mosfets said:
That's fine, but the way you're going about it is impractical. If I follow what you currently say you want to build: you are going to use back-to-back 12V transformers to save money, but they will require a voltage doubler, which you want to implement with tubes. It's not easy to implement a voltage doubler with tubes, because the increased ripple is more difficult to filter, especially for a preamp. By the time you are finished you will have spent more than if you just spent a few extra dollars for a 120VAC:240VAC isolation transformer in the first place.
And as a personal aside, those who won't admit that sand does at least SOME things better are living in denial.
leadbelly said:
I may end up eating crow because I took a long hard look at the local option for metal and the Hammond 369AXP certainly looks good. My problem is, if I purchase and build the better electronic stuffing, then I generate a need to build a premium enclosure. Not that I should'nt but I was hoping to move quick to get a result that was ok. More whistles mean more delay.
To get real crafty on the situation, I think if I thrift shop the right piece of broken vintage test gear, I may be able to score an amazing power supply transformer. This would enable a better supply, on a frugal budget and the chasis could be the standard metal slab on a boring oak or mahogony box. Always too many options. I need mostly, to make some decisions and stick to them to see it through.
About the wiring on the power supply I posted. I want to know what others think about directly tying a DC heater to ground versus floating a connection from the common point of two resistors across the heater supply and then connecting to the H+ ground. Know what I mean
?
...and any other suggestions for such a circuit in post #37.
Cheers.
?...and any other suggestions for such a circuit in post #37.
Cheers.
Miles Prower said:
Miles
You are certainly right to mention the many factors which may have an effect. Still, my conclusions are not based on a single example and they show peak currents have very little to do with the issue. Even in a low current, low capacitance, multiple LC stage preamp supply SS diodes are glaringly obvious. And i find mosfets in the direct signal path or CCSs a lot less intrusive than diodes in PS. Some time ago i rebuilt one of my favourite amps into a civilised-looking chasis and was forced to use semis for rectifiers. Used Cree shotkys (probably not a wise choice) and initially thought the amp was not that bad. After several years it has seen less than 50 hrs of play - it's a completely uninvolving sound - and now i'm getting ready to salvage parts from it.
Attachments
It is part of the problem. The EI with 83 rectifiers was simply quite different. I compared the effects of the transformers and rectifiers separately and the rectifiers were by far more audible. The input stage has a separate PS and any changes there are in turn more audible than the same at the outputs. Many ways to wreck an amp without changing the basic specs.
TUBE RECTIFICATION
First of all, I find it hard to believe that people do not hear obvious differences like tube rectifier vs solid state rectifier.
There is no comparison, meaning that the two are so not in the same league that it should be evident from the first moment you listen.
I made my first experiences with PP amps (yes, I built those as well, if some tought I was just an SE guy they were mistaken: how else could I know what I prefer) and for that matter the difference was earth and sky. On preamps the difference is even more pronounced, and you can experiment with various tube rectifiers that fit the same socket since output current is not strictly important (i.e. 5R4, 5AR4, 5Y3, 5Z4... etc.). Each tube recitifer has a sound of its own in the same application, and you can use that to fine tune the sound of your preamp, or even amp... or even the whole system.
On the other hand, not the same with SS diodes. The difference in sound is much less pronounced, if any. Of course, Shottky differs from 1N4007... but that is like comparing an Opel Astra with a Ford Focus... and comparing them both with (at least) BMW X5 or X6... no comparison, frankly, although some would certainly prefer the cheapness of the SS diodes with no need to replace them after some xxxx hours of work.
Very interestingly, this thread has lost the preamps and gained the rectifiers
Is it because people are more into rectifiers than preamps?
First of all, I find it hard to believe that people do not hear obvious differences like tube rectifier vs solid state rectifier.
There is no comparison, meaning that the two are so not in the same league that it should be evident from the first moment you listen.
I made my first experiences with PP amps (yes, I built those as well, if some tought I was just an SE guy they were mistaken: how else could I know what I prefer) and for that matter the difference was earth and sky. On preamps the difference is even more pronounced, and you can experiment with various tube rectifiers that fit the same socket since output current is not strictly important (i.e. 5R4, 5AR4, 5Y3, 5Z4... etc.). Each tube recitifer has a sound of its own in the same application, and you can use that to fine tune the sound of your preamp, or even amp... or even the whole system.
On the other hand, not the same with SS diodes. The difference in sound is much less pronounced, if any. Of course, Shottky differs from 1N4007... but that is like comparing an Opel Astra with a Ford Focus... and comparing them both with (at least) BMW X5 or X6... no comparison, frankly, although some would certainly prefer the cheapness of the SS diodes with no need to replace them after some xxxx hours of work.
