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Old 17th March 2013, 11:54 AM   #2261
Bibio is offline Bibio  Scotland
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i'll stick with my original statement but add that B has very rolled off highs and might account for less surface noise. i just feel A has ever so slightly more bite/grip/air.

i like both and would be happy with either.
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Old 17th March 2013, 01:03 PM   #2262
kor952 is offline kor952  Netherlands
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Forget what I did write earlier...
A and B are both from the same record. A is slightly more dynamic, has a little more bite/grip/air as Bibio describes.
Could it be the difference between signal in or out fase (both channels).

Ronald.
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Old 17th March 2013, 03:44 PM   #2263
vulejov is offline vulejov  Serbia
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Same record, same cartridge and turntable.. maybe different electronics, B file sounds little better..
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Old 17th March 2013, 04:22 PM   #2264
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A sounds like it has a little more treble, more open. I concur with the fact that the highs in B are more rolled of. I personally like A more.
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Old 17th March 2013, 11:32 PM   #2265
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I still think B seems compressed.
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Old 18th March 2013, 12:21 AM   #2266
rjm is offline rjm  Japan
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A is a Marantz SR220

B is a VSPS300, user supplied parts, not the kit.

A measure of the frequency response delta was obtained by taking nominally identical 1s clips from each recording and taking the difference in the FFT data.

As most of you observed the Marantz has a +2 dB lift of the treble frequencies centered at 10 kHz. It sounds more lively and open, and surface noise is more prominent. The VSPS300 actually has a greater response above 10 kHz though, partly because of the 4th time constant built in to the RIAA eq., and partly because the Marantz rolls off the extreme treble.

The VSPS300 will be perceived to have stronger bass response. I also think it has better stereo separation.

The recording was made when the VSPS had had barely 3-4h of burn in time. Part of the reason it sounds "congested" (and I concur with that assessment) can be put down to the electrolytics not having had sufficient break in time. The rest would come to the treble lift of the Marantz.

For the record, I'm actually quite impressed with the Marantz, it sounds nice. On closer evaluation though I felt it was perhaps a bit harsh and I came to prefer the smoother, more rhythmic drive of the VSPS. I was never doing this blind though: I always knew which was which. It's far harder to pick out differences when you have no idea where to start. You guys are good!

I double-checked the VSPS circuit in LTSpice and indeed the response accurately follows the RIAA+AW response curve to <0.5 dB with the standard BOM parts. Even allowing 5% tolerance in the RIAA cap values, it cannot move 2 dB. So the response error (barring something really odd in that particular VSPS build) is on the side of the Marantz. It might have been a mistake, but it might just as likely have been designed to sound that way.
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File Type: png Frequency Response.png (20.2 KB, 124 views)
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Last edited by rjm; 18th March 2013 at 12:36 AM.
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Old 18th March 2013, 01:24 AM   #2267
rjm is offline rjm  Japan
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Default VSPS300 simulated frequency response (BOM)

LTSpice simulation, output compared to standard RIAA curve.
Attached Images
File Type: jpg VSPS300 test excel.jpg (117.9 KB, 126 views)
File Type: jpg VSPS300 test response.jpg (29.1 KB, 120 views)
File Type: jpg VSPS300 test.jpg (49.2 KB, 126 views)
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Old 18th March 2013, 01:27 AM   #2268
Bibio is offline Bibio  Scotland
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hhhmmm i must have cheep ears :-)

as a side note, what TT and Cartridge were used?
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Old 18th March 2013, 02:29 AM   #2269
rjm is offline rjm  Japan
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Not really. You heard what I heard, you just choose to put a slightly more positive spin on sound of the Marantz. Which is anyway far from bad, I think.

I don't know the details of the upstream components. One detail I forgot to mention earlier is the VSPS300 was built using NE5534 op amps rather than OPA27.
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Old 18th March 2013, 04:05 AM   #2270
rjm is offline rjm  Japan
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Background story to this:

I get a distress call, as I often do. This time, someone wanted to know if there was a problem with their VSPS300 (my boards, their parts, NE5534 and NOS Russian caps) as it appeared to sound rolled off in the treble.

The first set of audio files I was sent, the Marantz seemed bright and lively where the VSPS was indeed rolled off, or at least "odd" in the treble response. I admit I preferred the Marantz.

After confirming that the RIAA values were correct, and changing the caps C1-3 to no particular effect, we discovered that some resistors in the X-reg were incorrect leading to the V+,V- voltage to the opamps being only +/-3.5 V. This is within the datasheet operating limits for the NE5534, but far from ideal.

The VSPS300 with the X-reg repaired (the file you all heard) sounded better but not, I would say, fundamentally different in response. Just that the sense of drive was restored, with more energy across all frequencies. I switched my preference and declared that his VSPS300 was now working according to specification, suggesting the apparent suckout in the treble was most likely an artifact of using the Marantz as a reference. My hope is that the residual congestion will fade out after 48h or so burn in. In my experience, it usually does.

I trust my ears, but it was pretty subtle and I did I suppose have a vested interest in the outcome. Long and short of it is I decided to put it to an objective test. Google Drive makes this convenient. I would be nice if more people posted high quality recordings of their analog setup, I think it would be both fun and useful...
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