Saturday, July 11, 2020

Musical Paradise MP-701 Mk II Tube Preamp

Introduction

Musical Paradise is a cheerful company that serves up tantalising components to audiophiles on a modest budget. According to their website, they state the following, "Our mission is to design and manufacture high quality audio equipment to fulfill critical audiophiles' demand with competitive prices." 

This is the first Musical Paradise product that I've owned and so far I have been impressed by their innovation, quality of build, sound quality and totally outrageous value-for-money. 

Description

Looking like a very tall oversized shoebox, the MP-701 Mk II measures 31 cm (W) x 39 cm (D) x 14.5 cm (H). Construction is really good, with a solid aluminium alloy faceplate and panels. Weight is a reassuring 12 kg. 

The MP-701 Mk II is said to be the product of two years of research and development. It is a three tube design with zero negative feedback. The power supply is tube rectified. There are plenty of conveniences, including XLR sockets in addition to the usual RCA sockets, as well as a remote control.

Parts quality is very good throughout, with a 150 W shielded toroidal transformer, Vishay resistors, Nichicon and Rubycon electrolytic capacitors, and Obbligato Gold film coupling capacitors. There is also an option to upgrade the coupling capacitors to Mundorf Silver Gold Oil capacitors for a premium.   

This is the point where the usual list ends and things really get interesting. 

Want to roll your own capacitors but don't know which end of the soldering iron to hold ? No problem, just undo the binding posts and change the capacitors yourself. 

Can't get the gain matched properly in your system ? No problem, just change the gain settings by flipping a DIP switch. 

Want to roll different tube types ? No problem, change your preamp or rectifier tube heater voltage settings by accessing a switch too.

Here is a list of rectifier and preamp tubes that can be used in the MP-701 Mk II :-

Rectifier tubes

6.3 V - 6Z5P, 6X5
5 V -  5R4, 5U4G, 5AR4, GZ33, GZ34, 274B, 5Y3, 5Z3P

Preamp tubes 

6.3 V - 6N11, 6N1P, E88CC, E188CC, CCA, 6922, 6H23, 6H6, 6H30, (6SN7 with 6SN7 to 6922 adapter).

12.6 V - 12AU7, 12BH7, E80CC, (12SN7 with 6SN7 to 6922 adapter).

Don't forget that as each rectifier type has a different voltage drop, the resulting plate voltage will also change. As this shifts the operating point of the tube, the rectifier choice will alter the sound. This means that the possibilities on tweaking the sound are endless ! Similarly, you can get a more classic tube tone with tubes like the 12AU7, or a more modern and linear sound with the 6N1P or 6H30 tube.

Both the two output coupling capacitors and two film capacitors that bypass the main electrolytic power supply capacitors are mounted on speaker binding posts that unscrew to allow easy replacement.

Impedance is specified at 100 Kohms (input) and 2 Kohms (output) with a recommended pairing with a power amp with a minimum 10 Kohms. I personally think that is a bit too liberal, and at least 47 kohms may be more appropriate.

To be continued ...