Very interestingly, this thread has lost the preamps and gained the rectifiers
Is it because people are more into rectifiers than preamps?SAND AND GLASS
OF COURSE THEY DO! WE WOULD NOT HAVE PCs IF THE SAND WAS NOT INVENTED!
And we would not have cheap sound allround if sand was not invented... old radios sound better than their SS counterparts, even "blond monsters" do. I actually grew up listening to a tube "radio grammophone" combination, and all my friends were always amazed how records sounded (better) at my place.
OF COURSE THEY DO! WE WOULD NOT HAVE PCs IF THE SAND WAS NOT INVENTED!
And we would not have cheap sound allround if sand was not invented... old radios sound better than their SS counterparts, even "blond monsters" do. I actually grew up listening to a tube "radio grammophone" combination, and all my friends were always amazed how records sounded (better) at my place.
Re: Re: TUBE RECTIFICATION
You can make this suggestion to Audio Research as well although in their case it might not help - their best effort for a regulator is coupled with a tube rectifier. I doubt anyone would seriously suggest that the tube rectification is a marketing ploy in their products. Their target customer simply doesn't care.
leadbelly said:
You can make this suggestion to Audio Research as well although in their case it might not help - their best effort for a regulator is coupled with a tube rectifier. I doubt anyone would seriously suggest that the tube rectification is a marketing ploy in their products. Their target customer simply doesn't care.
If by regulated power supply you mean "SS regulated power supply", NO, I have never done that. It would be silly to regulate with SS if you rectify with tube diodes.
I really do not know whether you could still hear the tube rectifiers presence thru SS regulation. Most probably you could not, because the "haze" of the SS stages would make it "unhearable". If you understand what I am trying to say.
On the other hand, if the regulation is with tubes, I can say that you should hear the difference. For various reasons, obviously. Tube regulation is less efficient in what SS does best, and generates less haze as well. Tube regulation is always interesting, but...
What I am assuming when we say tube rectifier, is a "simple" circuit with chokes and caps (and resistors if necessary or chokes are not available). If you cannot hear the difference in such a circuit, than it is obvious that something is terribly wrong with your system, or your hearing, for that matter. No pun intended, whatsoever... but people who are hearing challenged usually do not listen to much music or build amplifiers to listen to music.
I prefer tube rectifiers, and simple LC circuits. To me, they sound better than tube rectified and tube regulated circuits... and much, much, much better than SS rectified and SS regulated, and SS rectified and simple LC. In that order, approximately. Maybe a matter of taste, but certainly not to be confused with mixes that make no sense (tube rectification and SS regulation).
By the way, I do sometimes wonder how would SS amps with transistors or mosfets sound with tube rectifiers
I really do not know whether you could still hear the tube rectifiers presence thru SS regulation. Most probably you could not, because the "haze" of the SS stages would make it "unhearable". If you understand what I am trying to say.
On the other hand, if the regulation is with tubes, I can say that you should hear the difference. For various reasons, obviously. Tube regulation is less efficient in what SS does best, and generates less haze as well. Tube regulation is always interesting, but...
What I am assuming when we say tube rectifier, is a "simple" circuit with chokes and caps (and resistors if necessary or chokes are not available). If you cannot hear the difference in such a circuit, than it is obvious that something is terribly wrong with your system, or your hearing, for that matter. No pun intended, whatsoever... but people who are hearing challenged usually do not listen to much music or build amplifiers to listen to music.
I prefer tube rectifiers, and simple LC circuits. To me, they sound better than tube rectified and tube regulated circuits... and much, much, much better than SS rectified and SS regulated, and SS rectified and simple LC. In that order, approximately. Maybe a matter of taste, but certainly not to be confused with mixes that make no sense (tube rectification and SS regulation).
By the way, I do sometimes wonder how would SS amps with transistors or mosfets sound with tube rectifiers
I have Mullard 5AR4 rectifiers in my 300B SET amps and I wouldn't trade it for anything. I also have a 6X5 rectifier inm my preamp and it sounds great too. I would't want regulation.
Too many people talk about how good regulation is before they even try it. SS regulation may be good for smalll signal transistor circuits or DACs etc. Even then it has to be implemented properly.
Too many people talk about how good regulation is before they even try it. SS regulation may be good for smalll signal transistor circuits or DACs etc. Even then it has to be implemented properly.
I am not sure there is any point responding, since you continue with your wild generalizations. Two comments:
1) I never specified that the regulator be SS, so at least one of you has built a straw man.
2) Are you sure AR put a tube rectifier in there for fidelity and not to avoide cathode stripping?
