First Watt SIT3 vs Dynakit ST35

For this comparison we used a Custom 6SN7 Line Stage by Don Sachs with various jazz tracks as well as classical. For speakers we used a pair of Lii Audio Silver 8 and F15 open baffle speakers run in parallel along with a 15" Caintuck open baffle sub. For the ST35 we would use the 4 ohm taps. The room is about 15x10 and well damped. If you clap your hand, there’s no audible echo. As some of you may know, I already compared the popular Decware SE84UFO Zen to the SIT3 here in the forums.

Next, I wanted to compare the sound signatures of the Dynakit ST35 to the First Watt SIT3. The ST35 took about three weeks for Kenny Russell of Funtastic Vintronics to complete because he was awaiting a few parts. The ST35 is based on the EL84 tube and mine has a matched set of quads, the Baldwin EL84’s along with a pair of Mullard’s from Great Britain on the front end. I normally like working with Kenny because his work is super clean and he’s very detail oriented. The others mentioned also do very nice work.

First, just some things to know about me. I’m one of these listeners who doesn’t care if products are not popular or well known, in fact, I mainly prefer to review less known components because there’s just way too much of an abundance of mass production amps coming from China with overly sparkly sound and excessive analytical top end. This may sound exciting when you first hear it but gets old and fatiguing after a while when listening over time. And, if you’re gonna go that route, then you may want to be careful what speakers you are selecting so the top end isn’t too fatiguing over long periods.

People often have a terrible habit of behaving like sheep, so I make it a direct point to avoid being one as much as I can and I avoid hype with a passion. For example, I don’t care much for all these YouTube stars trying to gather subscribers when in fact it’s the guys behind closed doors who are the real geniuses and most sadly go unknown to the crowd. Why? Because devoted technicians and good reviewers are usually not just reviewing marketed products and as some of you already know, I can’t stand marketing. It sways people into believing things that are often very misleading. It reminds me of pedestrians who decide to cross red lights. One person does it, so the rest decide to do it. In the end, it’s the wrong thing to do.

The guys that you don’t hear about are often the ones I want to know more about. For example, Will Vincent, Don Sachs, Kenny Russell, Holger at Erhard, Alan Eaton and Dennis Had to name a few. So, if you love tube amps and truly have a genuine passion to know more, all these YouTube stars is the wrong place to get your info from. I’ve said this before and I’ll say it again, look at Kevin’s site at Glow in the Dark Audio here for real honest to goodness reviews from someone who really knows more on this particular subject than I ever will.

Most of the gear these YouTubers boast about is being fed to you in huge quantities via products being shipped in from China and that’s about all these YouTubers review. They know little to nothing about these beautiful unique, hand made tube amps on Kevin’s website. Google these amps with the YouTube stars and see for yourself. You’ll find absolutely nothing. To me, it’s a total shame and a sham, devised to amuse a mob with the soul agenda of getting subscriber counts in order to make a living and I have no qualms for others wanting to make a living at things. I just won’t do it at the cost of marketing others when I know for a fact there are other amazing products being made here in the US. Yes, I’m aware that some of the parts may be sourced from China, but at least if you consider these hand made amps, you have a good opportunity to speak and learn from the individuals who take the time to make them. They pour their hearts and souls into building something nice for you personally, and I believe they deserve far more credit. Sadly this industry is exactly like the industry I work in as a profession and fortunately, I can see through all the smoke.

Personally, I tend to like Steve Guttenberg because at least he expresses some heart and soul. His videos are not devised to make everything enticing and commercial-like to the eyes and mind. He seems like a pretty straight up character with a genuine interest along with an array of music choices. He’s been in the business for several decades and seems pretty sincere and level headed to me.

So, now that I’m done with my soap box rant, I’ll get on with this comparison. The ST35 is clearly one of those components nobody knows much about and that is truly ironic to me. How did this tiny amp slip under the radar undetected? It’s a great mystery to me and one I don’t think I’ll ever understand. If you do a Google search on the ST35, there is absolutely next to nothing on this amplifier other than a few exchanges, nor are there any videos on it other than a few demos and someone building them. So, it appears nobody is really reviewing the ST35 and to me that is such a shame.

With regard to the First Watt, one of the things that’s quite cool about them is that they really do tend to sound like tube amplifiers even though they are solid state. I have generally found the SIT3 to have a slightly thicker and darker sound compared to the F3. I actually prefer the F3 over the SIT3 even though for some reason the SIT3 tends to be more popular and far more pricey. A used and discontinued F3 will set you back about $1400 while the SIT3 will be just under $4000 on the used market. The F3 is an incredible bargain.

