[Review] DIMD PP10 - valve tube amplifier

DIMD PP10 Valve Amplifier

A valve amplifier for the 21st Century?

Product name: PP10
Manufacturer: DIMD - Latvia
Cost: €3250. (Currency conversion)
(YMMV)

Reviewer: Mike Cox - TNT UK
Reviewed: April, 2017

For many years I have used valve amplifiers, their tonality is hard to resist. Some of these tube amps are second hand or occasionally new, as is the case with the review item like the PP10. They all have their wonderful sound to sell them, and usually some form of valve trait to let you know you are using a piece of technology that dates back a 100 years! The second hand equipment like my H J Leak amplifiers need careful restoration to give their best and improve reliability. Even when rebuilt they can let you down, as my Stereo 20 did a few weeks back, when an electrolytic capacitor decided it had had enough and exploded.

[PP10 rear view]
DIMD PP10 view of rear connections

Most of the modern designs I have used usually have some aspect to let you know they are an anachronism, noise or the occasional gurgle! The DIMD PP10 is the first valve amplifier that is completely silent, the warm up period is lacking drama, with no distorted audio as the valves come up to temperature and the high voltage stabilises. This truely is a valve amplifier for those who expect solid state manners. Not only is it well behaved the looks are to die for, a mixture of CNC machined anodised aluminium and wood. The DIMD team have obviously put a lot of thought into the design to make it suitable for the 21st century, even the valve covers look an intrinsic part of the design, not an afterthought like many modern valve amplifiers. Usually I like to see the valves, but with the PP10, I left the covers on as they look so cool, they get reasonably warm, but not enough to burn the unwary user or young child.

[PP10 Internal view]
DIMD PP10 view of the internals

The PP10 uses a pair of EL84s in the output for each channel, a single ECC83 as the voltage amplifier and driver, all sourced from JJ Electronics in the Slovak Republic. The power supply shuns the regular valve rectifier you will find in the older designs like my Leak Stereo 20 and uses fast recovery rectifier diodes which probably partially explains why it is so quiet. The transformers are regular I-E frame designs that are bought in along with the SCR metallised film coupling capacitors. There are no boutique parts here full of fairy dust, just good quality components well put together to deliver the best results possible.

Listening in?

The result of all this effort is a thoroughly modern design, and as I said earlier it is very quiet. At first you would not know you were listening to a valve design, it takes a little time for the amplifier to warm up and the valve magic to creep up on you. After about 20mins when everything is warmed up the PP10 starts to sing and reel you in.

[PP10 Internal view]
DIMD PP10 another view of the internals

As long as your loudspeakers are reasonably efficient (greater than 90dB/W) and not too complex a load to drive, the 10W per channel is plenty. The PP10 worked with my home made open baffle speakers that are about 94dB/W and despite the relatively high output impedance the PP10 managed to control the 15inch bass drivers. My usual reference in the bass department is Gregory Porter's album "Liquid Spirit" and liquid is a good way to describe his voice, oh that valve magic is there to thrill. The title track with that wonderful plucked acoustic bass is perhaps a little lighter and soft in comparison to some of the solid state class D designs I have been listening to recently, but still very acceptable and foot tapping.

The magic with this amplifier happens in the midrange and treble, the guitar of Paul Simon on "Hearts and Bones" is so detailed and realistic with Paul's voice drawing you into the performance. To really show what the PP10 is capable off I switched from the digital source (Chord Hugo TT and PC running Audiophile Linux) to my Revox A77, and the first generation 1/4 inch tape of the Andrea Celeste album "Something Amazing". Amazing is the result, free flowing uncompressed music with such depth and natural realism it seemed I was sitting in the recording studio with Andrea and her musicians. The results should be good, as the tapes are not cheap at €90 each for the basic version on plastic reels. The premium version on metal NAB reels are an even headier price of €270, rather a lot for a single album. I will have to save up for my next basic tape, but the results are well worth it, especially through the PP10, it is hard to stop listening.

Selecting the input with the phono stage connected, I spun up "Ella Fitzgerald Sings the Cole Porter Songbook". This album is never going to stretch the audio bandwidth extremes, but it is a good test of how well the female voice is reproduced, an important test for me. The DIMD PP10 delivers Ella in her finest voice, all the subtlety and dexterity you expect from the jazz vocal queen.

[PP10 Internal view of transformers]
DIMD PP10 view of the internally mounted transformers

Next on the turntable is Alison Krauss & Union Station on the Mobile Fidelity Sound Lab pressing of the "Live" album. This is a thoroughly modern recording well pressed on 180gm vinyl and the PP10 really shows this off, good sound stage and great musical timing. Some amplifiers and speaker combinations sound slow, but not the PP10 with my open baffle speakers. This album also demonstrates the frequency extremes well, with some wonderful finger picking on mandolin, dobro and guitar. The bass end is also well presented with plenty of slam from the kick drum. I have heard my speakers with more powerful amplifiers, with lower output impedance, deliver more slam and control at low frequencies than the PP10. The punch you get from the PP10 with just 10w is very acceptable plus you have that wonderful valve rich tone.

Conclusions

The DIMD PP10 is a real beauty with superb construction, I love the mix of wood and CNC machined anodised aluminium. Setup is very easy, no bias adjustments are needed and it is very quiet, everything you need from a modern amplifier. As long as you pick the right speakers the 2x10w is perfectly adequate. In use the amplifier delivers everything you expect, that wonderful valve sweetness from the quad of EL84s and brace of ECC83s.

With the four inputs it will meet most users needs, the only thing missing is remote control. As with all valve amplifiers you must factor in replacement valves. The EL84s and ECC83s are readily available, both types can be found for £15+, just avoid the cheap valves as you may be disappointed. Some valve aficionados love to try different valves (valve rolling), you can tweak the character of the sound to your personal taste. For me the PP10 was to my taste so never felt the need to roll the valves. I really enjoyed my time with the PP10 and it was very hard to pack it up and return to Edgars at DIMD Audio.