...Split ends???
If it can accept an infinite charge for an infinite amout of time (i.e. a capacitor of infinite capacitance) then it is certainly not a piece of wire! It would have to have zero impedance (or its temperture rises to infinty) and zero inductance too (ditto)
What it is I don't know... not even in theory other than something with infinite capacitance and no other property...
Pretty damm useless - so now the hairs must be fully split
ciao
James
p.s.
John.
I'll get your D3 email done this week - things have been frantic over the summer... easing up a bit now...
If it can accept an infinite charge for an infinite amout of time (i.e. a capacitor of infinite capacitance) then it is certainly not a piece of wire! It would have to have zero impedance (or its temperture rises to infinty) and zero inductance too (ditto)
What it is I don't know... not even in theory other than something with infinite capacitance and no other property...
Pretty damm useless - so now the hairs must be fully split
ciao
James
p.s.
John.
I'll get your D3 email done this week - things have been frantic over the summer... easing up a bit now...
> The turn on surges can be lessened by using tube rectifiers and ...they're so much easier on components, aren't they?
I am probably going to be evicted for this opinion.....
Tube rectifiers suck.
They waste a LOT of power. They give off a lot of heat. They use a lot of space. They complicate the wiring. They can't (easily) be used in some rectifier configurations. They ruin regulation.
And they do not reduce turn-on surge. The direct-heat rectifiers turn-on in 2 seconds, your heater-cathode tubes need 10 seconds to turn-on, so there is still a long period when B+ is very high. Much higher than if you used sand-state rectifiers and adjusted transformer voltage to give the same final loaded B+, because the tubes need 50-150 volts extra transformer to cover losses under load and there is no load until the heater-cathode tubes warm up.
Yes, sand-state rectifiers smack the capacitors awful hard. But caps have improved SO much since 1938 that it isn't an issue.
> So, now you know why grandma's radio lasted forever...
Grandma's radio did NOT "last forever". Radio repair was big business, and most radios needed repair every year or two. My father made money in high school that way. Yes, there are 1930s radios still working fine, but many-many-many more were scrapped over the years because they were too much trouble to keep-up.
And don't get me started on Tube TVs. On one hand, they were good for the industry because the high parts-count forced improvements in all parts. Parts got much better through the 1950s. On the other hand, at their best they crapped-out every year or two. There were tube-testers in every drugstore, that's how big a problem it was.
> no excuse why your tube amp shouldn't last forever...
Correct. With modern parts and worst-case design, DIY tube gear should last a VERY long time. Your labor is worth more than the few bucks extra needed to use over-rated parts (2W instead of 1W, 600V instead of 400V).
I am probably going to be evicted for this opinion.....
Tube rectifiers suck.
They waste a LOT of power. They give off a lot of heat. They use a lot of space. They complicate the wiring. They can't (easily) be used in some rectifier configurations. They ruin regulation.
And they do not reduce turn-on surge. The direct-heat rectifiers turn-on in 2 seconds, your heater-cathode tubes need 10 seconds to turn-on, so there is still a long period when B+ is very high. Much higher than if you used sand-state rectifiers and adjusted transformer voltage to give the same final loaded B+, because the tubes need 50-150 volts extra transformer to cover losses under load and there is no load until the heater-cathode tubes warm up.
Yes, sand-state rectifiers smack the capacitors awful hard. But caps have improved SO much since 1938 that it isn't an issue.
> So, now you know why grandma's radio lasted forever...
Grandma's radio did NOT "last forever". Radio repair was big business, and most radios needed repair every year or two. My father made money in high school that way. Yes, there are 1930s radios still working fine, but many-many-many more were scrapped over the years because they were too much trouble to keep-up.
And don't get me started on Tube TVs. On one hand, they were good for the industry because the high parts-count forced improvements in all parts. Parts got much better through the 1950s. On the other hand, at their best they crapped-out every year or two. There were tube-testers in every drugstore, that's how big a problem it was.
> no excuse why your tube amp shouldn't last forever...
