Re: Re: 30 Hz > 15KHz , 8 W rms , only £ 2477 for 2 .. Valve of course

[Bill Borland]

>> >> Don't skimp on quality, go for the best! > >>>> In Russ's quest to extract even more > >money from his customers' wallets > >performance from his Hi-Fi system, he's >> identified a new way of cleaning your mains supply that's even more >> effective than our Ultra Purifier mains filters. >> >> The new product 'balances' the mains and cleans the mains supply in a >> completely new way; it's quite capable of lifting the performance of your >> system to a completely new level. > >The principle is sound, like balanced audio circuits, it uses a >transformer with two secondaries of half the primary voltage, >connected in series, with the junction earthed and the load supplied >across the two outer ends. You could get a suitable transformer made >for much less than Russ charges. >

Do you simply mean a transformer with a centre-tapped secondary, or is there more to it than that?

[Brian Gaff]

I hate to think, you don't expect the guy to tell everyone his voodoo secrets? I suppose you also use a valve to do the rectification. I suggest the 5y3 myself, though you need a specially cleaned supply for the heaters to avoid heater/cathode intermediation distortion....

grin.

Brian

[Brian Gaff]

My spell checker invented the type of distortion, but actually its quite apt considering all that heated discussion this has caused... Brian

[TonyL]

+1 here on that. Those nasty silicon rectifiers with their harsh, fast nanosecond switching will place severe stresses on your precious audio equipment during start up, not to mention generating troublesome radiation of noise from those ugly sharp switching transients. Using a 5Y3 will solve these problems by applying HT gradually as/when your valves are ready for it and, since it is a valve, your HT noise will sound much nicer...warmer and more soothing.

:-)

[David Looser]

"TonyL" wrote

Whilst the 5Y3 will be expensive, short-lived, inefficient and can cause a lot of damage to other components when it fails. Of course silicon rectifiers don't actually cause "severe stresses on your precious audio equipment" if the system has been designed with even a modicum of care. Nor, for that matter, will they cause "troublesome radiation" either in a reasonably competent design.

If stress on components is your main concern may I recommend the choke-input filter? It also provides a far better load regulation than the common capacitor-input configuration.

David.

[Jim Lesurf]

If you wish it is also trivially easy to do things like

a) Put small RF caps across diodes to suppress any brief snap

b) build a PSU that ramps up the voltage slowly when first turned on

without needing to use valves for the rectifiers.

Slainte,

Jim

[TonyL]

Stress in myself is my main concern, rather than in any audio circuit...or rather minimising it. One method is the use of humour, oodles of it...which my original post contained.

[TonyL]

Absolutely, my suggestion was tongue in cheek but some didn't seem to get that. I recently completed a 12V 50A supply using transformer/rectifier technology because I couldn't find a switched mode PSU that was sufficiently noise free (Part of the kit it supplies is a sensitive HF receiver).

I used both a) and b).

Item b) was trivially easy using a ramp-up series resistor that is bypassed by relay contacts when the (pre-regulated) output voltage is greater than

80% of its design level.

[Jim Lesurf]

I have tended to use the approach shown in the PSU in the last diagram on

view at

the zener defines the nominal output level (minus the device drops) and the following RC gives a smooth rise. I also like the design being able to easily define the output impedance to the rail when you don't need 'as near zero as possible'. Just choose values for designed purpose.

Although I've tended to do that only when noise is the main concern, so mainly for things like preamps or signal conditioning or even microwave device PSUs.

For power amps I have tended to just design them to be unflustered by the switch on surge. Easy enough with solid state devices. Although I have played a bit with valves in the past it hasn't been for audio purposes.

Slainte,

Jim

[David Looser]

"TonyL" wrote

I'm not sure that anybody 'got it'.

The trouble is that there are a lot of people out there who would say what you said and mean every word. I don'tr see how we are supposed to tell the difference between them and someone who is saying it tongue in cheek. In Usenet we are deprived of the clues of facial expresion and tone of voice which would give the game away face-to-face.

David.

[TonyL]

OK, timing circuit noted, thanks.

A bit more elaborate than my approach which simply relies on the threshold voltage of the zener for switching and the rampup resistor value for timing.

[TonyL]

The clue was the smiley, plus my mention of the resulting HT noise being "warmer and more soothing"...which was a bit of a jibe about those who like the "warm tube sound"

:-)

[David Looser]

"TonyL" wrote

The poor smiley has to convey any of a wide range of meanings, which is meant in any one post can often be obscure.

plus my mention of the resulting HT noise being

Or, alternatively, a comment by someone who likes the "warm tube sound" :-).

As a rule I think it best not to attempt "tongue-in-cheek" in Usenet, it hardly ever works.

David.

[TonyL]

Whatever...

Suggestion...chill out....relax...enjoy...smile. We come this way only once, so enjoy the ride :-)

[Jules]

You might. I'm planning on coming back as a pigeon so I can crap on politicians.

[TonyL]

He he,

One of the old-timers, I see. I just missed the G3 series and settled for: G4AUD or more correctly now: GW4AUD

73's

Tony

of Shareware Professionals developer member