Modwright upgraded Musical Paradise MP-D2 v.2

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JakeJ

Modwright upgraded Musical Paradise MP-D2 v.2
« on: 10 Jul 2018, 12:11 pm »
Modwright upgraded Musical Paradise MP-D2 v.2

I bought a used Musical Paradise from a fellow AC member about six months ago and really enjoyed it over my Metrum Acoustics HEX.  The HEX is quite neutral but can sound a bit thin on certain material.  I decided to try a DAC with a tube analog section and the D2 came up for sale on AC for a reasonable price.

The first thing I noticed about the D2 was the bass.  Much, much fuller and slightly bloated.  Mids were richer and the soundstage increased in width and depth.  Treble was nice and smooth but a bit reticent, as if it were damped down.

I liked it better than the HEX overall so the HEX was retired.  I listened to the D2 for many hours with great pleasure when Dan Wright opened a thread in his circle about having the itch to find some new gear to apply his upgrade magic to.  Knowing the Modwright reputation I got curious as to what Dan could do.  After establishing contact Dan gave me his plan which was simply to evaluate the unit and find any weaknesses.  Then plan out the upgrade.  Dan found the overall design to be quite good and felt that the circuit was not optimized for the 6922 tube (specifically bias) and that the power supply could use some better regulation downstream from the rectifier tube.  We discussed his plan and I said go for it!

When I got the unit back I had a little glitch in my audio chain, the tubes in my preamp wore out to the point the one triode in one of the four 12AU7’s in the circuit read “23” when the minimum is “46” (TV-7D/U tester).  So after some trial and error (read bad tubes in my stash) I got it up and running again.

Finally a chance to listen to my newly tweaked MP-D2!  First up is Jesse Cook “Beyond Borders” ASIN B073XVMW17 both the title cut and Double Dutch followed by AfroCelt Sound System Vol. 2 “Release” ASIN B001DPC3VA Big Cat and Vol. 3 “Further In Time” Colossus.  These tunes have a lot of complex passages, tons of bass, and combine acoustic and electronic instruments to paint their sonic canvas.  The bass bloat is now gone but bass is still full and deep.  I think the bloat was masking some of the bass definition as well.

Mids and treble is fuller and more open, a bit more forward but that includes an increase in front to back depth of the soudstage.  It was about 4-6 feet before, and mostly forward of the front baffles.  Now it is about 6-8 feet deep and reaches behind the front baffles much further.

Next up was John Coltrane "Blue Train" ASIN B001KP0AKY RVG Edition the title cut Blue Train was reverb city as expected.  Rudy had great ears! JC was followed by Joni Mitchell's Blue from the album of the same name, ASIN B000002KBU, for a taste of female vocals and Joni's smoky voice was conveyed perfectly.  I finished up with KT Tunstall's Blackhorse and the Cherry Tree from " Eye To The Telescope" for some gritty rockin' tunes.

To sum up the Modwright mods, the primary benefit is better top to bottom balance, along with a deeper soundstage, and clearer mid through treble range.  Big improvements all around and I heartily recommend it!

Good job, Dan!

BTW, besides the Modwright mods which consisted of a voltage regulation board and proper biasing resistors I installed four Mundorf S/G/O caps in the output coupling positions and four matched and balanced JJ E88CC gold pin tubes.

modwright

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Re: Modwright upgraded Musical Paradise MP-D2 v.2
« Reply #1 on: 10 Jul 2018, 04:30 pm »
Thanks Jake for posting this review!

The Musical Paradise D2 DAC is a good product! I feel that it has a few shortcomings that we address and that make it truly great!

The mod includes:

Re-bias of the tube stage allowing for lowest distortion and optimum operating point for the tube. We use premium audio-grade resistors in the signal path.

Adjust the operating high voltage supply to the tubes to provide the required optimum voltage for the ideal bias point.

Install MWI bypass capacitors at the B+ supply to the tubes where the stock supply has no bypass caps at all.

Lastly, we install our own proprietary SSHVR - Solid State High Voltage regulator to provide a rigid and solid supply for the critical plate voltage. Without regulation, as the stock design is implemented, any fluctuations in the AC mains supply means some fluctuation in the plate voltage. The best power supply is tightly regulated to allow for robust bass, lower distortion and faster transients. With the SSHVR install, now matter how the AC mains fluctuates and no matter what current demands are required at the tube, the plate voltage remains rock steady.

The end result is better bass, resolution, soundstage, dynamics and speed.

The tube rectifier is still retained and I believe this is important as I like the sound of tube rectification, even WITH Tube Regulation.

To clarify, the tube rectifier converts the AC voltage to DC.  The Regulator takes the incoming DC voltage and regulates it to a lower voltage, that is very clean DC and without fluctuation. As the incoming higher voltage to the regulator fluctuates, the regulator maintains the lower voltage at a fixed output. It acts in a way, like a spring, absorbing the incoming voltage fluctuations.

The cost of the modification is $500. This is a fixed price and will not be discounted. Our standard player mods are $2500 for the Oppo, Sony and Marantz players.  This mod requires less work of course. You are paying for our knowledge and engineering as well as for the audio grade parts.

Many modification companies exist, and they are largely charging you for the cost of expensive audio grade parts that they simply replace for stock value parts of lower value. I consider this an upgrade but not a modification. A modification involves actually changing and improving the circuit design. A true mod, in my opinion, involves judicious engineering changes that SIGNIFICANTLY improve the product. We also use audio grade parts, where they make the biggest difference. You as customer can easily add damping to the chassis, upgraded footers and other such upgrades. We offer the our knowledge of audio engineering.

I look forward to hearing from you, as I know that there are a lot of Musical Paradise D2 DACs out there and for GOOD REASON!  My hat is off to Musical Paradise for their design and what they are able to produce at a VERY low price! The D2 DAC represents an EXCEPTIONAL value in a high end tube DAC!

Sincerely,

Dan W.
360.247.6688
modwright@yahoo.com