First tubes in 30 years


I had tube preamps (CJ PV4, ARC SP6B, ARC SP9) in the 80's. They usually sounded great, but I had enough problems with them (tube failures, microphonics, background hiss) that eventually I switched to all solid state.  

Over the last couple years, I've really gotten into DIY and decided it would be fun to try a tube project. I've been intrigued by the idea of a 300B SET amp, so I built a set of monoblocks. I started with the basic design (and transformers) from the ANK 300B Parallel SET C-Core Monoblocks, and added a lot of upgrades. Check out my virtual system for details.

jaytor's virtual system page

I have to say, I'm really enjoying the sound. They are still in the early stages of breakin, with new WE 300Bs installed a week ago, but they are making a lot of music sound better than with any of my other amps (mostly Pass XA60.8s recently).

I'm planning to build a tube preamp as one of my next projects.

128x128jaytor

Thanks for the kind words.

Now I have to decide whether to sell my XA60.8s. These are great amps, and are a nice "reference" to have to compare my DIY projects. But they are pretty big and heavy, so a little hard to tuck in a corner, and I have way too many amps at this point (is it possible to have too many amps 😁?).

You used honest to goodness Western Electric 300Bs...  From their website, a matched pair is $1,500 dollars, and you have monos so times two...  Well, good stuff doesn't come inexpensively.  As for selling your Pass XA60.8s, don't do that; those are some very fine amplifiers.  If you're using a Pass preamp, I bet that sounds pretty astounding.  In my experience, Pass amps are "picky" when it comes to that "just right" sound.  I went through a few preamps before I picked up a Pass and boy oh boy, I wish I had done that sooner.  Nice job on your SETs.  

@noromance - I'm using a Jensen input transformer for the balanced inputs. The driver stage is coupled to the 300Bs using a c-core interstage transformer. Then another c-core transformer for the outputs. 

The 300Bs each have a Tentlabs filament supply (voltage controlled current source). The driver tube (6SH7) has a Pete Millet regulated heater supply. I'm also using a Neurochrome 21st century Maida regulator. 

@lucky_doggg7 - yeah the WE tubes don't come cheap. But right out of the box, they were very clearly superior to the Linlai tubes I started with (mostly because I didn't want to risk damaging an extensive tube when I was first checking out the amps). 

I'm using a DIY preamp which I'm pretty happy with. This is my second DIY preamp build. You can see details on my virtual system page. 

At this point, it's unlikely I'll buy another commercial product. I am really enjoying the whole process of building my own. So far, I have primarily been using subassemblies designed by others, but I'm starting to experiment with my own ground-up designs as well.