seavote said:
winston i was planning on using the Gyraf G9 PSU and adjusting the B+ V. a few DIY members have done this and love their redd preamp clones. are there better topologies for the PSU? the G9 is regulated.
http://www.gyraf.dk/gy_pd/g9/g9_sch.gif
is the PSU you spoke about in a recent thread. more similar or different than the G9 PSU?
That supply is a decent basic supply it should work in the circuit.
I do things differently when I have the budget. Some might say more than is necessary, to which I reply: "At the end of the day, you're listening to the power supply". As a matter of fact, I sometimes DO listen to power supplies by blocking the DC and shoving it into a power amp. Of course, there's also scopes to see what's happening.
There are several small (in themselves) things that I do that, when added up, make fairly decent improvements I.M.O.
There's hi-freq noise on your ac, there's hi-freq. hash from your diodes. TL783's don't help as much at higher frequencies for eliminating this stuff. Generally, 3 terminal, adjustable regs are about the worst sonically in my opinion. If you have to use them, build the ouput out a few ohms or more to isolate a bit and add a good shunt cap. The output impedance isn't as low then but it's still WAY lower than a standard CRCRC filter bank and you
will notice it if you do a few other tricks as well. By itself, on a bog-standard supply...? Maybe.
Torroidal transformers are another thing: they may radiate less field but they're also wider bandwidth and let in more garbage from the mains.
It's all about attention to lots of details that, when added up, might get you that extra 5%.
I mean no disrespect to the Gyraf supply. It's as good as any that are generally used in Pro gear. I've used worse myself when budget was a consideration. It also has a proven track record in many units that people are more than happy with
Depends how far you want to take it really or, more realistically, how much time you want to spend learning, adapting and applying the tricks. The learning and applying never really ends, not in my case anyway. If it does (it won't, I'm not that smart), I'll go do something else.
My $0.02
John