1) I never specified that the regulator be SS, so at least one of you has built a straw man.
2) Are you sure AR put a tube rectifier in there for fidelity and not to avoide cathode stripping?
labjr said:
What do you mean, even then? It ALWAYS has to be implemented properly. And there are so many ways to get it wrong.
Surprisingly, it is so with a semiconductor rectifier - one would think, what's there to go wrong in a circuit that has a transformer, a couple od diodes and a filter cap - for one thing, it has a whole lot of 'invisible' parasitic components and too few of the real ones to take care of the parasitics!
It is quite possible to hide the ringing/reverse recovery/peak current saturation of rectification behind filters and regulators, but if you have multiple windings on your transformer, count on the rectification current waveform being coupled into other windings. If one of them is the heater winding... I'm sure you get the idea. Another common mistake, DC heaters, where the high current heater winding is rectified by SS into a huge reservoir cap - in this case the hash goes the other way, from the heater supply to the main B+.
In general, un-damped LC circuits (and there are plenty!) that are left ringing once the SS diode recovery stops or conduction starts (so at any ABRUPT current change) can create all sorts of problems, and this is far from only being a tube circuit thing. High bandwidth transformers with tightly coupled windings such as toroids make things a LOT worse. Use low ESR caps in this situation, and it is worse still. Add a mains filter in such a case it will get even worse than that - one case that comes to mind was an amp that had separate toroids for various supplies, but they were all using a common mains input filter.
The 'soft' caharcteristic of a tube rectifier and lack of recovery, as well as rectification down to millivolts, successfully lessen most of the above effects by default. So does adding rectifier tube-equivalent resistances in series with SS diodes, and designing with the same limitation on first stage filter caps as with tubes (although the latter requirement can be signifficantly relaxed with SS rectifiers).
Alex Kitic said:
Not necessarily. Before jumping to conclusions try something like Salas shunt or a shunt Superreg.
leadbelly said:
Quite sure. The luxury of tube rectification appears only in the Reference series which employ both tube and SS regulation, so delayed B+ is not an issue. The lesser models with SS rectification employ various methods of B+ delay like ramping regulators or relays.
Leadbelly, this is a quote of what you have written yourself, I believe?
You are right! I was unable to believe what I read, and assumed that the SS was for "regulator" instead of rectifier... and, to finish that one off, you are right. I would certainly need a better regulator, since I said myself that tube regulators are not that good as one might imagine in comparison to the results of the SS regulators.
BUT, they are good enough. AND, not for me, since I prefer NO REGULATION, i.e. the power supply must be "powerful" enough to withstand the power demands of the circuit with the minimum fluctuation of values, something which is quite easy to achieve with what I occupy myself, and that is SE amps (very little variation in power demand due to the intrinsic class A operation) and preamps (very little current needed, easy to provide a much more powerful supply than necessary -- and of course, the constant current draw circuit makes it even easier on the power supply).
That said, I hope there is no need for further debate on the issue.
Re: TUBE RECTIFICATION
I'm not discounting the possibility that there are those out there who hear things the rest of us can not. I can assure you that I, personally, can't tell any difference. Of course, I've done things a bit differently in that I put the Si diodes on their own HV xfmr so that I can power up the heaters before hitting 'em with the HV. May be that keeps SS artifacts out of the rest of the circuit?
What's obvious to you is a big mystery to me.
Alex Kitic said:
I'm not discounting the possibility that there are those out there who hear things the rest of us can not. I can assure you that I, personally, can't tell any difference. Of course, I've done things a bit differently in that I put the Si diodes on their own HV xfmr so that I can power up the heaters before hitting 'em with the HV. May be that keeps SS artifacts out of the rest of the circuit?
What's obvious to you is a big mystery to me.
Not at all!
Sorry to hear that. What tube rectifiers did you try so far, and in which circuit? Maybe that will help us all understand.
You know, some people seem to prefer SS diodes. I am comfortable with that, some like blonds and some brunettes... but not hearing any difference? There must be something wrong with that setup.
Interesting discussion . I was looking at the Audio Note Preamps and also Shindo (mostly reading description of those) and they seem to prefer tube rectified and tube regulated circuits .Audio Note switched to tube regulated PSU for their preamps from hefty double choke IP supplies (but still retained the choke) I wonder why they use such a big transformers ,chokes for such small current draws? I bet all transformers have an electrostatic shields between windings and copper shield strips outside to prevent EMI. Knowing English manufacturers they would save a half of a cent if they only could so all of this has it's merit
I think PSU details/magnetics are the reason kits are inferior to finished products.
I think PSU details/magnetics are the reason kits are inferior to finished products.