Inside High End Equipment

[STC]

Line5

 

[Barton]

Here is some Teddy Pardo equipment. Pity it appears to be discontinued as it sound very good and continues to respond well to ever cleaner source components.

 

The PR1 preamplifier and power supply:

 

 

 

 

 

 

[Barton]

The Teddy Pardo MB100 monoblock amplifier. Interestingly, it appears to be two parallel amplifiers. 

[STC]

Meridian 101 & 105 . It is about 40 yrs old. I thought audiophiles don’t like EQ. 
 

 

[Barton]

The Mojo Audio Mystique 3 DAC. This thing is quite the brick with its massive power supply circuitry. Sound is sublime. This DAC can still keep me in my seat for hours.

[STC]

Mark Levinson No. 52 Reference Preamp.

 

 

[STC]

Audiophile scientist modify Marantz CD67. Bare copper rods that can kill you. 
 

 

[Solstice380]

4 minutes ago, STC said:

Mark Levinson No. 52 Reference Preamp.

 

That’s what can be done when the mfr. can spend money on good engineering and manufacturing.  And the selling price will reflect that.  Not good that something failed in that high end of a component, though!

[Solstice380]

3 minutes ago, STC said:

Audiophile scientist modify Marantz CD67. Bare copper rods that can kill you. 

 

OK so I get the heavy gauge wire, but no insulation?  Darwin Award!

[STC]

6 minutes ago, Solstice380 said:

 

OK so I get the heavy gauge wire, but no insulation?  Darwin Award!

 

I have seen more mind blowing modifications than this. 
 

Regarding the ML, good parts but wonder why make things more complicate. There was one pre or amp that had a part which can be bypassed and made no difference at all. Not sure if I posted that here. 

[ShawnC]

2 hours ago, STC said:

Audiophile scientist modify Marantz CD67. Bare copper rods that can kill you. 
 

 

So that's how they got that killer sound 😉, love the pictures.

[mourip]

3 hours ago, Solstice380 said:

 

OK so I get the heavy gauge wire, but no insulation?  Darwin Award!

 

I guess that it is OK when you also have no mains ground wire? 😬

 

(Needless to say but I will anyway. Just kidding!)

 

[Barton]

Probably not any sonic benefit to the bare wire but it's really not a safety concern nor code violation. There are always exposed terminals and often bussing as well inside enclosures. An open energized tube amp can really hurt you! Anyone comfortable enough to take a cover off should know to unplug and verify voltage before touching anything. With many electronic devices the biggest hazard is you'll fry it without anti static discharge care.

[mansr]

3 minutes ago, Barton said:

Probably not any sonic benefit to the bare wire but it's really not a safety concern nor code violation. There are always exposed terminals and often bussing as well inside enclosures. An open energized tube amp can really hurt you! Anyone comfortable enough to take a cover off should know to unplug and verify voltage before touching anything. 

Even if it can't be avoided entirely, exposed metal carrying lethal voltages should be kept to a minimum. The thing pictured is inexcusable.

[Ralf11]

The safety of the consumer needs to be accounted for but also the safety of a service tech who will need to run it w/o the case one.

 

Yes, inexcusable.

[sandyk]

10 hours ago, STC said:

Audiophile scientist modify Marantz CD67. Bare copper rods that can kill you. 

 

  A huge number of CD65 , 67 etc. were modified by various specialist firms and DIYers, however none as dangerously as this one .

 I had a heavily modified CD65 which was capable of extremely good results until the various IDP plugs and sockets became too unreliable and annoying to keep repairing.

[One and a half]

Nothing wrong with bare wires internal to equipment. In normal use, access to the inside is by the way of a key or tool, totally legal.

 

Problem is, the right hand connection has split the plastic, under the right circumstances can track to the outside from the bare terminal. There is quite a bit of kit removed on the mains board, or bypassed, you can see the original connections at the hot and cold points on the board.

The bare copper wires can be come loose at the board since the split can get wider. In the case of semiconductors soldered directly on boards, there's heat expansion through years of power cycling that causes the solder to come adrift from the pads and the music stops.

 

[Barton]

While we're on the subject of modified gear this is my latest effort. Sparkos labs has a new and much better discrete class A op amp than what was used in the Mojo Audio Mystique 3 pictured further up this page. It is physically 4 times larger and the pins are different necessitating the elevated board. The sound quality of this DAC was already excellent, and this upgrade to the analog side improved sq dramatically. The difference is as big as any single system upgrade I've done yet. Mojo Audio has a new DAC coming out soon which is rumored to also use these new op amps. Will be worth a listen for sure.  

[sandyk]

2 hours ago, Barton said:

Sparkos labs has a new and much better discrete class A op amp than what was used in the Mojo Audio Mystique 3 pictured further up this page

 

 Have they published Distortion, Supply Rejection (PSRR) ,Bandwidth measurements etc. for these discrete opamps ?

[Barton]

https://sparkoslabs.com/wp-content/uploads/2018/03/SS2590.pdf

[sandyk]

24 minutes ago, Barton said:

https://sparkoslabs.com/wp-content/uploads/2018/03/SS2590.pdf

 The lack of Distortion measurements (did I miss them ?) is very disappointing, and gives no idea of whether they will have a neutral but accurate sound or not. 10MHZ Bandwidth is also quite mediocre these days .

I note that a review item elsewhere was noted as sounding a little bright, which may , (or may) not suggest a degree of HF distortion.

I have previously tried Burson discrete opamps and was not overly impressed with them either .

IIRC, the original Burson series of discrete opamps (different "flavours") were originally designed by Audio gd.

 

See also :

https://www.google.com.au/search?sxsrf=ACYBGNTHbJ6-f3QOwU22wFaFpKs-R6-7og%3A1581834243206&source=hp&ei=A-BIXsfuCcjA3LUPvu-V8As&q=audiogd+discrete+opamps+&oq=audiogd+discrete+opamps+&gs_l=psy-ab.12...2984.21169..24056...2.0..0.235.5116.0j4j20......0....1..gws-wiz.....10..35i362i39j0i131j0j35i39j0i10j0i22i30j0i8i13i30j0i22i10i30j0i8i13i10i30j33i160.g-R1ZFr9NsA&ved=0ahUKEwiH_KDht9XnAhVIILcAHb53Bb4Q4dUDCAs#spf=1581834267638

[Barton]

I can't answer your question but did ask the manufacturer to chime in. Do note there are multiple models, the one I used is the spec sheet above. 

[opus101]

@sandyk - you missed some relevant details. The unity gain bandwidth isn't 10MHz - from the plot its more like 5MHz. But that's not so relevant, what matters more is the GBW (gain bandwidth product) in the audio band - there's about 80dB gain @20kHz due to the 2-pole compensation used. To get 80dB lopen oop gain @20kHz with single pole compensation would necessitate a unity gain BW around 200MHz.

[STC]

A different kind of player. Loved by Asian wives. 
 

 

[sandyk]

7 minutes ago, opus101 said:

@sandyk - you missed some relevant details. The unity gain bandwidth isn't 10MHz - from the plot its more like 5MHz. But that's not so relevant, what matters more is the GBW (gain bandwidth product) in the audio band - there's about 80dB gain @20kHz due to the 2-pole compensation used. To get 80dB lopen oop gain @20kHz with single pole compensation would necessitate a unity gain BW around 200MHz.

I must admit that after seeing the lack of distortion figures that I only glanced at the rest.

The LME49720 for instance specifies ■ Slew Rate ±20V/μs (typ) ■ Gain Bandwidth Product 55MHz (typ) and a typical full power bandwidth of 10MHz