[Listening test] The Truth Pre Amp

The Truth Pre Amp

An innovative approach that delivers high performance and low cost

Product name: The Truth Pre Amp
Manufacturer: The Horn Shoppe - USA
Cost: $1020. US. for 3 input model (Currency conversion)
(YMMV) Reviewer: Roger McCuaig - TNT Canada
Reviewed: November, 2018

Introduction

I learned of the existence of this product from Arthur Salvatore. After exchanging some emails with him I decided that I needed to try it. I made the decision to purchase The Truth Pre Amp instead of going the review sample route as it seemed to be a perfect fit for my system. Now, almost a year later, I can say that it would be very difficult for me to replace this component in my system. So, my challenge is to explain to our faithful readers why I feel this way.

What is The Truth?

The Truth was designed by Ed Schilling who operates through a web site called The Horn Shoppe. This is a very small operation, Ed and his dad, working out of his house in the Leesville, South Carolina area. The Horn Shoppe has been in existence for many years, in fact, some of Ed's speaker designs were reviewed on this web site as far back as 2001. The Truth Pre Amp was created in 2010. The basic design objective of The Truth can be described as; provide basic pre amp features while doing the absolute least amount of damage to the signal passing through the device. Tubes, solid state devices, resistor, capacitors, and even wire add noise and distortion to an audio signal and subtract content from that signal. Logically, putting the smallest number possible of these components in the signal path should lead to the least distortion and noise. This, of course is a vast topic and design choices are endless. This review will not go any farther down that road and simply state the problem.

There is very little design information on Ed's web page so the following description has been cobbled together from various sources and discussions with Ed and from opening the box. The solution proposed in The Truth is to eliminate amplification, to implement volume and balance control using light and to use input and output buffers to optimize impedance for the source and for the amplifier. The Truth provides attenuation only thus eliminating all of the amplification components. More on the consequences of no amplification later. The result is that there is only an input buffer, a photocell and an output buffer in the signal path of each channel. Volume and balance control are done using light. The volume and balance control pots are not in the signal path. The rest of the signal path is a short length of wire and in my case the signal wires are VH Labs OCC copper and OCC silver. Present thinking of designers is that best results are achieved when the input impedance of a given component is much higher than the output impedance of the upstream device. The Truth input buffer provides a very high impedance as seen from the source whereas the output buffer provides a very low impedance in front of the amplifier. This is claimed to be a key element of this design as it rectifies one of the main problems associated with passive line stages, the inability to conserve the life in the music. I personally used a good quality passive line stage for over a year and finally switched back to an active one. I missed the energy. See my review here.

A look inside the box reveals a light source the intensity of which is controlled by the volume pot, and 2 photocells, one for L and R channels. Initial channel balance is accomplished at the time of fabrication simply by adjusting the distance of each photocell from the light source while the fine tuning is accomplished with the balance pot. I presume that the balance pot functions by adjusting the sensitivity of the photocells. I don't have any details on this. A consequence of this configuration is that the balance knob is not necessarily centered when the balance is centered. If this is a problem for some people, one solution is to adjust the balance to as close to centre as possible and then unscrew the balance knob and reset the index marker as you like. I would certainly not recommend opening the box and tinkering with the photocell positioning unless you are willing to live with the risk of damaging the unit. In my case the balance was way off when I received the unit, Ed believes that it must have been subjected to some severe impact during shipping. I have not tried to adjust the photocells but I did recentre the Balance knob. From right to left in the photo above: Input Buffer, Optical control board, Output Buffer, 2 power supplies.

No Amplification - The Bolero test

The Truth Pre Amp can only work properly in a system that plays loud enough for your listening habits with no amplification in the pre amp stage. If you are not sure that this is the case for your system there is an relatively easy test that you can perform to find out. To the best of my knowledge, this test was originally proposed by Arthur Salvatore. Be warned, if you are not confident in what you are doing get some help, you don't want to damage anything. The test consists of connecting your source device that has the smallest output signal, in my case that is a turntable/phono stage, directly to your amplifier, thus bypassing your amplified preamp stage. Now you need some music that starts off at a very low volume and gradually builds up to very loud. Of course the ideal selection is Ravel's Bolero. If Bolero plays well and you get to your required loudness level before you get to the end of the music, then The Truth should work in your system. In my case it only takes 0.72 volts input to my Canary amplifiers to produce 100% output and my speakers are around 97 dB/W so I have lots of volume. You could be at the other extreme of the scale with 2.0 volts and 80 dB, these are common values. In which case you may not be able to forgo amplification in your pre amp stage. Especially if you like loud music.

