Dan Wright, the owner of ModWright Instruments is known for his passion for modifications and improvements to anything that he can lay his hands on. His products show this well, for, although they are not particularly expensive, it is difficult in to find anything in their design that we would like to change. He chooses the best possible components within a specific budget, applies the best possible enclosure, and the whole looks like a perfectly finished design. Perhaps this is why his offered devices remain unchanged for a long time with only small improvements and refinements. Besides, they can be further upgraded, such as the reviewed preamplifier which you can buy with an external PS 35.5 tube power supply boasting no less than six tubes on board!
The LS 36.5 (‘LS’ stands for ‘Line Stage’) is a good example of this thinking. It has been on offer for several years and there is no newer model to be seen round the corner. It is a linear preamplifier with entirely tube-based design and a unique Dan Wright amplification stage. The power supply is built on the 5AR4 rectifier tube and a choke. The latter works with two capacitors in a classic ‘Pi’ type filter. The capacitors are not classical electrolytes but – as in Conrad Johnson designs – foil capacitors. These particular ones are manufactured to ModWright order, with Teflon plates impregnated with oil. Similar capacitors have also been used in the signal path.
Gain stage is built on two 6H30P tubes, one per channel – the same as in BAT and Audio Research preamplifiers. This particular unit features NOS tubes from the Soviet Union times, manufactured by Reflector for the Soviet army. Currently available tubes come from Electro-Harmonix and Sovtek. Sovtek also manufactures custom branded tubes for BAT.
Dan Wright has applied them in a special system known before, but not as often used as it might seem: pure class A cathode bias ‘Mu’, with zero feedback. This is the top model preamp offered by Dan and yet its price is very ‘customer friendly,’ at least in the context of other high-end devices.

SOUND

The sound of ModWright largely reminded me of what I’d previously heard from the C-600 TAD preamplifier costing four times more. It’s a very smooth, highly-ordered sound. If I were to describe it with one word, it would be ‘noble’. This characteristic can be heard straight from beginning, from the first few bars of a familiar album. It’s like walking down the street full of people and seeing more or less friendly faces and suddenly, out of nowhere, we focus our eyes on one face that is just different from all the others. Not that it’s prettier or uglier per se, but for once it’s interesting, and two, we immediately feel that it is – just – noble. Something about defined cheek bones, balanced facial look and muscle tension or the ‘inner light’ suggests that it is someone standing out from the crowd. It is, of course, possible that when such person opens his or her mouth (as it can be male or female) the magic disappears and all we can see is only an interesting but nevertheless empty container. However, there is a strong likelihood that the conversation will only confirm what we knew from the beginning – that it is someone unlike the others. Not better or worse, just different and more interesting.
The ModWright is just like that. By no means is it the best preamp I know, nor even near the top end. We will find certain sonic characteristics that are better or much better shown by other, better, more expensive gear. I will not fail to speak about them. But yet, with each in-depth analysis, compared head to head with the best linestages I know, time after time it felt the same way – it was a noble sound.

What’s it made up of? How could this “nobleness” be characterized? The questions are clear and simple, as are listening impressions, but not necessarily is the answer. For it is primarily about feelings, impressions. These are not falsifiable, and so very difficult to verify. Therefore, in order to establish a common ground, let’s talk about all the main characteristics of the sound.
It is very smooth. Although difficult to be unequivocally classified as “tube” sound as it is not particularly warm or distinctly tangible, however, its certain coherence, fluidity between different sonic sub-ranges, its explicit continuum indicate the presence of tubes in the signal path. This is a common feature of modern audio equipment – the advantages of given technology have less in common with our stereotypical notions, and more to do with real advantages of tubes, transistors and even integrated circuits respectively. They build on their strengths, as if electronics finally matured, at least in that narrow realm.
The LS 36.5 demonstrates that nicely. While in audition I would blindly say it is tube based, that is precisely because of the fact that the sound has body, is not flat; it has excellent microdynamics, in no way associated with resolution (with which it is often confused). The microdynamics also results in a lot of things going on there, in it not sounding dull. Although image size, virtual sources are not too large, making it lack some oomph, yet both the remixes of the Depeche Mode single Personal Jesus 2011, as well as tracks on the new Assemblage 23 album Bruise – or generally, electronic music – sounded cool, interesting, had a very nice tone.

What’s it best suited for, however, is smaller groups of instruments, preferably acoustic. Not that there was something wrong with ModWright paired with electronic music; it is simply that acoustic music, jazz, etc. sounded more captivating.

That was true with the new remaster, originally released by Telarc, of After Hours by André Previn, with Joe Pass and Ray Brown. It’s a powerful performance, with closely shown instruments, especially bass. The mastering highlights the midrange, which is slightly contoured, somewhat explicit. The American preamp showed it well, without any thinning out or rounding off the attack. Even if a slight softening could be heard, it was barely on the edge of perception and even then not as a flaw but rather an inherent aspect of that “nobleness.” However, there was nothing to dwell on; it was simply a good sound, even more so as the tone color of individual instruments was very well differentiated, and the guitar nicely blended with the piano without homogenization, each maintaining own essential character.

