Glasshouse 300BSE (clone??) build.

[Riggers]

Hi All
It has been a few months since I completed this build but wanted to give it a good test run before I published anything on the forum. (just in case I built a death trap or burnt the house down )

I have always been very impressed with my WD88 VA but wanted to dip my toes into the waters of a single ended design. And...the challenge to build an amp from scratch with just a circuit diagram and bom.

It might come as a surprise but I have run the amp successfully driving my WD25T's. You will hear plenty of people say that to experience low power valve amps at their best you need 90+ db efficient speakers but I would go along with Herb Reichart's observation that an easy to drive impedance over the frequency range is more important. I am not playing them to ear-bleeding levels but they can go plenty loud enough and sound great.

Why the Glasshouse design? There are a few SET 300B designs on the internet, I guess it came to having faith in the designer, Andy Grove, and knowing that at least a few of these had been built and used successfully (including Richard from the WD forum).

These days the design is expensive to execute, not least of all the lm323 voltage regulators. I made the choice to go all in with Hashimoto opTx's and decent but not over the top caps. I figured this could well be the last power amp I build as I now have 2 amps of different design approach but that perform well and that I am very proud of.

I have attached a few picks to show my work.

I must thank this forum (and Matthew Snell) for giving me the opportunity to buy my original WD88 amp and the support necessary to get it performing well. I must also thank John Caswell for his patience and generosity for taking multiple phone calls with my list of questions.

I'm interested to hear what you think.

Phil.