Correct. With modern parts and worst-case design, DIY tube gear should last a VERY long time. Your labor is worth more than the few bucks extra needed to use over-rated parts (2W instead of 1W, 600V instead of 400V).
Hi,
Economically, yes. Sonically I don't think so.
They could if we pick the right ones and 2 to 10 secs. is still easier on the tubes and caps than full blast at switch-on from silicon diodes.
Only time will tell.
Not our experience in Europe, they only part that would almost certainly die was the filter cap unless it was a PIO....
Not common for radios I admit.
From experience, not just my own, most tubes tend to age extremely slow in radios.
They quite often test "as new" when pulled. Surprising but true.
Mind you I don't use any tube rectifier in my gear using Schottky diodes instead.
For as far as I'm concerned these to are getting better every year.
We just see the SiliconCarbide HT Schottkys hit the market now but for the current asking price you can pick up a lot of damper diodes that do come up slowly and are much more efficient than a regular tube rectifier.
Good to see we agree although this is definetely NOT the case of most high-end gear I came across...guess they to have to make a living doing repairs.
Repairs that are often SS related problems though, regs blowing, causing tubes to go south etc. Not pretty.
With a little careful design you can make most tube ams last a lifetime with nothing more than a set of output tubes to relace every two to three years.
Cheers,
Economically, yes. Sonically I don't think so.
They could if we pick the right ones and 2 to 10 secs. is still easier on the tubes and caps than full blast at switch-on from silicon diodes.
Only time will tell.
Not our experience in Europe, they only part that would almost certainly die was the filter cap unless it was a PIO....
Not common for radios I admit.
From experience, not just my own, most tubes tend to age extremely slow in radios.
They quite often test "as new" when pulled. Surprising but true.
Mind you I don't use any tube rectifier in my gear using Schottky diodes instead.
For as far as I'm concerned these to are getting better every year.
We just see the SiliconCarbide HT Schottkys hit the market now but for the current asking price you can pick up a lot of damper diodes that do come up slowly and are much more efficient than a regular tube rectifier.
Good to see we agree although this is definetely NOT the case of most high-end gear I came across...guess they to have to make a living doing repairs.
Repairs that are often SS related problems though, regs blowing, causing tubes to go south etc. Not pretty.
With a little careful design you can make most tube ams last a lifetime with nothing more than a set of output tubes to relace every two to three years.
Cheers,
fdegrove said:
My experience with paper caps is they always, ALWAYS go south and leaky in old radios. I doubt one large enough to filter a half wave would ever be used, it would be absolutely enormous and also cost several x $10 (and I mean in those days' money)!
I'm with PRR on this, they were very cost-driven in those days, and accordingly, repair was big business.
Tim
TOO YOUNG TO DIE TOO OLD TO ROCK'N ROLL
Hi,
Papercaps, yes...PIO caps are not the same.
I'm with PRR on this, they were very cost-driven in those days, and accordingly, repair was big business.
Not so in Europe where you'll find marvellous pieces of engineering just prior to WW2 and for 10 to 15 years after that.
Note that I don't want to start WW3 here, just note in your little book of history that in those days quality came first.
Cheers,
Hi,
Papercaps, yes...PIO caps are not the same.
I'm with PRR on this, they were very cost-driven in those days, and accordingly, repair was big business.
Not so in Europe where you'll find marvellous pieces of engineering just prior to WW2 and for 10 to 15 years after that.
Note that I don't want to start WW3 here, just note in your little book of history that in those days quality came first.
Cheers,
>They waste a LOT of power.
Not THAT much. Anyway, who cares?
>They give off a lot of heat.
How much more than silicone diodes? Again, insignificant issue.
>They use a lot of space.
??!! 2.5" X 2.5" max.
>They complicate the wiring.
You're really reaching here. That issue isn't going to stop anyone on this forum
>They can't (easily) be used in some rectifier configurations.
True, bridges with DHR's need two extra filament windings, but this isn't a normal implementation.
>They ruin regulation.
Well, you do have a point there, but with class A, an ordinary "brute force"-regulated power supply works well enough.