To me, the F3 just seems to have a bit more finesse up top while the SIT3 sounds a bit more brawny and muscular. Brawny and muscular may seem more attractive at first but what I have found is that it doesn’t sound quite as refined when hearing the delicacy of individual string instruments or harps for example. It tends to give string instruments a thicker bodied sound signature that tends to remind me a bit more of solid state than tubes or compared to the F3. For open baffle however, which tend to have a thinner or less meaty sound to them, the SIT3 can be a great match and perhaps even more so than the F3 to balance things out a bit. So, in my opinion, I think it all has more to do with matching the components to the speakers rather than just blanket statements that this model is better than that model. I still just happen to prefer the F3 personally.

One of the things I struggled with regarding the Decware Zen when comparing it to the SIT3 is that when turned up to slightly louder levels of 85db or more for example, there were "sometimes" issues where it would run out of steam, relative to the SIT3 which basically retained a slightly larger soundstage at higher volumes and handled quick bass when called upon more cleanly. The Decware sounds more refined up top though. This is where the ST35 came in and basically threw us for a loop. Think about a tube amplifier that has all the qualities of a Decware Zen but has far more power, bigger soundstage, tighter and cleaner bass when called upon, and an even warmer and sweeter sound. A sound that makes harps sound like silk and sounds that are even more balanced than a Zen. That’s what the ST35 does and then some. Even my friend who owns the SIT3 was dumbfounded just as was, not to mention that this little guy is only $1300 fully assembled, brand new.

At a different listening room we call the Rim, I told my friend Bob that I didn’t know if the ST35 will be enough juice to fill the room. The dimensions of the room are about 25’x15’. In this listening area we have a pair of Lii Audio Silver 8’s in parallel with a pair of Lii F18 open baffle speakers and a 15" Caintuck open baffle sub. Coupled to an Erhard Aretha preamp. We were absolutely shocked that the tiny ST35 filled the entire room with plenty of meat on the bone and even more room to play at higher levels than expected and not only that, it sounds huge. It doesn’t sound like the tiny amp it is. We were absolutely astonished at the performance of the ST35. It’s so tiny, yet it just has a tsunami of weight when using efficient speakers compared to all the others.

I normally don’t sell amplifiers and change amplifiers in search of the holy grail. I just normally collect a few and use them for different moments of listening. All that happened was that I had always wanted a tube amp that had about 8 to 20 watts and I stumbled on the ST35 by accident and gave it more consideration since nobody seemed to know much if anything about it with the exception of a few audiophiles. Since I already had the Bob Latino ST70 and used the Will Vincent ST70’s, I will tell you that this is entirely different. Will Vincent offers an ST35 but it uses the much larger chassis of the ST70 which I’m not as keen on and I think it's set up in triode mode. The model Kenny Russell made is set up in ultra-linear mode and in my opinion should produce a slightly fuller sound. I couldn’t say for sure though as I have not yet heard the Will Vincent version, but my friend has one which I am intending to have a chance to hear. He uses a pair of Klipsch LaScala’s but he doesn’t yet know if it will sound anything like this version I have now.

The original ST35 was highly regarded for the metals used in the transformers but these newer transformers may be even better. So, now I’m in a situation where the ST35 is producing sounds I find even more favorable to my ears than many well respected amps such as the Alan Eaton 45 monos, Primaluna Evo 400, Decware Zen, First Watt SIT3, First Watt F3, Will Vincent ST70, Bob Latino ST70 and many others too long to mention that Bob and I compared over time. The vast majority of my comparisons were done using the Aretha tube preamp by Erhard Audio. I think I’ve had this device for quite a few years now.

Why is this ST35 so amazing to me? Because this ST35 has the most unique sound signature I’ve ever heard in any amp I’ve ever listened to. It has all the soundstage, bass extension, balance, sweet, silky top end, tight bass, balance, darkness all in one complete tiny package and just one more thing that separates it from all the rest. It is by far the warmest sounding and it’s very audible in ways I just absolutely love. Todays modern tube amps are far from warm. They’re actually quite bright sounding. When someone tells you tubes are warm, I can honestly say the ST35 is definitely one of them. Without question the ST35 is the finest sounding Dynaco amp ever made and not by a little, but by a mile in my opinion. The ST70 is nice, but compared to the ST35, the ST70 sounds more grainy and less balanced. It's also brighter by comparison. When the ST35 is coupled to efficient speakers, say 89db or more, it works amazing, even with 4 ohm speakers. It produces the prettiest, "warmest" sound signature by far then any other.

