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Puffin: dB Gain to Voltage Calculation?

Soniclife

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Update on going SUT-less:

Warning: I'm about to delve into subjective foo foo.

Noise aside, my subjective impression is that, without the SUT in the picture, the ART-7 straight into the Puffin lacks macro-dynamic capacity.

It's perplexing, as I can hear very soft sounds and detail is good.

But the loud passages don't seem as loud as they should be.

They don't sound like they're clipping, just a bit flat, as if double fortes are single fortes.

I can think of two semi-plausible explanations:

1. It's a subjective normalization problem -- because I can hear lower-level details, I'm able to listen at lower level volumes, and thus just not using as much master volume gain as I normally would.

2. 68 dB of gain on the Puffin is still too close to its max gain of 72 dB, and may be lacking headroom.

As an aside, the Puffin documentation refers to supporting MC carts in the 0.25mV range, and the ART-7 is half that....

Any thoughts from the academy?
Check replay levels, you're probably playing quieter.
It could be lower distortion on the peaks, or a difference in frequency response between the carts.
 

MRC01

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Thanks, although given the Puffin is a very different device, I'm not sure what to make of your findings vis-a-vis the Puffin. ... Which I guess would argue for running the Puffin at 60 dB gain (72 - 12)?
I'm suggesting to try different gain settings, especially lower ones. I got good results from a lot less gain than appeared necessary on paper. Take the numbers on paper as a starting point but also experiment outside the lines. "the more gain, the more pain" especially as you approach the upper limits. From what I read, the Puffin is unique, applying RIAA in DSP, but it has a conventional gain stage so some of the standard rules may still apply.

... The cartridge in question is a new (maybe 7 hours of use so far) ... But I don't know if ASR believes in cartridge break-in.
Cartridges are mechanical so break-in is more of a possibility than it would be with electronics. Especially as they rely on balancing tension & compliance and the elastomers may change with usage & time. Shure says break-in takes about 2 weeks. But lots of companies say this because phono cartridges sound quite different and they know takes time to get used to a different sound. So whether this is break-in of our perceptions and expectations, or the cartridge elastomers following a Pareto-like curve toward "nominal", is a subject for debate.
 

MRC01

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... It could be lower distortion on the peaks, or a difference in frequency response between the carts.
+1 to that. Distortion even at barely perceptible levels (say 1%) is a perceptual cue for "loudness". At some time along our audiophile histories, most of us have had the experience of a super clean low distortion audio system playing louder than we realize, because the loudness cue of distortion was missing.

PS: I never experienced big clean effortless natural sounding dynamics until digital audio came along. Analog recordings, even good ones, have tell-tale cues as analog tape has increasing distortion and compression before actual saturation occurs. Some recording engineers consider this desirable or euphonic so they record a bit on the "hot" side. For example I hear this in many of Pierre Sprey's Mapleshade recordings.
 
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watchnerd

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Check replay levels, you're probably playing quieter.
It could be lower distortion on the peaks, or a difference in frequency response between the carts.

Checked with SPL meter.

Was about 5-10 dB below normal.

Which is probably a testament to the cart's ability to resolve low-level detail.

Maybe there is something to those non-magnetic cores...
 
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watchnerd

watchnerd

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I'm suggesting to try different gain settings, especially lower ones. I got good results from a lot less gain than appeared necessary on paper. Take the numbers on paper as a starting point but also experiment outside the lines. "the more gain, the more pain" especially as you approach the upper limits. From what I read, the Puffin is unique, applying RIAA in DSP, but it has a conventional gain stage so some of the standard rules may still apply.

There may be some wisdom in this line of thinking.

According to this, even for low 0.25 MCs, the suggested gain is 64 db:

http://parksaudiollc.com/cartridges.jpg

I did an on-the-fly adjustment, cranking the Puffin down to 64 dB gain, and setting the Devialet to 0.5V input.

I swear it sounds more full-bodied, but, of course, I may be imagining things.
 

MRC01

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For subjective comparisons, the dynamic extremes are useful. Compare noise (low level hum or hiss) and resolution in the very quietest passages, and compare how clean and undistorted are the loudest crescendos or peaks.
 
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watchnerd

watchnerd

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Just got another cartridge to try it with.

AT33/SA

A more normal 0.4mV output, a magnetic core, and Shibata stylus.

I've kept the Puffin gain the same at 64 dB, per recommendations for AT cartridges, but increased the Devialet line-in input to 0.7V.
 

BDWoody

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Just got another cartridge to try it with.

AT33/SA

A more normal 0.4mV output, a magnetic core, and Shibata stylus.

I've kept the Puffin gain the same at 64 dB, per recommendations for AT cartridges, but increased the Devialet line-in input to 0.7V.

How are you finding the puffin? Feel free to do the digital out mod should you choose...
 
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watchnerd

watchnerd

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How are you finding the puffin? Feel free to do the digital out mod should you choose...

After listening for several weeks now, and across two different cartridges, I've come to the conclusion that the Puffin + Devialet (line in) is not transparent to going straight into the Devialet (phono).

This is even with the alleged loadings set to be the same in both cases (200 ohm).

I'll leave my subjective impressions out of it for now lest I introduce bias.

Hopefully will have some time to make some rips over July 4 weekend.
 

MichaelP

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Perhaps this was discussed already. Have you tried dialing in your Puffin using the levels display. It can display average and peak values. Turn the dial until you see the A / D display, it's the last ones. Hit the button to put it into peak monitoring mode. You're clipping if those peaks hit zero on either the analog of digital side. Turn up or down the gain to find a level that is just below clipping.
 

audiopile

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Oddly enough -I've been running a even lower output cart (very old Ortofons that put out .07 mV or .09mV ) at the 56dB gain/200 ohm MC loading. This is going out SPDIF directly into one of my SPDIF inputs on some old Meridian DSP-5000 speakers (24/96 out of Puffin -into the Meridians), Without using the appropriate Ortofon STM-72 SUT-EVERY other phono preamp I've got here has some hiss if old Ortofons are fed directly into it's MC stage -not necessarily obnoxiously hissie -but clearly there. The Puffin digi to Meridian is entirely acceptable in terms of noise and I do turn the Meridian up a bit more to listen (+15 or so on the Meridians display) -but that's what a volume control is for. So carts with very very low output -very low coil resistance (2-3 ohms) -designed to be run into less than 10 ohm SUT with very high gain - frankly surprised and pleased that 200 ohm input at 56dB seems to work and work well ?
 
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