jh6you
The explanation is around page 3/post 30.
Peter Daniel
You are a full fledged designer now so it shouldn't be too hard to get Plitron to fork over one of their smaller parts like a single "LoNo" 160VA to test on the whole amp. It may not improve your sound without changing some other stuff because your amp is so optimized around the larger 225VA parts with the diodes you selected, topology and the mounting used, etc. but I'll wager that the single smaller transformer will smooth the sound and make it more liquid with a bigger soundstage but it might cost you some dynamics. As you know from your experience, you can tweak up the hardness and dynamics by changing the materials so I think it would be worth a try.
The explanation is around page 3/post 30.
Peter Daniel
You are a full fledged designer now so it shouldn't be too hard to get Plitron to fork over one of their smaller parts like a single "LoNo" 160VA to test on the whole amp. It may not improve your sound without changing some other stuff because your amp is so optimized around the larger 225VA parts with the diodes you selected, topology and the mounting used, etc. but I'll wager that the single smaller transformer will smooth the sound and make it more liquid with a bigger soundstage but it might cost you some dynamics. As you know from your experience, you can tweak up the hardness and dynamics by changing the materials so I think it would be worth a try.
Hi,
Confused you are indeed...
What you should take abstract of is the primary side and secundary side of the powerxformer.
At the primary side you can have any primary voltage for the grid supplies, i.e. 240VAC for Europe and say 115 VAC for the US.
Since the power comes from the grid it basically equals the raw AC voltage supplied.
You will find xformers with multiple primary voltages that, when combined in a certain way, parallel, series or a combination of both will adapt the primary to whatever is available from the powergrid.
At the secondary side we can have several windings, each having a specific VA rating.
For example; 1* 24VAC at 1A will give us a 24VAC secundary and a 24VA powerxformer.
Another winding at, say 12VAC 0.5A will be 6VA and when added to the one above will give a 30VA xformer and so on.
Hope this helps,
Confused you are indeed...
What you should take abstract of is the primary side and secundary side of the powerxformer.
At the primary side you can have any primary voltage for the grid supplies, i.e. 240VAC for Europe and say 115 VAC for the US.
Since the power comes from the grid it basically equals the raw AC voltage supplied.
You will find xformers with multiple primary voltages that, when combined in a certain way, parallel, series or a combination of both will adapt the primary to whatever is available from the powergrid.
At the secondary side we can have several windings, each having a specific VA rating.
For example; 1* 24VAC at 1A will give us a 24VAC secundary and a 24VA powerxformer.
Another winding at, say 12VAC 0.5A will be 6VA and when added to the one above will give a 30VA xformer and so on.
Hope this helps,
"One such change examined was the size of the amplifier's power transformer. A clear correlation emerged between improved dynamics and rhythm and increased transformer VI rating. One explanation is that the larger transformer provides superior regulation, hence more stable internal power rails. Even more important, a larger transformer helps the reservoirs recover their equilibrium more quickly after a transient. Consequently, the amplifier spends more of its time in equilibrium. "
its takin' from this article by martin collums...
http://www.stereophile.com/fullarchives.cgi?23
....so please stop this b...s..., bigger is better - allways.
have any of you guys ever heard of anyone recommending a lesser trafo to get better sound - well i haven't for sure....!!!!
its takin' from this article by martin collums...
http://www.stereophile.com/fullarchives.cgi?23
....so please stop this b...s..., bigger is better - allways.
have any of you guys ever heard of anyone recommending a lesser trafo to get better sound - well i haven't for sure....!!!!
It's difficult to conduct 'clean' experiments with transformers but for what it's worth i once tried increasing the size from around 150VA to over 1kVA with very negative results. Dynamics in particular suffered a lot. I don't claim the VA rating was responsible, as clearly the two transformers (EI types) were very different.
Interestingly, yldouright mentions higher diode noise for very low resistance secondary; it never occured to me but it may be a factor.
good reading
I just caught up on this thread and it inspired me to do some experimenting on my new gainclone (first amp, btw!) I have a honkin 750 VA plitron w/25v secondaries. I have naim speakers, and while I have no idea what the impedence curve looks like (rated 6 ohms), the only amp I've ever heard make them really sing is the aleph. the gainclone gives great bass and its extremely detailed and clean, but there's no musicality, and they get really thin in the midrange(as every other amp makes them sound). I need to fill out the midrange somehow. I was thinking of buying a lower voltage transformer (this one is on loan from my aleph in progress anyway) but maybe I can just wire the primaries in series in the morning and see what that does. As it is though, my clone makes my midget missions sound absolutely amazing on vocals (lyle lovett "songs from the movies" is awesome!). never thought they would sound that good since they came with one of those mini denon reciever units.
