MSB PAD-1 (90's era ADC) - Now with measurements

[DWPress]

I recently ask Amir if he would be interested in measuring this interesting piece of kit that's been in my system rotation for many years but, given it's vintage, he understandably declined. I've always wondered how the ADC measured though especially with the specs MSB gave it. It is limited to 24/96kHz operation because of the dated Crystal CS5396 chip which was very well regarded at the time and continues to see use today. The features are the main compelling use though and I wish someone would make an updated version of it with modern components and chips.

Inputs: balanced XLR unbalanced RCA MM phono preamp

Outputs: AES/EBU optical toslink coax RCA

Resolution___________________________________________________________________ SNR Line Level Input Phono Input XLR input Dynamic Range______________________________________________________________ Total Harmonic Distortion THD + N Channel Separation __________________________________________________________ Interchannel Phase Deviation Sampling Rate_______________________________________________________________ Passband ripple Stopband ripple______________________________________________________________ Digital Outputs Analog Inputs________________________________________________________________ Weight Dimensions

24 bit 120 dB 100 dB 144 dB 0.0006% 105dB 120 dB 0.0001 degrees 44.1, 48, 88.2, 96 kHz +/- .005 dB >117 dB Coaxial, Optical and Balanced Phono MM, 2.5 mV/ 47 kOhm; Line Level, 2V P-P full scale; XLR, 13V RMS 18 lb. 17” x 14” x 1.75” Rack mountable

Edit: I got curious enough about the specs that I dug out my Windows box and got a crash course in @pkane's Multitone app and REW with some gracious assistance from @Blumlein 88. Results on this 30 year old gear are not quite manufacturer's spec but still decent at around -84 db or .006% dynamic range - which isn't bad, good low noise level, good linearity and quite respectable distortion from the device. To quote @Blumlein "...back then ADC's were already a solved problem." All this before USB was even a standard and many hard drives were still measured in megabytes.

All tests done in 24/48kHz unless noted because that's convenient for working with a Umik and what I generally run my system at. I ran tests at 44,88 and 96kHz too but the results were negligible in comparison. Tests were conducted with my Okto DAC8 Pro which allows me to send and received 8CH USB audio signals. Test signals sent to the Okto connects via XLR out 1&2 to MSB balanced input L&R. MSB AES output feeds it back to the Okto and USB back to the computer. The Okto has exceptional measurements on its own so graphs should be pretty accurate.

distortion	frequency response	linearity	Multitone32
multitone500	Sweep IMD DIN vs Level -1db	Sweep THD v Level 48kHz 0db	Sweep THD v Level 96kHz -1dB

Noisefloor

Sweep THD vs Level

Jitter

I use this thing primarily to route my phono preamp into my Okto dac8 Pro via the AES connection which sends the converted signal to my computer via USB. It is then routed through my active crossover and room EQ and sent back to the Okto on USB for 8 channels for woofers, mids, tweeters and 2 subs. I'm sure the MSB is more than adequate to act as an ADC for vinyl playback even if it is approaching 30 years old. Even better it's the same size as the Okto and stacks nicely with it with minimal blue and orange LEDs.

I still see these in resale, currently one on eBay for $200, so I think it is an interesting option for anyone in a unique use case scenario like me. Given MSB's reputation and $$$$$$$ prices these days the PAD-1 originally retailed <1K in the era before MSB became what they are now. They made another version, the ADD-1 that has 8 pair of RCA inputs with auto switching and the same outputs. I have one I no longer need if anyone is interested or I'll put it in a listing here on ASR if this thread gets any traction.

 

[DWPress]

Here are the specs for the ADD-1 for comparison and pics:

 

[Blumlein 88]

I had one of the ADD 1 devices. When MSB made excellent gear at excellent prices instead of stupidly expensive gear. I had an expensive DAC, and a Meridian 518 (which was something of a good quality digital preamp). I decided to get an ADC and digitize all my analog sources. FM, cassette, phono, and RTR. It worked out great. I convinced a couple friends to get them. One of the important early experiences about audio. I convinced myself and a few others that there was nothing wrong with digital. I used this ADC, a good DAC and let people hear the ADC-DAC vs straight thru with various sources (level matched). Without telling them which was which they couldn't tell a difference. I moved toward digital away from analog from that point on.