If you had written, "Tube rectifiers SUCK; they sound TERRIBLE.", I wouldn't argue with you. But, nearly everyone agrees that they sound better, so a pragmatic diatribe isn't going to wash in most DIY audio enthusiest circles. I don't wish to be flippant, but one reason I moved over to this forum from rec.audio.tubes is that it (RAT) had become dominated by types who weren't interested the sonic qualities of more esoteric designs, components and tube types. I mean, is there really an ultimate class AB push-pull EL34 amp out there worth pursuing?
John
Not THAT much. Anyway, who cares?
>They give off a lot of heat.
How much more than silicone diodes? Again, insignificant issue.
>They use a lot of space.
??!! 2.5" X 2.5" max.
>They complicate the wiring.
You're really reaching here. That issue isn't going to stop anyone on this forum
>They can't (easily) be used in some rectifier configurations.
True, bridges with DHR's need two extra filament windings, but this isn't a normal implementation.
>They ruin regulation.
Well, you do have a point there, but with class A, an ordinary "brute force"-regulated power supply works well enough.
If you had written, "Tube rectifiers SUCK; they sound TERRIBLE.", I wouldn't argue with you. But, nearly everyone agrees that they sound better, so a pragmatic diatribe isn't going to wash in most DIY audio enthusiest circles. I don't wish to be flippant, but one reason I moved over to this forum from rec.audio.tubes is that it (RAT) had become dominated by types who weren't interested the sonic qualities of more esoteric designs, components and tube types. I mean, is there really an ultimate class AB push-pull EL34 amp out there worth pursuing?
John
jlsem said:
30W is a heck of a lot more than "who cares".
30W for maybe 250mA vs. what, uhm lemme see here LESS THAN A WATT?
2"x2"x6"
Tubes are often easier because they are their own terminal strips, rather than taking up a good 3 or 4 slots on a strip. But that's just a matter of a design consideration.
And what if you're shooting for a little more power than a class A amp can do? Hmm?
Though he usually uses 6550s or so - they're plentiful - EL34s can be used just as well in many of Patrick Turner's designs. Tell me those aren't "ultimate"?
Tim
>30W is a heck of a lot more than "who cares".
30W if you're using a pair of 81's maybe, but a GZ34 or better yet TV damper diodes waste considerably less than 30W. Besides, you missed the point: Tube amps waste a lot of power, so what's 10 or 15 more watts more gonna hurt, especially if you are looking for sonic advantages?
>Tubes are often easier because they are their own terminal strips, rather than taking up a good 3 or 4 slots on a strip. But that's just a matter of a design consideration.
That whole excuse for not using tube rectifiers was silly.
>And what if you're shooting for a little more power than a class A amp can do? Hmm?
A regulated power supply for a push-pull AB1 or AB2 power amp is really polishing a turd.
>Though he usually uses 6550s or so - they're plentiful - EL34s can be used just as well in many of Patrick Turner's designs. Tell me those aren't "ultimate"?
Never heard one. Patrick has come a long way since he began posting on RAT, and I mean no disrespect for the man, but designing amps from an RDH4 is nothing new, and admittingly he has come to dominate the forum and it now has limited interest for me.
John
30W if you're using a pair of 81's maybe, but a GZ34 or better yet TV damper diodes waste considerably less than 30W. Besides, you missed the point: Tube amps waste a lot of power, so what's 10 or 15 more watts more gonna hurt, especially if you are looking for sonic advantages?
>Tubes are often easier because they are their own terminal strips, rather than taking up a good 3 or 4 slots on a strip. But that's just a matter of a design consideration.
That whole excuse for not using tube rectifiers was silly.
>And what if you're shooting for a little more power than a class A amp can do? Hmm?
A regulated power supply for a push-pull AB1 or AB2 power amp is really polishing a turd.
>Though he usually uses 6550s or so - they're plentiful - EL34s can be used just as well in many of Patrick Turner's designs. Tell me those aren't "ultimate"?
Never heard one. Patrick has come a long way since he began posting on RAT, and I mean no disrespect for the man, but designing amps from an RDH4 is nothing new, and admittingly he has come to dominate the forum and it now has limited interest for me.
John
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