Guest Post by Larry Kennelly
A couple of weeks ago I received a call from a friend Dan that he was building an Elekit TU-8300R DIY tube amp from a kit and, would I like to join him. Admittedly I was a little curious and took him up on the offer. I can do some basic carpentry, change the brakes on a car and would call myself mechanically inclined. Having said that, I have little or no experience with electronics and am not an audiophile. Conversely Dan is all of the above; versed in electronic gear, mechanically inclined and an audiophile.
When I arrived he had begun the process of stuffing and soldering the first couple of circuit boards. Over the course of about an hour I was invited to solder some of the pieces that Dan had been working on. My last experience with soldering literally was on a pipe and I almost burned my house down. Fortunately for me the amp’s owner is quite proficient in electronics having built his own line of professional studio gear some years previous.
Dan had taken the time to lay out the various components in a way that made them easy to identify and find. This is not a strong point of mine but I could see the value of a little advanced preparatory work. When instructed I was able to identify and find a capacitor, diode or resistor as instructed.
Within a short period we had a Tom Sawyer experience happening and I was leading the charge. Finding pieces, installing and soldering them in, I very quickly saw a pattern. Each of the symbols for the type of component was printed on the board. Consequently, it was difficult to put a resistor in where a capacitor should go and so on. Parts that had to go in a particular direction were well marked on both the circuit board and the parts themselves. And to my surprise things fit. The first two boards were essentially mirror images of each other and became increasingly interesting as time passed and they were populated. I found this so mesmerizing the hours flew by. In total I would say it took about 6 hours to populate and solder the circuit boards. An hour of that was spent fixing a couple of minor misplacements, which were quite obvious in hindsight. Little things like putting a diode in backwards, when it was clearly marked and missing a couple of capacitors was simple human error. The great thing about this build is the fact that each piece is identified in the directions and provides a check box when completed. Finding the problem was very logical during quality control as I did in fact have a couple of unchecked boxes on the parts list.
Assembly of the components on to the chassis is where you start to feel it coming together. Each component made it look more and more like a functioning piece of gear. Most of the assembly up to this stage can be easily accomplished with one person. However, an extra pair of hands is useful at this point as assembly requires working from both sides of the chassis and there are elements of working blind. I’m certain it could be done alone by a more experienced person but I found it easier to assemble the boards in the chassis and make the final connections with another pair of hands and eyes. One final QC run to ensure there were no remainder parts or unsoldered connections.
Finally it was time to hook it up, plug it in and hear how it sounds. The amp came complete with Shuguang 12AT7 and Shuguang 300B-98 vacuum tubes but Dan felt some Mullard 12AT7WA / CV4024 tubes would provide a warmer sound and a pair of Northern Electric KT88’s. We chose to use a digital streaming feed and then a pair of Wathen Inertia Cube speakers that we just picked up at NAMM. The lights came on, check. The tubes lit up, check. The volume control worked, check. Now beautiful sound was coming from this single ended amplifier. I must admit that the sound was made all the more rich by the fact that I had a hand in creating it.
In summary I can say it was a pleasure helping to build this amp. The instructions were clear and comprehensive enough not to confuse. In spite of the fact that I was not the lead builder of this project, I do believe that I could build this alone, albeit more slowly. The amp resembles the picture and sounds better than I had expected.
As an end note I should mention that this amp was custom powder coated, a metallic candy apple red, by a local business in order to suit the preference of the owner.
As the owner of thetubestore.com I wanted to test build one of the new amplifier kits we are carrying from Elekit. I built my first ever amp with a kit from Heathkit approximate 30 years ago and have been building, designing and repairing tube audio gear ever since. I felt a better test would be to have a complete neophyte give it a try to see how well this came together.
Our build time took longer than usual primarily because I chose to have my chassis powder coated in metallic red. This filled all the threaded holes used for screwing the whole assembly together. Each hole had to filed ever so slightly and carefully and then re-taped with a screw prior to assembly to take out the excess paint from the threads. This added a lot of extra time over using the normal kit chassis. Elekit states a build time is 8 to 10 hours but ours took significantly longer due to the powder coating and correcting build errors. Our total time was approximately 15-16 hours. I’m very impressed with the instructions, the extra parts supplied and the final result.
The amp is now at home with me using our Northern Electric KT88 power tubes and playing through some high efficiency Cain and Cain Abby speakers and Baily sub. After three days my observations are this amp has plenty of power and wonderful tone. This amp holds its own against much more expensive brands we all know. I think it’s a steal for the money and will leave you feeling rather smug knowing you built this! I can absolutely recommend this to anyone wanted a great sounding and versatile tube amp.
What I really love is the ability to use so many different power tubes without any need to re-bias and make other adjustments. Just plug and play a 6L6, EL34, KT66, KT88 or a 300B! Not many amps can roll power amplifier tubes like this.
I had to comment on this. Your blog post gave me a smile! Looks like my ‘original’ ain’t so original any more. 🙂
I’ve built up a couple of these for players. Had to put a brace across the cabinet to take care of vibrations but for sure we’re on the same path.
Can this kit be modified so that it can use 6A3 type tubes in place of the 300B tubes?
No, at least not easily. It’s built on a PC-board so modifications like this would be quite difficult. Some type of socket adapter would be an easier way to go.
Great article , when I was in my early 20’s I tried to build a Dynaco preamp kit , I must say that for someone who couldn’t even solder properly I didn’t do tooo bad , nonetheless it never worked properly and a local HiFi shop had to fix the problems , at a cost ….
BUT , my actual question , does this kit come for only 110 Volt ?
I’ve built a Dynaco kit too. By comparison the Elekit comes with better instructions in my opinion.
Regarding the power transformer, it is universal (100V, 115V, 200V, and 230V). You’ll find the specs listed on our site.
Can I change all transformer(s) to the box type and are they available for sale and how much?
For critical audiophiles, the TU-8300R amp kit is an amazing platform to build up from. Although it sounds great in stock form, the unique output transformer mounting brackets Elekit devised allow you to upgrade to many high-end output transformers to suit the listeners taste. Tango, James, Tamura, and Hashimoto all offer fantastic options. Virtually any transformer that has a 2.5K to 3.5K input impedance, rated for 10W or more will work well.
If you download the assembly manual you’ll find the power transformers specs on page 20 shown on the schematic. Although it’s likely an alternative power transformer could be used, I suspect mounting it would be a challenge and require some drilling of the chassis.
At this time, we do not sell any alternative transformers for this amplifier.
I’m interested in this amp but am not finding many reviews of its sound qualities. Can you describe the soundstage, tonal qualities, and dynamics of the TU-8300R?
Hello! An in depth review is in the works and should be available soon.
Was this the same amp that was used at the Toronto Audio Visual Electronics Show ?
Yes this is that exact amplifier.
Most inspiring article, and leaves me only this question: Does the kit come in voltage for New Zealand? We have 240volts home supply here. Would that be a problem?