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Peavey USB-P Review (Balanced DAC)

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amirm

amirm

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Can’t you just use a dongle for this sort of thing? Even the Apple dongle has 96 SINAD
Dongle doesn't provide isolation and can easily create ground loops given the long runs in sound reinforcement field. It is also extremely fragile so definitely not a fit for this use.
 

GDK

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It is from the book, "Bread in half the time," page 153 with the title of, "rich dinner rolls in an hour." It is by Linda West Eckhardt and Diana Collingwood Butts.
Ordered. Thank you!
 

Addicted to music

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@amirm

i can smell those bread rolls from here....and when that happens I can devour the whole lot in minutes.... no words can describe that photos.....mmmmmm yum!

Happy Thanksgiving and stay safe.
 

AudioTodd

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Not surprised. Transformers of any useful quality would blow the BOM of this totally out of the water. Transformers are something there is no Moore's Law for, and they just get more expensive over time. I think that if you need galvanic isolation you are going to have to bite the bullet. Either take the hit on distortion, or accept that there is a serious whack going onto the BOM, and a commensurate impost onto the retail.
In reality this level of distortion isn't historically all that bad. It is just that we now reasonably expect much better.
Indeed. If you really, really need it, maybe get a Jensen transformer isolator. Many claim they are as good as they come or come in second. In any case, you can always use it in another setup down the road if your system changes. They are not cheap, but being able to keep it long term for multiple uses makes it not such a bad deal. And I find them transparent even without doing blind tests.
 

milosz

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Such low output and high THD- I am guessing that the output transformers used in this thing are small and easily saturable, which isn't surprising given the price point.

Substituting a nice Jensen transformer for this BOM wouldn't work. You can't feed digital audio over USB and get analog out from a Jensen transformer; this BOM is a D/A converter after all, not just an isolation transformer.

Instead of using this gizmo, you could use a USB isolator on the input of your good quality balanced-out DAC to break the ground loop. Or use optical SPDIF into your DAC. Both approaches are less expensive than using Jensen transformers on the output of your DAC to eliminate ground loop issues.

I hate ground loops.
 
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AudioTodd

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Such low output and high THD- I am guessing that the output transformers used in this thing are small and easily saturable, which isn't surprising given the price point.

Substituting a nice Jensen transformer for this BOM wouldn't work. You can't feed digital audio over USB and get analog out from a Jensen transformer; this BOM is a D/A converter after all, not just an isolation transformer.

Instead of using this gizmo, you could use a USB isolator on the input of your good quality balanced-out DAC to break the ground loop. Or use optical SPDIF into your DAC. Both approaches are less expensive than using Jensen transformers on the output of your DAC to eliminate ground loop issues.

I hate ground loops.
DUH. My point was if you have a problem with ground loops in your PC-based system, etc. and buy this inexpensive DAC to cure those because of the transformers, you would probably be better off, provided you can afford it, to use your existing balanced or single ended DAC and add an appropriate Jensen isolation transformer after the DAC. I have two Jensen PC-2XRs for various configurations and think they sound indistinguishable from a level matched bypass from a few different “pretty” high end DACs (Benchmark DAC3 B and HGC, Auralic Vega and Schiit Modius directly tested). You would always have the Jensen if you wanted a better DAC later and still had ground loop problems.
 
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Jensen PC-2XR
Jensen provides nice distortion measurements for their transformers:
1606526967058.png


Low frequencies as expected are the enemy of transformers.
 

AudioTodd

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Jensen provides nice distortion measurements for their transformers:
View attachment 96218

Low frequencies as expected are the enemy of transformers.
Indeed. I keep thinking about sending you one of the two to test as it isn’t being used RIGHT NOW. Any thoughts on turnaround time? I would think it would be a very quick test suite but I may be wrong. I’m really eager to see what you and the AP can tease out of it.

