Thanks Will and Colin, I'll have a punt around. I've only once used a valve rectifier, using a Mercury rect will be another thingy to play with over winter.
Is an 80 or 83 more desirable to run a pair of 2A3's and a pair of drivers? They don't seem to go for silly money, are folk scared of them?
Nick wrote:Normally 15v or so, but its a constant 15v irrespective of current, so they provide for a low impedance supply.
Ta for info Nick and Andrew, is a low Z PSU desirable in amplifiers? Any series 'R' to avoided if poss?
Ta for info Nick and Andrew, is a low Z PSU desirable in amplifiers? Any series 'R' to avoided if poss?
No simple answer to that, but generally as long as the supply is low enough ripple, and the low impedance doesn't create a bloody great hump in the frequency response of the supply in the middle of the audio frequency range, then yes, IMHO, I think a low Z supply is a good thing.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
it seems to me, in my simple way that an 80 is rather like a direct heated GZ32 and an 83 is rather like a direct heated GZ37, though 5U4 is closer in spec.
I'd monoblock with either and use one in each, or I'd use two for a complete 2A3 stereo integrated, not so much that you need the extra power; that is arguable. If you have the extra 5 volt winding, use it!
Ah, just found a data sheet for these 80 and 83 valves, they're a bit limited current wise aren't they compared to GZ34. 250mA max per 83 http://www.nj7p.org/Tube4.php?tube=83 even less for the 80.
I'd have to check on the spec of that recently acquired Hammond mains TX to see what it could power rectifier wise, I know there's one 5V tapping for a valve rectifier. Is it OK to power to rec's off one 5V winding (as long as it can supply enough filament current) to feed each channel?
um 83 on my integrated 300b amp was fine with one 83. Hammond 300b mains trafo, pair of 5693s, pair of 300bs. 80 is a tad lean I suppose but surely enough for a monoblock2A3?
andrew Ivimey wrote:
But diyhifisupply was selling valve arts 274s for £8 each so I bought 4. Huge classic bottle shape and I am using one in my SEXamp, just for looks.
thats what makes this place and it members 'special'....!
Blimey, all these new (to me) rectifiers coming out the woodwork. I dunno where to start, whats a 274 do that a GZ34 doesn't? S'not Merc Rec is it, it looks like a standard FW rectifier.
Nick wrote:I think a 274 is a higher resistance rectifier, so lower charging spikes.
Do I read 'higher resistance' as higher Z too Nick? The GZ34 is pref here?
DTB
Yes, but you need to play with "Power Supply Designer" to see how the resistance of the supply alters how it responds to step changes. You can see from that its not as simple as some seem to suggest.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
Steve WE274a are worth more than WE300b and go for £600-700
I've been selling a few valves and listed a couple on Ebay US W/Electric
the prices came as shock, I had a singleWE262b input valve untested I thought £30 it went to Honkers for £177.00.
thats what makes this place and it members 'special'....!