I don't know what other affordable ADCs were available then. Maybe some pro units were, but I did not know about it. So these units at these prices were really something. But they had a limited market I guess. Many audiophiles viewed digital as bad. You didn't have a way then for recording things you sent thru it digitally. So only a few people doing what I was had any need for it. I purchased the one I had for like half price about 2 years after it was introduced. They apparently could hardly give them away. I sold mine at some point, but really could have used it several times. Even now a handy device to have. No computer needed to control it. Just feed it analog and get a digital signal out of it.

I don't even know if there is a comparable stand alone device like it now.

 

[DWPress]

I don't even know if there is a comparable stand alone device like it now.

Exactly! Born 30 years too soon! Which is why I'd love to see the actual measured specs of these things.

 

[Blumlein 88]

Exactly! Born 30 years too soon! Which is why I'd love to see the actual measured specs of these things.

It would be nice to know. While proof of nothing, the Link DACs they made in those years generally met specs when tested by Stereophile.

 

[epicure]

I still see these in resale, currently one on eBay for $200, so I think it is an interesting option for anyone in a unique use case scenario like me. Given MSB's reputation and $$$$$$$ prices these days the PAD-1 originally retailed <1K in the era before MSB became what they are now. They made another version, the ADD-1 that has 8 pair of RCA inputs with auto switching and the same outputs. I have one I no longer need if anyone is interested or I'll put it in a listing here on ASR if this thread gets any traction.

Do you have a PAD-1 or an ADD-1 for sale?

 

[DWPress]

Do you have a PAD-1 or an ADD-1 for sale?

I'd be happy to make the ADD-1 available. PM me and I can send you a PDF of the manual.

 

[epicure]

Thank you for clarifying. I am looking for the functionality of the PAD-1. Unfortunately, the seller on ebay does not want to ship to South Africa...

 

[DWPress]

Unfortunately, I don't want to ship to South Africa either - sorry.

 

[formdissolve]

The RME ADI-2 Pro FS does all that and more.. for a price! Still, you can find them for $1300 used or less sometimes. Edit: I suppose it doesn't have a MM input - you'd have to get the super expensive version for that.

Still a cool piece of gear. The only 90s components I have left are a Parasound D/AC-1000 DAC that I still use in my main system and a Denon DRA-635 that I was using for years in my back office (the thing never seems to want to die).

 

[Timcognito]

This may be of some interest. A good friend has a few versions of these Alesis ADAT. BTW I still have my MSB Link DAC III with upgrades and sounds as good as my Topping E30 to my ears.

 

[formdissolve]

This may be of some interest. A good friend has a few versions of these Alesis ADAT. BTW I still have my MSB Link DAC III with upgrades and sounds as good as my Topping E30 to my ears.

I had a similar Alesis and used it for awhile. Cool pieces of gear

 

[Blumlein 88]

Nice measurements for an old piece of gear. Still working and useful today. Doesn't need any computer connection to work.

 

[kemmler3D]

This is a great post because it shows how long we've had transparent-enough digital devices. And still we have people fretting over whether digital sounds good enough, or whether a DAC that performs 100x better than this is adequate.

This post conveys much the same lesson that ASR in general conveys - calm down and save your money for better speakers.

 

[DWPress]

Amen!

Although 30 years is about the maturity of the internet as well and there's been all that time in between for every sort of non-issue opinion to manifest into the crap fest we have now.

 

[DWPress]

Compare this thing against some of the ADCs Amir has measured here.

 

[AnalogSteph]

If it didn't have relatively high HD2 going on, it could pass for a modern lower-midrange audio interface. I guess the opamp complement in the unbalanced part of its input stage may be worth looking at... the flatness across the audible range possibly suggests common-mode distortion. Choices among high-performance parts 25 years ago weren't what they are today.

 

[DWPress]

Choices among high-performance parts 25 years ago weren't what they are today.

And today there's nothing else in home hifi quite like it. As I said, I'd love to see a modern version with the same features.

 

[AnalogSteph]

I mean, if push comes to shove there's still the option of modifying the PAD-1. Asking MSB for any documentation they might have is worth a shot, otherwise some reverse-engineering is going to be required.

I'm slightly worried that the distortion bottleneck may turn out to be the input switching (worst-case there's a 4053 or 4066 in there), but even then there's some avenues worth exploring.

 

[DWPress]

I'm pretty sure that's outside my level of expertise but I am handy with a solder iron. You are proposing that a opamp upgrade could potentially improve distortion measurements? With a little more information and testing of course.

I'd be happier if Topping or someone else would take on making a device like this today. At any rate the "bottleneck" is still lower than what my phono preamp is feeding into it.