Still have to rewire the left channel eventually cuz its all buggered... anyhow I think 750 VA should be enough even if VA rating is cut in half, although the 12.5 rms will be a bit low. I get around 20w for 6 ohm speakers from the graph posted earlier. do the transformers get hotter when I wire the primaries in series? I don't want to do any permanent damage. btw bass slam is amazing on these things. I can't believe how low and clean it goes, and that with cheap surplus caps of unknown type it did take about 10 hours to start to open up though. anyhow I'll post my results.
I just caught up on this thread and it inspired me to do some experimenting on my new gainclone (first amp, btw!) I have a honkin 750 VA plitron w/25v secondaries. I have naim speakers, and while I have no idea what the impedence curve looks like (rated 6 ohms), the only amp I've ever heard make them really sing is the aleph. the gainclone gives great bass and its extremely detailed and clean, but there's no musicality, and they get really thin in the midrange(as every other amp makes them sound). I need to fill out the midrange somehow. I was thinking of buying a lower voltage transformer (this one is on loan from my aleph in progress anyway) but maybe I can just wire the primaries in series in the morning and see what that does. As it is though, my clone makes my midget missions sound absolutely amazing on vocals (lyle lovett "songs from the movies" is awesome!). never thought they would sound that good since they came with one of those mini denon reciever units.
Still have to rewire the left channel eventually cuz its all buggered... anyhow I think 750 VA should be enough even if VA rating is cut in half, although the 12.5 rms will be a bit low. I get around 20w for 6 ohm speakers from the graph posted earlier. do the transformers get hotter when I wire the primaries in series? I don't want to do any permanent damage. btw bass slam is amazing on these things. I can't believe how low and clean it goes, and that with cheap surplus caps of unknown type
it did take about 10 hours to start to open up though. anyhow I'll post my results.
ok, lets do it the hard way...find a sponsor, and get a full line of exactly the same trafoes - say 25-0-25 volts - 50va, 80 va, 120va, 160 va, 225va, 300va, 500va, 800va and 1000va.
...and believe me, the sound improves all the way up.
of course there is a point, when you stop hearing any improvements verses $$$ spent......but its not getting worse...!
"Turning to transformers: I remember an amplifier designer of my acquaintance pondering whether there was a limit to the improvement to be gained by substituting beefier and beefier power supplies for one of his preamplifiers. He built a number of power supplies, each using a larger transformer than the last. With each increase in size, careful listening revealed that the sound was that slight bit better. Ultimately he built a power supply with the same transformer as his largest power amplifier. Sure enough, the sound was better still. "
its takin' from this article....(its very good reading btw)
http://www.stereophile.com/showarchives.cgi?54
...and believe me, the sound improves all the way up.
of course there is a point, when you stop hearing any improvements verses $$$ spent......but its not getting worse...!
"Turning to transformers: I remember an amplifier designer of my acquaintance pondering whether there was a limit to the improvement to be gained by substituting beefier and beefier power supplies for one of his preamplifiers. He built a number of power supplies, each using a larger transformer than the last. With each increase in size, careful listening revealed that the sound was that slight bit better. Ultimately he built a power supply with the same transformer as his largest power amplifier. Sure enough, the sound was better still. "
its takin' from this article....(its very good reading btw)
http://www.stereophile.com/showarchives.cgi?54
analog_sa said:
yes, this is why Phred and a few others have advocated using small-value damping resistors between the secondary and rectifiers, when power loss is not a significant factor. i'm not sure if they would be advantageous in a gainclone design, probably not, but for a preamp or digital circuit they are worth trying.
I also understand that choosing right transformer is not an easy affair. I once tried 2 big (250VA) EI transformers with 18V secondaries ea., one transformer per rail. In comparison to a single Plitron toroid (400VA), the PS with 2 EI trafos didn't sound as good (kind of flat and not involving) which was a surprise to me.
Those 2 EI were also bigger than Plitron toroid
Those 2 EI were also bigger than Plitron toroid
fdegrove said:
At the secondary side we can have several windings, each having a specific VA rating.
For example; 1* 24VAC at 1A will give us a 24VAC secundary and a 24VA powerxformer.
Another winding at, say 12VAC 0.5A will be 6VA and when added to the one above will give a 30VA xformer and so on.
Hope this helps,
As you say, How can I connect 3 wing each 6.5V to a 19.5V transformer? 3 wires each wing, how to do so? Also how can I measure the Current? mA/AC-DC A/uA setting? Is it using AC setting to measure secondary wings?
http://headwize2.powerpill.org/ubb/showpage5.php?fnum=3&tid=4219&fdays=20&fpage=2
P.S: The copper cover one.
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