Pro-ject Phono Box MM Review

[Angsty]

Thanks @amirm for this informative and critical review. It seems to perform well enough for what you pay.

There are better options near this price point.

This pro-ject thing is a basic MM stage in a cheap can. Hardly worth the time of day, letlone a review.

The review is simply a consumer warning.

 

[Sernyl]

The capacitor is not in series, of course.

View attachment 298792


There is a old video where the problem is explained. Other users also have reported about this later. I am not sure if they have fixed it with the LP5X.
I also had the problem with a Hanpin DJ-Turntable and had detected it by my own already. It made a big difference in high frequency response.

There is also the cable capacitance...

 

[restorer-john]

Yes, please! Pictures, or it did not happen.

Here you go. My old girl has been sitting in a box since the late 1980s. She got an identical arm (the counterweight decoupling rubber had perished resulting in the counterweight sagging badly) pulled from a parts donor APQ-50. Had her deteriorating phono leads and power lead replaced, a replacement antiskate spring from the donor and a full alignment and setup to spec. I also cleaned out and re greased (with special ultra high viscosity 500,000wt silicone oil) the damped cue cylinder to have the arm raise and lower perfectly.

Love that funky 1980s "quartz lock" printing.... Single point strobe, neon lit from PLL QL IC. The single point strobe is also monitored by an IR LED/TR interrupter to give feedback to the main IC.

Optical sensed lift of via LED/LDR and solenoid operated auto return shut off. No physical arm contact.

Arm lower base is alloy

Headshell is magnesium alloy with the original PC-90 (AT) dual magnet cart. Stylus was replaced in the 1980s. Zero wear under high powered magnification.

Fun fact:
The APQ55 has an inbuilt overhang set point built into the rubber platter mat. Of the three concentric inner rings, you centre the stylus above the middle one when the cart is moved over the spindle. Brilliant!

Other fun fact2:
Many other Japanese 1970s and 1980s TTs have overhang gauges moulded into the backside of their original platter mats- turn them over to see.

Fun fact 3:
Some brands also built in overhang set points on strobe lights upper bodies.

 

[restorer-john]

What phono stage overloads at 220mv?

The MM phono stage in a Sony TA-3650 integrated from 1977.

It came in at number six in terms of overload when I tested 13 or so phono stages I had lying around. The best was 320mV...

 

[computer-audiophile]

Here you go. My old girl has been sitting in a box since the late 1980s. She got an identical arm (the counterweight decoupling rubber had perished resulting in the counterweight sagging badly) pulled from a parts donor APQ-50. Had her deteriorating phono leads and power lead replaced, a replacement antiskate spring from the donor and a full alignment and setup to spec. I also cleaned out and re greased (with special ultra high viscosity 500,000wt silicone oil) the damped cue cylinder to have the arm raise and lower perfectly.

View attachment 299147

Love that funky 1980s "quartz lock" printing.... Single point strobe, neon lit from PLL QL IC. The single point strobe is also monitored by an IR LED/TR interrupter to give feedback to the main IC.
View attachment 299148

Optical sensed lift of via LED/LDR and solenoid operated auto return shut off. No physical arm contact.
View attachment 299149
Arm lower base is alloy
View attachment 299150

Headshell is magnesium alloy with the original PC-90 (AT) dual magnet cart. Stylus was replaced in the 1980s. Zero wear under high powered magnification.
View attachment 299151

Fun fact:
The APQ55 has an inbuilt overhang set point built into the rubber platter mat. Of the three concentric inner rings, you centre the stylus above the middle one when the cart is moved over the spindle. Brilliant!

Other fun fact2:
Many other Japanese 1970s and 1980s TTs have overhang gauges moulded into the backside of their original platter mats- turn them over to see.

Fun fact 3:
Some brands also built in overhang set points on strobe lights upper bodies.

Thank you, very nice - and with a slightly better pickup you could definitely get a better sound out of it.

 

[restorer-john]

Thank you, very nice - and with a slightly better pickup you could definitely get a better sound out of it.

I have a heap of cartridges here. I just leave that TT original as it reminds me of my youth.

 

[computer-audiophile]

I have a heap of cartridges here. I just leave that TT original as it reminds me of my youth.

I see. You could check the tracking ability with a test record and see how high you still get with this pickup. Also your pickup was certainly more flexible in his youth.

 

[SIY]

What phono stage overloads at 220mv?

At what frequency?

 

[SIY]

Just to confirm : when I got my Audio-technica LP5X, I was sceptical but curious about the "line" output.
My very old phono pre-RIAA kit was ways better :
View attachment 298762


View attachment 298763

BTW, needless (no pun intended) to say that the elliptical stylus of the VM95E was replaced by a ML : huge difference.

