I remember a short project/article in an old ETI magazine (perhaps 1986?), the premise was to recreate a valve sound using transistors (5x MPSA42?). From memory the preamp had a two small transformers back-to-back and a rectifier to create an HV rail and a gyrator config using at least one transistor for the PSU. It was at least two stages and had an RIAA network slung between them, feedback was provided by emitter resistors?
I think the ETI copy had something white on the front (like a synth). Could also be wrong on the year (85-87).
Don't suppose anyone remembers the article or has a stash of old ETI's?
I think the ETI copy had something white on the front (like a synth). Could also be wrong on the year (85-87).
Don't suppose anyone remembers the article or has a stash of old ETI's?
It is just easier to use a tube. 12ax7 and 6922 and others work great for signal levels below 10v with 70v B+. They may work somewhat better at high B+ but likely not audible.
70 to 150v is easy to get with reverse transformer. You just need heater power.
70 to 150v is easy to get with reverse transformer. You just need heater power.
The whole point of the article is the experiment with using transistors in a valve/tube configuration.
Which does seem doomed as e^x (BJT characteristic) is not x^1.5 (approx valve characteristic)... It would be more logical to try FETs with their approx x^2 characteristic.
Warning it gets nostalgic rereading old ETI's from that era!
Warning it gets nostalgic rereading old ETI's from that era!