The return of the Jedi
Time has come when breadboarding and HT is not longer an option. With a baby around, I was forced to remove most of the valve equipment. However, the return of the Jedi is closer than you expect. With very little time, albeit at continuous pace when I get a free 30min here or there every weekend, I keep very focused on my objective. The 814 SE monster amp is close to retirement (probably before Christmas) and although I have a fantastic LME amp already working, I need to get the valves back on the scene providing I can prove I’ve complied with “heath and safety” – as my wife well put it.
Well, I had a nice attempt of a wooden frame made out of pine wood. Yes, I’m really bad at woodworking but I’m getting better. The top plates are 4mm thick. I have added a nice set of 2 100mA meters at the front of the frame. A 300VA custom-wounded multi-tap HT transformer from JMS which gives me full flexibility from 100 to 500V in 25V steps. The supply is choke input (LL1638) and filtered with a set of nice 50uF oil caps and 20H chokes. Damper valves used with some nice SiC to form a hybrid rectifier.
Top plates are protected with paper before drilling!
This looks to be quite neat in my view!
The idea is to use this supply for my new 4P1L PSE, 300B and DHT Schade experiments with 6P21S/47 and 1624 valves. A lot planned and so little time for this unfortunately.
Cheers, Ale
Hi Ale
I was interested to note your custom transformer from JMS. Is it their standard 300VA offering but just with custom specification on the secondary? I see they state a barrier between primary and secondary, is this actually an electrostatic screen? Is it mechanically silent at rated load? Their delivery lead times seem good, was that your experience?
Paul
Hi Paul
All my transformers are from JMS. I’ve used them for the last 5-6 years and am absolutely happy with their performance. The price is a bargain consider the small additional cost they charge for customising them. I always add a screen between windings, with exception of the filament transformers for DHT which are split bobbins, and also an outer screen. Multi-tapping of secondaries is great. My current 300VA transformer has 0-25-100-300-400-500 taps which provides all the flexibility needed to accommodate voltage requirements.
I can only recommend them, the quality of their products is great
Ale