In my amp the rectifier was some cheapo bridge with 4 x snubber 0.01 caps.
Replaced the bridge with schottky C3D04065E diodes - very pleased with change!
Replaced the bridge with schottky C3D04065E diodes - very pleased with change!
SS diodes yield superior power supply regulation. That's generally a good thing, especially in class AB triode power amplifiers, but there are folks who enjoy the sonic effects of power tube bias shifting with music tempo.
Silicon diodes don't switch as cleanly as vacuum diodes. The resulting reverse current spikes can excite ultrasonic power transformer resonances and radiate RF noise. Morgan Jones showed that transformer resonance is easy to eliminate with snubbing networks. RF noise susceptibility varies, but it's typically less of a problem in tube amps relative to SS amps. Bursts of RF energy are rectified in susceptible stages and converted to an audible 120 Hz buzz, so you will know if you have this problem.
I listed some reasons in my previous post, but if you make your own amps with parts purchased from here and there, using a tube rectifier is the best way to achieve the the B+ you need in the circuit specs. If you need to drop say 50vdc a 5R4 rectifier will do that. If you want to gain 40 volts of that back switching to a 5ar4 will bring up the B+. Of course, i am generalizing here and the numbers are dependent upon the voltages. And if you want to use SS rectifiers you can easily accommodate that by getting one of those empty octal sockets and solder in the diodes of your choice and convert your amp to SS. You can't beat that for versatility.
I am not adverse to SS as i have been using transistors for CCS and LEDs for this and that.
Why do people new to this site often start silly polls, asking questions which others have been discussing for years? Are we now supposed to design audio amps via democracy?
You could find an amp that uses a tube rectifier and A-B the rectifier with one of these;
https://www.tubedepot.com/products/solid-state-rectifier. This is the opinion of a an amateur so add salt. But in my humble opinion tube rectifiers sound better. The whole point of vacuum tubes is that ANALOG sweetness that sounds more alive, more like real instruments and voices.
Yes, some tube rectifiers turn on more slowly, the ones that are indirectly heated like GZ34 which also drop much less voltage. But 5U4G which is directly heated cathode turn on much faster. (A point that I learned when Eli recently pointed it out to me.)
But with SS you can use a standby switch for the filaments. With filaments hot tubes will conduct immediately so the inrush current is split between the capacitors and the tubes softening the start and extending the life of the caps. The first cap limitation isn't really important in my opinion because there is plenty of filtration beyond the choke. And a small first cap at high voltage is less expensive and physically smaller.
You say in your first post that you don't want a contest over which sounds better. Which is subjective. But it is also the only real consideration in my opinion because done correctly they can both be made to sound very good.
Your ears are analog, they don't "switch." Neither do piano strings, clarinets or human voices. Reproducing analog sound in digital formats is less expensive and more convenient. But if you are willing to use SS rectification why not just use transistors instead of tubes?
https://www.tubedepot.com/products/solid-state-rectifier. This is the opinion of a an amateur so add salt. But in my humble opinion tube rectifiers sound better. The whole point of vacuum tubes is that ANALOG sweetness that sounds more alive, more like real instruments and voices.
Yes, some tube rectifiers turn on more slowly, the ones that are indirectly heated like GZ34 which also drop much less voltage. But 5U4G which is directly heated cathode turn on much faster. (A point that I learned when Eli recently pointed it out to me.)
But with SS you can use a standby switch for the filaments. With filaments hot tubes will conduct immediately so the inrush current is split between the capacitors and the tubes softening the start and extending the life of the caps. The first cap limitation isn't really important in my opinion because there is plenty of filtration beyond the choke. And a small first cap at high voltage is less expensive and physically smaller.
You say in your first post that you don't want a contest over which sounds better. Which is subjective. But it is also the only real consideration in my opinion because done correctly they can both be made to sound very good.
Your ears are analog, they don't "switch." Neither do piano strings, clarinets or human voices. Reproducing analog sound in digital formats is less expensive and more convenient. But if you are willing to use SS rectification why not just use transistors instead of tubes?
DF96, in real life I'm a master auto technician. And once or twice a year my boss hires a green kid. And that kid comes to me asking the same questions and posing the same arguments that they all have for the last forty years. Its part of the learning process. One thing I have learned on this site is to search out threads that apply to your questions before you start a new thread. Or better yet do some research (i.e. Morgan Jones) Saves looking like an idiot which I do often enough on my own.
