New 2A3 SET / Simple, but gentle sounding amplifier

[levelfive]

Hi, Friends

I produced today my new amplifier named Level Five.
After half year of preparing material I finally got around to publish my experience about designing and building an tube amp.

In the winter of 2008 I decided to build Single–Ended Stereo Tube Amplifier, using the 2A3 tube. There are many good solutions in the DIY community, but nothing seemed satisfactory to me. After looking at different circuits in the Internet, I have decided to calculate my own circuit design (see attach). Actually, that was my second DIY tube project.

The amp uses two 6SL7s in the preamp/driver, two 2A3s for the outputs and a 5U4G rectifier. It puts out right around 2.5W in pure Class A. To get more information about internal construction, grounding, component parts etc. please visit Level Five Amp page.

Newbies can follow the schematic diagram and build their own tube amp, circuit is very simple and don't need anything tune. It really helps to understand what’s happening in the construction you create. The sound depends on the passive components used only.

Best Regards, Konstantin

[Rassmussen]

Hello, congratulations on your design!
I'm a newbie in tube and will build my first .
I have found many schematic but yours level five looks great!
Is it really simple to build?

[levelfive]

Originally Posted by Rassmussen

Hello, congratulations on your design!
I'm a newbie in tube and will build my first .
I have found many schematic but yours level five looks great!
Is it really simple to build?

You are welcome!

Yes, it`s a very simple schematic with minimum components, but first be sure you really want to build your own amp from scratch. Honestly, my first tube project was the STA-35 kit. The kit will allow you to understanding how it works and the concepts of circuit design.
Level Five Amp is really simple construction, but for a first try it is more expensive than cheapest push-pull tube kit.

[Rassmussen]

Yes. I need a cheapest tube kit and your schematic I will keep for the next time.
Thank You, Konstantin, again.

[zerowaf]

Hi, Konstantin!
Congratulation for design and thank you for sharing your amp with us! I'm not expert (in anny way!), but I like to see chokes and tube rectifikation.
Right now I'm contemplating about making DM BL Horn with fostex 126, and I think I could use a little bit more power then 2.5 watt. Anyway, I will follow your site in future!

[Wavebourn]

Hi Konstantin;

what is the purpose of R6?

Also, I often see in designs from Russia usage of nylon cable ties to mount heavy capacitors in high temperature areas. I would definitely recommend to use something more reliable.

Good luck!

[levelfive]

zerowaf, Thank You too!

Originally Posted by zerowaf

Right now I'm contemplating about making DM BL Horn with fostex 126, and I think I could use a little bit more power then 2.5 watt. Anyway, I will follow your site in future!

FE126E model? With 94 dB Sensitivity?
I listen my Level Five Amp with Klipsch RF-15 speakers. Their sensitivity is 96dB,
This is more than enough!

[meshplate]

Konstantin, that's a nice looking amp with a good layout. I'm interested to know about the anodised faceplate. Is that something you cut/drill and then have brushed and anodised, or something ready finished that you carefully work afterwards. I wanted to use a black finish, but could not decide what would give a durable finish. The black anodised aluminium look really nice. Well done.

Steve

[levelfive]

Originally Posted by meshplate

I'm interested to know about the anodised faceplate. Is that something you cut/drill and then have brushed and anodised, or something ready finished that you carefully work afterwards.
Steve

Hi, Steve!
I bought a ready-made anodised faceplate. And then drilled carefully, of course, it is not convenient. If it possible - better to do it in reverse order.

Few details about chassis:
This is 19 inch standard rack with 10mm aluminium flanks, with painted black steel covers and additional oxidized black aluminium faceplate. The top cover was drilled in advance on my drawings.

And thank you for feedback!

[SemperFi]

Originally Posted by Wavebourn

Hi Konstantin;

what is the purpose of R6?

Also, I often see in designs from Russia usage of nylon cable ties to mount heavy capacitors in high temperature areas. I would definitely recommend to use something more reliable.

Good luck!

My bet is R6 is there to increase the plate load a tad, and perhaps to fine tune the plate voltage of the bottom triode? Though increasing R5 a bit and removing R6 does the same. ???

Nylon straps are an industry standard, quick and easy, and shouldn't be a problem. Granted, high heat makes them brittle, so in 20years or so they may turn brownish and even snap if someone forces them.