Sorry to come into this VERY late, and with something that is not unknown to boot - but to sum up:
Over the years I have mostly found that in correct designs of power supplies - meaning that nothing is overly over or under-sized - power transformer, rectifier and equipment to be driven - one ends up without much concern for ruining something.
If an adequate but not over-the-top power transformer is used, it will mostly have enough series impedance to cope with larger filter capacitors. One must remember that the impedance at mains frequency (not dc resistance) is the governing factor limiting the peak capacitor charging current, also that the total impedance includes both secondary and primary, though under load (thus damped). With an oscilloscope and small series resistor the peak current can easily be checked and compared to tube data. My experience was that hardly ever did I need an extra series resistor with the right transformer, rectifier, etc.
Then also, is there an earth-shattering reason for not using silicon diodes these days? Tube rectifiers were not used because of some snake-oil aura of being better; there simply were no semiconductor rectifiers then (except for a short span of seleniums - yuch!) For puritans, they are not in the signal path despite some pseudo-scientific utterances to the contrary; there is the point of a peak voltage before the amplifier heaters warm up, but then so is it with 5U4s. I am as much of a tube veteran as the next man, but I am also a practical man. A recent (very) high-end tube amplifier of mine contains its share of semiconductor regulators, safety circuits etc. (but not in the signal circuit proper). I have learnt to expect initial furrowed foreheads (what!!!), but after explanations folks had to admit that there was no way the performance could have been achieved only tube-wise.
To each his pleasure, but just thought that I would air this.
Regards
Over the years I have mostly found that in correct designs of power supplies - meaning that nothing is overly over or under-sized - power transformer, rectifier and equipment to be driven - one ends up without much concern for ruining something.
If an adequate but not over-the-top power transformer is used, it will mostly have enough series impedance to cope with larger filter capacitors. One must remember that the impedance at mains frequency (not dc resistance) is the governing factor limiting the peak capacitor charging current, also that the total impedance includes both secondary and primary, though under load (thus damped). With an oscilloscope and small series resistor the peak current can easily be checked and compared to tube data. My experience was that hardly ever did I need an extra series resistor with the right transformer, rectifier, etc.
Then also, is there an earth-shattering reason for not using silicon diodes these days? Tube rectifiers were not used because of some snake-oil aura of being better; there simply were no semiconductor rectifiers then (except for a short span of seleniums - yuch!) For puritans, they are not in the signal path despite some pseudo-scientific utterances to the contrary; there is the point of a peak voltage before the amplifier heaters warm up, but then so is it with 5U4s. I am as much of a tube veteran as the next man, but I am also a practical man. A recent (very) high-end tube amplifier of mine contains its share of semiconductor regulators, safety circuits etc. (but not in the signal circuit proper). I have learnt to expect initial furrowed foreheads (what!!!), but after explanations folks had to admit that there was no way the performance could have been achieved only tube-wise.
To each his pleasure, but just thought that I would air this.
Regards
Johan Potgieter said:
The best reason I have yet heard for using tube rectifiers.
But one appreciates the slow turn-on motivation.
Regards.
really depending of goals and construction,sometimes tube rect is better ,sometimes is not
but, fun factor is always increased with another silly bottle
Ach no SY man! You Moderators are spoil sports!
Somewhat off-thread, but let me try to rehabilitate myself at least to a degree:
In a semiconductor amp I make and sell, I "had" to also install a tone control defeat button - OK, it is the customer's money. At a certain demo, quite a number of times folks claimed to hear the difference between controls at zero, bypassed and not. Point was, the switch was not wired in .....
Now back to 6X4s.
Regards.
Somewhat off-thread, but let me try to rehabilitate myself at least to a degree:
In a semiconductor amp I make and sell, I "had" to also install a tone control defeat button - OK, it is the customer's money. At a certain demo, quite a number of times folks claimed to hear the difference between controls at zero, bypassed and not. Point was, the switch was not wired in .....
Now back to 6X4s.
Regards.
To be fair, I did the opposite, too- brought a stock-looking Dynaco PAS-2 (rusty, of course) to an Audio Research/Mark Levinson dealer. Inside, of course, was the circuit I was selling in those days, active regulation, passive RIAA, zero feedback, noise-optimized, blah, blah. The look on the salesman's face when we hooked it up and compared it to his expensive units was not a pretty one. The downside was that I couldn't convince them to sell my mods no matter how good they were... (to keep this slightly on topic, one part of the mod was getting rid of the 12X4 and adding a cathode follower where the rectifier used to be)
This was 25 years ago. I'm older now and get my kicks in different ways.
This was 25 years ago. I'm older now and get my kicks in different ways.
Hi SY,
I get my kicks with those guys (stereo salepeople) at every opportunity. It's part of their education.
Selling mods in a store will never be successful until you are already successful in your own right. Still, you are far better off on your own - direct. It is a no flyer for so many reasons. Ever see the mark up a store wants on a straight repair? They make far more than the service shop, never mind the tech. That's one reason they use hackers.
Hi Johan,
You guys realise that simply installing a tube in a solid state amp will boost it's sales. Witness Luxman LV-105 and the Carver C-19 (I think).
-Chris
I get my kicks with those guys (stereo salepeople) at every opportunity. It's part of their education.
Selling mods in a store will never be successful until you are already successful in your own right. Still, you are far better off on your own - direct. It is a no flyer for so many reasons. Ever see the mark up a store wants on a straight repair? They make far more than the service shop, never mind the tech. That's one reason they use hackers.
Hi Johan,
Not at all surprising. Now what does that tell you?
You guys realise that simply installing a tube in a solid state amp will boost it's sales. Witness Luxman LV-105 and the Carver C-19 (I think).
-Chris
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