You're assuming that this is being asked in good faith. Me, I'm just eating my popcorn and watching with amusement.
yes, from forward conductio n to reverse bias condition depending or which part of the ac cycle is present at the plates...
soft means a lot of good things. When you scope your B+ you can see the nice sinusoidal ripple... no jagged edges, etc.. and this can bring real benefit, such as observing mains transformer or your input choke is not vibrating, etc. too. Of course snubbers and more expensive silicon diodes exist that are better than 1N4007. but then you're spending more money anyway - right? And oh yes.. they glow too. Kind of funky twisted heaters inside..
They're all pretty much good. 6AU4 and 6AX4 (and their various related cousins) are the usual ones to go for. 6AU4's need a bit more current.. Note they are diodes - so you need two to make a full-wave rectifier with them. And they need 6V for the heaters (not 5V). They come up real...nice...and... slow.............. 😉
Check the specs sheet on the 6AU4. Peak inverse volts for 6AU4 is a mere 4'500V. Can the 5U4 do that? I think not... And the prices should be still not too crazy. I bought a lifetime supply of these a few years ago and have barely made a dent. I like the coin-bottom variety from the late 60's / early 70's. Nobody else seems to want them. 😀
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All of the arguments you can make about rectifier tubes being crappy (they need heater power, they've got lots of voltage drop, they're not as efficient, blah blah blah) can be equally applied to every other tube in a tube amp.
But I don't see anyone here arguing that transistor amps are better.
*shrug*
But I don't see anyone here arguing that transistor amps are better.
*shrug*
i use tube rectifiers for the simple reason that i have them on hand, got them for a song or bought them for a dollar each....
if i do not have them, i will not go out of my way to get them...
this is a Sakura amplifier with tube rectifiers supplying +-6 volts to an rc4558 op amp...with just two resistors,
i was able to get them inoperative and the amp still works....now the tubes are there for display...
if i do not have them, i will not go out of my way to get them...
this is a Sakura amplifier with tube rectifiers supplying +-6 volts to an rc4558 op amp...with just two resistors,
i was able to get them inoperative and the amp still works....now the tubes are there for display...
For high powered class AB amps I stick with SS for low impedance and larger capacitance capabilities.
For low power class A amps I use tubes rectifiers because I have boxes of them and....well.....why the hell not.
For low power class A amps I use tubes rectifiers because I have boxes of them and....well.....why the hell not.
Ah... wait. silicon diodes are very useful devices. Transistors too. They just need to be used in places that make use of their best qualities.
I often use two 1N007 diodes to create a virtual center tap (graetz bridge) with damper diodes. they are perfect for this duty.
MOSFET's are transistors that are superb for current regulation duty. They can also be used in follower circuits. Many posts exist on this in this forum.
So yes, solid state devices are very important!
Good question actually - though I'm not sure if you're being sarcastic or not. Assuming you're not, operationally they're the electronic equivalent of a check valve, so are ss diodes - cracking pressure and all.
Hi, I like using fully regulated power supplies in my hi-fi tube amps, but I still use indirectly heated rectifiers or damper diodes when I can for the slow HV rise-up. It's a simple yet effective way to achieve this. And with SS regulation, the High value filter caps aren't such a concern.
If you using rectifier tubes in high voltage RF circuits such as 1000 watt AM ham transmitter or even the modulator,rect tubes are quite useful because they can take abuse.
In an audio amp,they are lossy but for some scenarios that may be a good thing if you need a voltage drop of say 40v..The advantage to an indirect heated rect like a GZ34,gives you a slow ramp up of the B+ while your output devices are warming up and that way they aren't hit with instant high voltage.
Bottom line,with the good solid rectifiers that we have today such as Schottkys and other low noise types which are super quiet,you can use much more filtering off them without fear of damage.I'm not saying you need it but it's there if you want it.
As far as sound goes between tube and SS rect,I don't rect tubes have any sound to them.With the different voltage and current one puts out vs the other is going to have more effect on the sound than the rect itself. If you have a 350vdc supply that is well regulated and well filtered regardless of whether it is a tube or rect diodes,as long as the voltage was consistent,I don't think you would hear much difference. JMHO YMMV
I'm really glad you asked this. One less stupid question for me! 😀
+SoulMerchant Thank you for expounding on "slow". I didn't realize things like 6AX4 existed as a separate entity from axial or tab type diodes that Google showed.
I don't yet understand how they're different, but knowing what something is called puts you one step closer to search results 😀
Electronics is the one field I've put off studying for lack of time and the fact that it's sort of a mountain, with MANY foothills.
I did read a lot of threads, and you can believe I'll be searching something from almost every post in this thread.
Thank you for helping.
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