I’m not sure if it would affect the general applicability of the tests, but the PC-2XR reduces a balanced pro line level to a consumer RCA line level - and is a godsend if you want to drive high gain single ended amps with something with balanced outputs. I level matched and did a Hillbilly Randomized listening test of the balanced output of a DAC3 HGC through the PC-2XR against the HGC’s RCA outs and could not hear one bit of difference. But I was listening at moderately high Chicago High Rise listening levels with the normal Chicago High Rise background noise levels so I will not claim the best bass (etc.) distortion detection acuity.
 
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Indeed. I keep thinking about sending you one of the two to test as it isn’t being used RIGHT NOW. Any thoughts on turnaround time? I would think it would be a very quick test suite but I may be wrong. I’m really eager to see what you and the AP can tease out of it.
It is a quick test but I still have to test what comes before it. My usual lead time from arrival of gear is about 4 weeks.
 

JEarle

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Can’t you just use a dongle for this sort of thing? Even the Apple dongle has 96 SINAD
Doesn’t have XLR outs, probably don’t want to accidentally put phantom power up it’s output. A dongle is also much easier to lose / break / steal.
 

AudioTodd

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It is a quick test but I still have to test what comes before it. My usual lead time from arrival of gear is about 4 weeks.
I don’t see my ever changing audio experimentation needing it within that time, so I will see if I can pack it up nicely and send it in. The builder of one of my monoblock sets (Wilson Shen “of“ [it‘s just him] Clayton Audio - BJT Class A amps) recommends Jensen transformers for people who want to use single ended devices to drive his current large and balanced-only amps, so I’ve always wondered how good they really are despite my own successful use of them.
 

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To be fair, Peavey is not the first name that comes to mind for home hi-fi.

But to their credit, my late friend and former high school sock hop bandmate went on to become a moderately successful regional rock and roll hero whose band scored multiple Peavey endorsements along with lots of cool gear.
 
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F1308

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Now, when it is stated than THE CHEAPER, THE BETTER, it doesn't mean at all you are to plummet across the 100$ barrier, but of course.
 

Vasr

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I am not sure this should even be reviewed here.

For those not familiar with Peavey, they are a low-mid end music instrument, amps and stage pro-audio equipment much below Marshall and Fender and I don't think they have ever built a low distortion product. :)

A lot of tweener budding guitarists start with a Peavey amp especially if into metal thrashing. They are cheap, loud and provide the needed distortion.

This was probably put in the lineup for mixing in audio from a laptop into stage DJ equipment.
 

GimeDsp

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Man, there must be a ton of equipment with pin 1 issues out there to make manufacturing such a device worth it. At 50 bucks for something robust and simple, I don't think you can beat this at its intended use.

The output level sure is pretty pathetic though.
Well, the more power a transformer has to handle cleanly the more expensive it gets. Just a guess, but (Peavey) operating the transformer at a lower level and allowing the gain on whatever it is going into to make up the differece to "line level" or nominal level for that device makes some sense.

I think this is the perfect place to test any pro audio gear, Its not likely anyone in the pro-audio centered places will have the gear or desire to test it. ALSO evey once in a while Amir will test a low $$$ peace of gear that turns out to be amazing for the price. Without testing low end stuff you would never know whats a hit or miss.
 

Francis Vaughan

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If there is chance to measure some other parameters, IMD would be interesting, as well as level dependence. Mostly one is just measuring the transformer. But transformers are evil things, and the distortion is heavily dependent on the absolute magnitude of the magentisation in the core. So the distortion profile is very different to those we are used to with other electronics. Intermodulation is potentially a big problem. The lower the frequency, the worse things get for everything.
 

restorer-john

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I am not sure this should even be reviewed here.

For those not familiar with Peavey, they are a low-mid end music instrument, amps and stage pro-audio equipment much below Marshall and Fender

With respect, if we applied that same brush to everything, there would be no SMSL, Topping, Ciunas, March Audio, LoxJie, Dutch & Dutch, Kii or Mola-Mola reviewed here on ASR at all. What are you suggesting the pre-requisites are?

Peavey has been around for 63 years, since 1957, 5 years before Marshall and their gear even existed. If anything, they deserve to be reviewed more than a boutique, flavor of the month, or flash in the pan company wouldn't you say?
 
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