At one point I was listening to jazz like Scott Hamilton and Wes Montgomery from 3pm in the afternoon till 6am the following day. This ST35 is like a serious drug addiction. The most significant thing you will get from this is its sweet, silky sound signature which is more than anything I’ve ever tested to date. Sax, trumpets don’t shoot out at you like other tube amps that are more colored. They come at you more subtle and at first you may think it’s not as exciting, but when you keep listening to it, it just sucks you in more and more because it’s so dang pleasant to listen to, especially when listening to jazz. During a recent session with my Klipsch Forte 1’s, I was playing Charles Mingus "Better Get Hit In Your Soul" on vinyl and there are some very subtle voices in the background. When I first heard them with the ST35 coupled to my Aretha, it scared the living c....p out of me. I could swear I heard the voices were coming from behind, over my right shoulder and I thought they were voices at my front door from the position I was seated. A totally three dimensional experience.

Always remember that many of todays modern tube amps are designed to be very analytical in sound. So, when you first hear an ST35, just remember that individual instruments don’t just shoot out in your face. Instead, they will take on a more relaxed rendition that’s completely holographic in nature and I will say that for longer listening sessions, the ST35 is by far, the most pleasing amp I’ve ever compared or tested to date. This explains why I enjoyed listening for 16 hours straight. I was dead tired the next day. If you own any type of efficient speakers, combined with a good quality preamp, you will be in for a very pleasant surprise. I was so impressed with the ST35, I ordered a second one for my other Heritage speakers and sold all my others. Why? Because this can do everything that’s needed, all packed into one, sweet little package and it delivers it in spades. So far the ST35 is my favorite amp of all time. For those of you willing to wait more than a year for a Zen, to me it wouldn’t matter if a Zen was available tomorrow, I still prefer this little ST35.

Happy Listening!




"I will say that for longer listening sessions, the ST35 is by far, the most pleasing amp I’ve ever compared or tested to date. This explains why I enjoyed listening for 16 hours straight. I was dead tired the next day. If you own any type of efficient speakers, combined with a good quality preamp, you will be in for a very pleasant surprise."

Agree completely. I have an ST35 built by Kenny. His work is superb. In the audio world, this amp is a true bargain, a classic EL 84 amp. Dave Gillespie measured the new transformers and they exceeded the specs of the originals. I'm driving Klipsch Heresy IVs with an Inspire preamp from Dennis Had, and they are a great match.


I've always had a soft spot for the ST35.

I seriously considered finding one or building one up from scratch when I was looking into an amplifier for my bedroom system. But I realized it would be too large both power and size-wise so I built a smaller amp based on the EL95, a tube with which I was unfamiliar until rebuilding an old Grundig stereo console for a customer. A pair of them makes only 5 Watts in class A but that was fine for my purposes.

The EL95 was meant to be very easy to drive. The Grundig console power amp used 12AU7s as a result- even for the voltage amplifier. I my design used a single 12AT7 wired as a differential amplifier, allowing me to use the second grid of the tube for feedback.

I've considered building an EL84 amp using the ST35 magnetics since they are arguably some of the best ever built and one reason why the ST35 is so good (the output transformer is nearly always the bandwidth limit in any tube design). The EL84 is nearly as easy to drive so the 12AT7 circuit I came up with seems like it would be effective here as well.

The original ST35 employed a 7247 which is a dual triode using single 12AX7 and 12AU7 sections in it. The 12AX7 section is the voltage amplifier. The advantage here is being an all-triode voltage amplifier and driver, the linearity is quite good. This is really important when using the limited amount of feedback that the amp employs.

When the feedback arrives at the cathode of the 12AX7 it is distorted slightly by the tube itself. This causes the feedback to add some distortion of its own (and is why feedback often has a bad rap). By using a more linear tube, Dynaco was able to limit some of the damage that is often caused by feedback, resulting in a very musical amplifier that is also quite neutral. They used a pentode gain stage in the ST70, which distorts the feedback more, requiring more feedback to get around the problem thus created, and unsuccessfully IMO, although the ST70 was quite competitive in its day and is still a good amplifier if rebuilt properly today.

The 12AT7s circuit I mentioned above is actually a bit lower distortion owing to its differential nature. Its a bit simpler, although it requires a minus power supply not present in the original amplifier.

@rankaudio I'm not familiar with the rebuilt version you have. Does it still use the 7247 driver tube like the one by him I saw on YT? If so where do you get the tube?

I agree with the OP about First Watt F3s.  They are splendid amps for those of us with very efficient speakers.  I use two F3s to power the midrange and super tweeter horns of my DIY fully horn loaded triamplified speakers.  The F3s replaced Cary Audio 2a3 monoblocks and the change wrought a great improvement in SQ.

Thank you Daniel. It's such a pleasure to hear how people are enjoying the amps I build for them. Looking forward to your next order......Kenny, owner @