As I said, I couldn’t detect any thinning out of the bass. The same was true with albums by McCoy Tyner, Sara K. and e.s.t. There was no tone coloration or rolling off the frequency response. The double basses had clear low end as did the pianos. If it was limited during the recording and mastering stage, as on the Tyner’s album, it was presented as such; similarly, the broad spectrum on the e.s.t. album was immediately heard. Differentiation was really top notch.

However, it needs mentioning that something is not quite right in the bass department, something that more expensive preamps are largely free from. The electronic music albums but also Offramp by Pat Metheny Group showed something that needs our attention – a slight reduction of image size, some shrinking of virtual sources. That was the reason why the albums sounded lighter than they did e.g. with my Ayon. They had less oomph, tangibility. It was still good sound, definitely high end; very real but not so strikingly realistic.

It also translates into a slight distance with which the sound is reconstructed in our listening room. Soundstage is not spread out and music is located in its center. Items placed there by the sound engineer are dominant, leading. Such was the aforementioned double bass on the Previn’s album, shown in a clear, slightly contoured manner.
And these are the two main differences between the ModWright and more expensive preamps, which we can pinpointed. Other minor distinctions, like slightly less vibrant cymbal crashes, etc., are subtle and not worth our attention. You can forget about them.
All the more so that it is the midrange and the treble that demonstrates everything the tubes are known and loved for. It is a seemingly quasi-soft sound. Seemingly, since the punch was there, strong and clear, but without sharp edges or irritating grit seen with both solid-state and tubes. ModWright can be described in different ways, but certainly not as dry, bright, or even light sounding. It is a slightly warmed, quite fleshy presentation. The unit is very nicely built. The signal path is short which translates into fantastic microdynamics. Differentiation is ikewise excellent. And the price – in the context of other preamps reviewed in this issue of HF – is simply unbeatable. It’s a really cool, high quality sounding piece of gear.

Testing methodology
The ModWright LS 36.5 was compared against my reference preamp, the Polaris III [Custom Version] from Ayon Audio, as well as other linestages reviewed for this issue of “High Fidelity”: the Audio Research Reference 5 SE, the Soulution 720, the TAD C-600 and direct coupling of my Ancient Audio Lektor Air V-edition CD player and my Soulution 710 power amp. The LS 36.5 drove two power amps – the above mentioned Soulution 710 and the Leben CS-1000P. Harmonix X-DC350M2R Improved-Version power cord and it was seated on the Franc Audio Accessories Ceramic Disc spacers, and the Base IV [Custom Version] rack.
The testing had a character of A-B comparison with A and B known. Music samples were two minutes long. I also auditioned whole albums. Coupling was via RCA unbalanced cables – both on the source and the power amp sides.

The amplifier receives the RED FINGERPRINT award.

DESIGN

The LS 36.5 is a tube preamplifier with tube power supply. The circuit is a zero-feedback, class-A cathode bias Mu-type with a 6H30 dual triode per channel in gain stage. The output is transformer-coupled. The input is coupled via large custom built Teflon foil, oil-impregnated capacitors. Interestingly, the ModWright seems to employ a hybrid JFET/tube circuit topology. A similar topology is used by Audio Research.
The design is exceptionally well thought-out with the signal path section constituting only a part of what’s inside. The power supply section is huge and is separated from the rest by an aluminum shield. It is built around a massive toroid transformer with several secondary windings. Anode current is rectified in a full-wave Ruby 5AR4 tube rectifier, carefully measured and selected. On the manufacturer’s website we read about a recommended upgrade to the GZ34 from Mullard, Amperex or Philips. The current is filtered in the choke loaded CLC filter. Voltage regulation, really complex, is solid stage based. Filament current is also rectified. The signal from inputs is directed to with switching relays. The potentiometer seems to be not in the input stage but rather between the triodes – it is a large, motorized blue Alps pot. The inside coupling is via copper wire – shielded to the potentiometer and unshielded for other connections.

The entire enclosure is made of thick, rigid aluminum plates. The front panel is especially thick with a deeply engraved company name, a large logo and all switches descriptions. We can rest assured that nothing will wear off even after 50 years of LS 36.5 service.
Centrally placed on the front place is an input selector knob. There are five inputs – four unbalanced RCA and one balanced XLR. However, the device seems to have unbalanced circuit topology. A volume knob is located to the far right. Between the two knobs we have three large toggle switches – Mute, Phase and HT / BP. The first mutes preamp’s output, the second inverts absolute phase (polarity) and the third activates through-out for an external home theater processor. Above the two outside switches there are large, blue LEDs, and above the middle phase switch an IR receiver. The LS 36.5 is remotely controlled. A small but friendly remote with membrane buttons controls volume, absolute phase inversion and mute mode.
The far left of the front panel features another toggle switch with a blue LED, for mechanical power off (no standby mode).

The back also looks nice. XLR ports are from Neutrik and RCAs seem to be from WBT – solid Teflon insulated locking connectors with great looks to boot. Of four outputs, one is fixed RCA and three are variable (two pairs of RCAs and one XLR). The whole picture is rounded off by an IEC power socket, a small toggle earth switch, and a plugged socket for an optional external power supply unit.

The unit rests on small rubber feet and they are about the only thing that needs changing. Overall, it is a nice, clean and solid piece of workmanship.