The schematic suggests that this is a very non-optimal design for MM.

As I have pointed out in the past, S/N past (say) 80dB (I'm excluding discrete frequency, like hum) brings no benefit since the cartridge's Johnson noise will then dominate. With a stage like this and an MM, the noise would be much worse than any measurement Amir would present since his test method is almost completely insensitive to current noise.

 

[cgallery]

At what frequency?

Well I don't know guess that would be important too.

But allowing for 35db of headroom on the vinyl seems extreme. But maybe I'm looking at it incorrectly.

 

[SIY]

Well I don't know guess that would be important too.

There's more than a 40dB swing in gain over the audible range, so it's a vital bit to specify. Of course, advertising specs tend to be quite vague...

 

[restorer-john]

I see. You could check the tracking ability with a test record and see how high you still get with this pickup. Also your pickup was certainly more flexible in his youth.

The 40 year old stylus will easily track the bass drum tests at +4db, +8dB, +12dB perfectly and +16dB with some distortion at 1.5grams VTF. There appears to be no more or less deflection as can be the case when the elastomers dry out/or go soft and collapse. Most ATs seem to last many more decades than some of the other, more esoteric brands. I use several test records, and for tracking the old W&G 24,2434 is a great way of sorting the wheat from the chaff. I have a few copies of that test record.

 

[restorer-john]

Well I don't know guess that would be important too.

But allowing for 35db of headroom on the vinyl seems extreme. But maybe I'm looking at it incorrectly.

Phono overloads were pretty much always specified and tested at 1kHz.

That's what I do. I drive my phono stages with a 1kHz sine (600R source), vary level until the output clips, then wind it back a touch, check the THD and read the input applied voltage (in mV). I can also sweep also using an attenuated inverse RIAA filter to see if there's any reason to revisit the 1kHz number.

The Sony amp I mentioned above was one I had sitting on a pile of unused subwoofers within easy reach, so it got used with the TT. Its rated MM overload was 210mV. I measured ~220mV (217mV) on a rainy day several months back when I was amusing myself with phono stages on gear that was laying around...

The units with the highest overloads necessarily run much higher rails than is typical to accommodate the swings/gains needed. The Denon can swing almost 20V RMS out the tape outs. I've got a Kenwood LO7C here which has +/-47V rails for the MM and MC stages and its overload capability is over 350mV (1kHz/0.003%).

 

[computer-audiophile]

Der 40 Jahre alte Stift wird die Bassdrum-Tests bei +4 dB, +8 dB, +12 dB problemlos und bei +16 dB mit etwas Verzerrung bei 1,5 Gramm VTF problemlos verfolgen. Es scheint keine mehr oder weniger Durchbiegung zu geben, wie es der Fall sein kann, wenn die Elastomere austrocknen/oder weich werden und zusammenbrechen. Die meisten ATs scheinen viel länger zu halten als einige der anderen, eher esoterischen Marken. Ich verwende mehrere Testaufzeichnungen und für die Nachverfolgung ist das alte W&G 24,2434 eine großartige Möglichkeit, die Spreu vom Weizen zu trennen. Ich habe ein paar Exemplare dieses Testprotokolls.

You know very well, better than many others, I am aware of that! I would like to say that in advance.

I have had old AT cartridges of this type, where the needle suspension had become harder after decades, not softer. I therefore prefer to use new pickups.

To explain: I always do a trackability test first with new or unknown cartridges. It gives information about the trackability of my tonearm/cartridge combination. The higher the achieved value (micron), the better the respective tonearm / cartridge combination is able to sample difficult groove modulations without distortion. I aim for a value above 80 µ.

 

[LtMandella]

OT, I know, but would you mind to reveal which ultrasonic cleaner you use?

it was just a generic china manufactured ultrasonic tank. I got mine from Amazon. The vendors bundle the ultrasonic cleaner with a simple device that has mounts on the side of the tank with a motor mount to rotate the LPs in the bath. The vendor name would not mean anything really since it was just a relable of a generic tank cleaner.

 

[LtMandella]

Tidal e.g. makes a business model out of surpassing the CD quality. Their term MQA is meant to allude to the fact that the songs have a similar quality as if they had been played back from the master in a recording studio.

MQA encoding is lossy. The marketing hype from that company about MQA sound quality I believe has been discredited.

 

[Mr Vinyl]

The sound is bad on this thing. The highs are splashy (like a smear) and grainy. For example, cymbal hits don't sound smooth at all.