Caveat Emptor

Each unit shipped by The Horn Shoppe is built to order. You need to clearly indicate what you want in your communication with Ed. Some of the things that need to be specified are:

1 input or 3 inputs
Single or dual power supplies. The base design at the time I ordered my unit was single. My unit has dual and this may in fact be the standard now.
Standard copper wire or VH Labs OCC copper or silver wire.
Single or dual outputs. The Truth is designed to power two devices. The web page states "It can run 2 outputs". However there is only 1 set of output connectors provided unless you ask for 2. I am biamping so I had to purchase RCA splitters.

A buyer should ask a lot of questions before the unit gets built in order to avoid any surprises. The above is not a complete list. I believe that Ed can accommodate quite a variety of needs or wants.

Put to the test

The Truth comes with a one page Quick Start Guide. This document provides a step by step procedure for operating the unit. At the bottom of the page in double-sized font is the following: “Do not run it on an unused input, always make sure there is a source connected to the input in use.”. It doesn't say anywhere what the consequences might be for ignoring this directive but it got this new owner nervous enough to connect devices to all 3 inputs even though I only use 2 of them!

My first few listening sessions were a bit disorienting. I was not quite able to put words to my impressions. It took me 2 or 3 days of heavy listening time really start to be able to answer the question “What am I hearing?” I have concluded, and I am still comfortable with this conclusion many months later, that the strangeness was due to the lack of noise and distortion. An impression of something missing. With The Truth Pre Amp not only must one ask “What am I hearing?” but equally as important “What am I not hearing?”. There is a purity to the sound that surpasses anything that I have experienced. If one removes the noise and distortion produced by a typical amplified pre amp what's left is the music! The initial disorientation gave way after a few days to a desire not to go back the the original setup. Imagine a product that combines the purity of a high end passive pre stage (except better), with the dynamics and vitality of an amplified pre stage.

One of the first concrete characteristics that I noted was the speed; things like attacks on notes, are ultra precise. Quite logical really, if one removes about 95% of the components from the signal path. On Paul Simon's Graceland the tic-tic sound in the background acquired shape and body and a 1 second decay time. Street Fighting Man from Beggar's Banquet was a standout because of the clean and precise rhythm guitar. The wonderfully low sound floor brought out the best in good recordings and of course exposes the flaws on others. Waiting for a Miracle (Bruce Cockburn) was breathtaking, I have never heard this record sound near as good. Simply a magnificent recording. More detail in the background was a constant thread through all of my listening time. This was noted on too many recordings to mention.

Some issues with the product?

As one can see in the photos this unit has a home-made look to it. There aren't even any labels on the controls or the connectors! Compared to, for example, my Canary amps, this unit is shockingly primitive. Ed could have gone another route as other small operations have done by farming out fabrication and supply of components and sub assemblies to specialized suppliers. This option makes any level of sophistication available to even the smallest company but the price for this is quite steep. One could easily imagine double or triple! So, to those who are impressed by bling or buy components based on trying to impress their buddies with cases machined out of a solid block of some exotic metal, this unit is not for you.

When the unit arrived one of the first things that I noticed was the bizarre collection of control knobs. There are 3 knobs on the unit; Source, Balance and Volume. On my unit, all 3 were of different shape and size and looked like what one would typically find in the bargain bin at Radio Shack in the early '70's! Seriously? After a few weeks of use I placed an order at a parts supplier for 3 identical, modern looking, quality knobs. As mentioned in a previous section of this report, some type of upgraded boxes and knobs etc. may be available upon request. I am tempted to ask “Ed, do you really want your superb product out in the world dressed like this?” but I already know the answer to that question, one of the original design parameters of this product was to keep the cost as low as possible.

Conclusions

One of the first things I wrote on this web site was “No matter how good your system is, there's probably something you can do to improve it” and The Truth Pre Amp was for me another proof of that statement. My excellent Doge 8 pre amp is now bypassed and I am now only using it's phono stage. The Truth injects less noise and distortion into the signal path and drops the sound floor making the music sound more alive, detailed and revealing and it does all this while avoiding the achilles heal of all passive line stages which is the inability to conserve the life in the music.

I am not at all aware of the history of this approach to pre amp design and it may in fact be a revolutionary product. Similar concepts have been explored in the past but it appears that this product is the first one to implement volume control using a photocell. (as opposed to an opto-coupler for example) I think The Horn Shoppe's niche market is safe. I can't see any big name companies being interested in building pre amps with such a small component count. There isn't enough profit margin to be worth the effort. Furthermore, how does a company that sells $10,000. pre amps explain that the $1000. photocell unit sounds better?

The bottom line is simple, this component will improve the sound of any compatible system. One must simply accept to live with the low budget look and feel of the unit. At the $1000 asking price its worth the investment for all but the most low budget systems.