between motorboating and working perfectly, is it?
 
Tenson said:
Hmm how does that change its ability to drive a load though? I mean it could provide a little more current but that is not going to make the difference between motorboating and working perfectly, is it?
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Something to do with "problems due to common impedance coupling on the HT line" - but that explanation makes my brain hurt so I will ask the WD boys to elaborate.
 
murray johnson said:
Rings less like that as well! :D
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Not really because you will just switch it to a lower setting to compensate. Besides, you can't ring less than not at all ;)
 
That's exactly what I was thinking. There will be less attenuation without the extra 6db at the same volume level.
 
At the same volume level the attenuation must be the same.
How it's done is different though.

Tenson, I'm not sure everyone who's listened to an S&B TVC would agree with you but if you're happy with it that's all that really matters.
 
murray johnson said:
At the same volume level the attenuation must be the same.
How it's done is different though.

Tenson, I'm not sure everyone who's listened to an S&B TVC would agree with you but if you're happy with it that's all that really matters.
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First part, true, I forgot it uses the primary coil differently in 6dB mode.

Second part, I don't mind if they don't like them, but they don't ring one bit unless you use them out of bandwidth (above 40KHz). That could happen with a TT but is easily fixed with a filter at 20KHz.
 
Tenson said:
F That could happen with a TT but is easily fixed with a filter at 20KHz.
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Isn't that filter likely to result in ringing in the audible frequesncy range?

What filters are used in nature?
 
Stereo Mic said:
Isn't that filter likely to result in ringing in the audible frequesncy range?
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Maybe, perhaps a filter a bit higher up would be better. Even so, I suspect a filter would ring less than the transformers when used out of bandwidth, especially if excited by cutter resonances which already ring quite badly. At line level you have the option of quite a few different types of filters as well. But then again, if you are using a TT you are not necessarily going after technical accuracy anyway.
 
Well after a false start with some silver mica caps (sounded god-awful) - I am now using some polys - seems to be fine. I am awaiting your contribution tenson ... what about a day next week (except wednesday?)?
 
brizonbiovizier said:
Well after a false start with some silver mica caps (sounded god-awful) - I am now using some polys - seems to be fine. I am awaiting your contribution tenson ... what about a day next week (except wednesday?)?
Click to expand...

To re-jig the crossovers and DRC? I should be able to do it next week. How is Sunday coming? Or I can do a weekday if you would rather.
 
brizonbiovizier said:
Well after a false start with some silver mica caps (sounded god-awful) - I am now using some polys - seems to be fine. I am awaiting your contribution tenson ... what about a day next week (except wednesday?)?
Click to expand...

Where did you put the SMs?

I have them in my phono stage and they sound superb (you've heard it).

Confused :confused:
 

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