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My Unhappy Project Phono Box DS Experience

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My Unhappy Project Phono Box DS Experience

Postby Garven » 29 Apr 2013 02:34

Yesterday I picked up a new Project Phono Box DS and was looking forward to not only the possibility of slightly better sound than my trusty old Cambridge Audio 640P (no complaints about its sound really) but especially the adjustments since the 640P is rather inflexible with its 220pF-only capacitance for MM and 100ohm-only impedance for MC.

So I got the DS home, hooked it up and started spinning vinyl with my Project Xpression II equipped with an Ortofon 2M Black. It soon became apparent that something was wrong. It sounded like there was a peak in the upper midrange and greatly diminished highs above that.

I did some measuring with pink noise from three test records, frequency sweeps, and music. All revealed the same frequency curve: a 6db peak around 5k with a -12db roll-off in the highs bottoming out around 15kHz!

Phono Box DS curve 2013-04-27.jpg
Phono Box DS curve 2013-04-27.jpg (30.43 KiB) Viewed 14003 times
Worse, the capacitance settings had absolutely no effect on the curve. Switching through the 47pF 147pF, 267pF and 367pF capacitance settings did absolutely nothing to shift the peak or the trough. I've played around with capacitance plus (like loading plugs) a bit and observed how capacitance changes the position of resonant peaks, so this was definitely not a case of high capacitance causing the peak to lower to 5k. Besides, that would take 1600pF of capacitance! My turntable wiring plus Blue Jeans interconnects definitely don't add up to 1500pF!

I own three phono stages, the 640P, plus a Yaqin MS12B and an Art DJ Pre II. None of them show this much of a variation in frequency curve. The Yaqin's slightly warmer and the Art sounds a bit compressed, but all three show a similar frequency curve from the 2M Black with a slight peak of 2dB around 18k, just as in the initial reviews of the cartridge.

Needless to say, I'm returning the Phono Box DS tomorrow! Too bad. I viewed it as a nice flexible phono stage that would not only work well with MM carts but also when I eventually move to MC.

Anyone else run into something like this?
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Re: My Unhappy Project Phono Box DS Experience

Postby smeg68 » 29 Apr 2013 06:35

I would deem that faulty. If they are all like that then someone made a BIG mistake at the design stage...!
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Re: My Unhappy Project Phono Box DS Experience

Postby E.Man » 29 Apr 2013 08:41

Yow !

Other owners comments would be good.
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Re: My Unhappy Project Phono Box DS Experience

Postby T.O.S. » 29 Apr 2013 10:26

Can't you try another unit ? Maybe that was faulty ...
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Re: My Unhappy Project Phono Box DS Experience

Postby davidsrsb » 29 Apr 2013 15:18

Its difficult to see how a RIAA error could do this, getting the 75us too high would cause the rise starting at around 1kHz, stop rising at the higher frequency, but then stay at a constant level. This looks more like there really is a nF range capacitor on the input.
The values you quote imply the input is loaded by a fixed 47pF with 100pF and 220pF independently switched. My best guess is that the unit was built with something in place of the 47pF. Unfortunately other units in the same batch, using the same reel, will also be wrong
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Re: My Unhappy Project Phono Box DS Experience

Postby Garven » 29 Apr 2013 18:15

I think it probably was a bad unit. I returned it during my lunch break. They didn't have another one in stock, so I went for a Tube Box S. We'll see how this sounds.
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Re: My Unhappy Project Phono Box DS Experience

Postby Garven » 29 Apr 2013 23:46

I need a crane to pick my jaw up off the floor. As bad as the obviously defective Phono Box DS unit sounded, the Tube Box S sounds tremendous. New records, old records, they all sound layered with more detail and depth than I thought my rig had in it. This little box smokes my old 640P! Definitely worth the money. I'm really glad I decided to take a chance on another Project.
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Re: My Unhappy Project Phono Box DS Experience

Postby E.Man » 30 Apr 2013 00:45

Well good outcome but the DS- is the one in my budget and this smacks of QC.

Where are they getting them built ?
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Re: My Unhappy Project Phono Box DS Experience

Postby E.Man » 30 Apr 2013 01:58

E.Man wrote:Well good outcome but the DS- is the one in my budget and this smacks of QC.

Where are they getting them built ?


Or... seeing as you didn't get to try another unit they're all like that.

Was it the DS+ with the display or the DS- with just the buttons on the front ?
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Re: My Unhappy Project Phono Box DS Experience

Postby davidsrsb » 30 Apr 2013 10:31

The response in the graph would sound very odd. Very sibilant vocals and no cymbals
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Re: My Unhappy Project Phono Box DS Experience

Postby Garven » 30 Apr 2013 12:40

E.Man wrote:
E.Man wrote:Well good outcome but the DS- is the one in my budget and this smacks of QC.

Where are they getting them built ?


Or... seeing as you didn't get to try another unit they're all like that.

Was it the DS+ with the display or the DS- with just the buttons on the front ?
DS- with just the buttons. It may well have been a defective unit. The dealer also said he played around with the Tube Box DS when it came in and had problems getting the controls working properly until he called Project and discovered that the documentation stated to do the opposite of what needs to be done to get everything working properly. There was a jumper on the back that the document said needed to be removed to use the front controls and in fact, you need to make sure it's installed to use the dial on the front!

In my case, there were no jumpers on the DS-. The Tube Box S has jumpers and they work well. I was able to clearly see the resonance peak move downwards as I increased capacitance last night during tests with pink noise from the hifi test lp. Although they recommend the 150pf setting for the Ortofon 2M Red in the web version of their manual (strangely, the simple sheet that came with the unit was missing the "typical" recommendations in the web version). I found that my 2M Black balanced nicely with the 50pF setting with just the +2dB hike up around 18k that I saw mentioned in reviews of the cartridge.

I listened to the phono box s quite a bit last night and I'm really thrilled with its sound. I'm noticing many fine details in the high end that never seemed to be there before, plus the bass is solid and full. The air around the instruments and sense of space is interesting. With my old CA 640P, I was getting a good sense of ambiance and depth, but it sometimes seemed a bit disembodied or something hard to describe. With the new one, it's just as strong if not moreso, but the whole thing seems unified, or rather the instruments seem better placed throughout the ambient field.
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Re: My Unhappy Project Phono Box DS Experience

Postby E.Man » 30 Apr 2013 14:11

I'm running Ortofon MC10 Supreme into Musical Fidelity V-LPS with V-PSU. Thoughts of getting something with variable settings on a tight budget without going downward in quality lead me to consider the Project Phono Box DS-.
There are no shops near me so I can't audition.
Since the budget at the moment is so tight I was just thinking of forgetting about it for a while. Maybe by the time I get back to it they won't be selling faulty ones. I don't have the diagnostic tools that you do.
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Re: My Unhappy Project Phono Box DS Experience

Postby T.O.S. » 30 Apr 2013 17:42

Thank you ,Garven,for this subject , in fact I was looking for a upgrade for my 640P ,and didn't get very encouraging feedback , not many users of project phonostages .
I am curious if you are interested to test a good DS model instead that faulty one , against the tube box S and the 640P . It would help me to choose .I don't have shops in my area and can't audition them before buying .
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Re: My Unhappy Project Phono Box DS Experience

Postby davidsrsb » 01 May 2013 09:23

The bad batch is probably a few hundred units as it is probably one wrong reel on the pick and place machine
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Re: My Unhappy Project Phono Box DS Experience

Postby Pikey » 01 May 2013 13:21

How did you generate the oscilloscope graph Garven?

I would be interested in having a stab at that myself!
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