Hey Guys, following up with my full review.
Introduction
Hi Guys,
Today we are talking about a very interesting piece of gear from Washington state, USA. The Modwright Instruments Analog Bridge. What is an Analog Bridge you say? Good question, one I had myself at one point. Essentially, the Analog Bridge is a unity gain tube preamp, with no volume control. It exists entirely to add tubes to a solid state-based system or to add more tubes to a tube-based system, somewhere in the chain.
The Analog Bridge is a fairly hefty unit, which comes in silver or black. I have the black model here, and I think it looks great. It follows Modwright’s overall design language, and it’s fairly simple but effective in its overall design. There are two variants available of the Analog Bridge, a single-ended version, which retails for $3000USD, and the version I have here, which has XLR inputs and outputs, for $4000USD. The actual circuit of the Analog Bridge is single-ended and does not change between the versions, but the XLR version includes Jensen trasformer on the XLR inputs and outputs, which enables you to use true balanced input and output. This was a handy feature for me, as my DAC does sound better from its XLR outputs. If your system is single-ended based, or your source is, then you can save the extra $1000USD and pick up the single-ended version, as the function and sound should be exactly the same.
Tube Compliment
The Analog Bridge’s tube complement features two individual circuits switchable on the fly. You can use a circuit which features two of either the 6922/6DJ8/7309 family of tubes or a separate circuit which features two 6SN7 tubes. The Analog Bridge features tube rectification, in the form of the 5AR series, or the GZ34 family of tubes. Modwright says that virtually any rectifier tube can be used with the Analog Bridge. These tube choices allow for an absolutely vast amount of tube rolling possibilities, allowing you to tailor the sound to your preferences over time as you try out different tube choices.
For my testing, I used the stock JJ 6922, JJ6SN7, and JJGZ34 tubes. As this piece of gear is a loaner, I did not do any tube rolling as I don’t have suitable tubes in my collection to roll. If I owned the Analog Bridge, it is certainly something I would explore. From the many reports I have read about the available tubes for the Analog Bridge, there is certainly more performance to be had from pricier NOS tube options. With that being said, I was more than happy with the overall performance of the Analog Bridge with the stock tube options and would be happy to continue use with those stock tubes. The option for tube rolling is nice to have, and certainly, something you can experiment with and build up a collection over time, for different moods, music types etc…
Sonic Impressions
Overall, the Analog Bridge in its stock form (stock tubes) is not there to make a massive sonic change in the form of vastly more bass, warmth etc…It is a subtle but welcome effect to the overall sound, and I think this will depend on the individual system it is being used in, in terms of what it brings to the table. For me in my system, which is entirely solid state-based, it brought a subtle harmonic richness that just wasn’t there without the tubes, but also didn’t roll off the top end too much, or add too much warmth in the low mids. OF course, these things will be tweakable by choosing different tubes, but the overall effect I experienced was one of ease of delivery and a slight relaxation to the overall energy my system provides.
With the 6922 circuit engaged, things were slightly more linear sounding. It provided a neutral bass response with good treble extension. This circuit being engaged did bring out a slightly more holographic and expansive sound but left the overall tonal balance neutral. This will work really well with speakers or headphones that are more neutral, providing them with a bit more depth “3D” type sound over not having tubes in the chain. With the 6922 circuit engaged, the sound was less smooth than with the 6SN7, which was really great for rock, electronica, or if you were in the mood to rock out.
With the 6SN7 circuit engaged, things changed. There was slightly more harmonic richness and warmth, especially in the low mids. The bass got ever so slightly fatter, but with a bit less impact than the 6922 circuit. The treble didn’t have as much extension as with the 6922 circuit engaged but also managed to have that slight harmonic richness in the top end, which was welcome and more unusual within a Solid State based system.
Overall, the sonic effects the Analog Bridge brings (at least with the stock tube complement) are quite subtle overall, but incredibly welcome. I really enjoyed how easy to use it was, and the ability to switch between the two tube circuits on the fly. It really allows accurate and quick comparisons between the two tube types being used. With that being said, I usually would choose either tube type and use it for a whole session, vs quickly switching between the two, as that gives you more time to adjust and get to know what is being added or subtracted. The XLR inputs and outputs with the Jensen transformers were great and worked flawlessly. This was a very handy feature for me, as mentioned previously, my DAC does sound better from its balanced outputs.
System Use
The Analog Bridge can be inserted in many different places throughout a system. I always chose to run it between my DAC and amp. For speakers and conventional headphones, this meant my Rockna Wavedream DAC->Boulder 1110/1161 Pre Power combo. For electrostatic headphones, this meant my Rockna Wavedream DAC -> Mjolnir Audio Carbon CC amp. It worked great in this position in both systems, and I never ran into any trouble. You could also place it between the pre and power, or between a DAC and an integrated amp. There are tons of possibilities, it really just depends on your individual system, and where you feel it sounds best.
The build quality on the Analog Bridge is super. It feels solid and well-built, but isn’t so heavy it gets difficult to move around. I really like the black finish, but as mentioned previously, it is available in silver if you prefer a lighter colour. The tubes all sit well into the sockets, and I never had any difficulties in placing them in their sockets or removing them. The front switches are handy for switching between the two tube circuits, and choosing your input and outputs.
Conclusion
Overall, the Analog Bridge is a great piece of gear. It is simple in its overall function and application. It exists solely to add tubes to a system that may not have that option or to add more tubes for different flavours to a system that does have tubes. There are darn near infinite possibilities or tube rolling combinations to really dial in the sound to your own particular sonic preferences, but it can be used and enjoyed to the fullest in its stock form also, as I did throughout the entire testing period. If you happen to have a favourite pair of 6SN7s, or a rectifier you love, give them a try, it is certainly worth doing! The sonic changes the Analog Bridge brought to my system were subtle overall, but incredibly enjoyable in their own way, and the ability to switch between the two sonic characters via the two independent tube circuits was the icing on the cake.
If you have a solid-state system and are simply curious about tube-based audio gear, or want to get a slightly different sound character out of an already tube-based system, I’d highly recommend giving the Analog Bridge a try. I would make sure I was pretty set with the rest of the system first, and that I was already enjoying what I was hearing. This Analog Bridge simply helps an itch to be scratched, that can’t be done with other pieces of gear. It allows you to play and experiment with tube-based audio, whilst still keeping the rest of your system exactly as you like it. Overall, I’d highly recommend the Analog Bridge, especially if you are tube curious, but don’t want to go all in on a full system based around them. Great job Modwright!
