) You are evil-ish. No the question is simple. I might get lost in translation here and there but I think that there are a couple of people out there who tried all the topologies and have at least a vague opinion about what is better than what.
My goal is to build the most transparent SET amp i can.
Topology is vital. You will rather tell the diffrence between 2 topologies that between 2 MKP caps.
For me Best=most transparent.
I suggest using transparent acrylic or museum quality glass for the chassis. Clearly this will result in the most transparent amp. You may want to hide the transformers in a separate sub-chassis as they'll impede the flow of photons through the chassis, thereby, reducing transparency.
Your question makes as much sense as trying to decide which flavor of ice cream to buy by asking everybody, "what's your favorite flavor". Mine is chocolate, by the way. Or coffee... Mmm..... Coffee.
~Tom
Your question makes as much sense as trying to decide which flavor of ice cream to buy by asking everybody, "what's your favorite flavor". Mine is chocolate, by the way. Or coffee... Mmm..... Coffee.
~Tom
I see that there is a "i know it all" syndrome around here.
What is stupind in asking what is better: an interstage transformer, or a coupling cap?
Where is the none-sense?
About interstage transformers:
"This means that you can do something very different, and that is run the interstage with no load on the secondary. You have a driver valve, the interstage, and then the output valve, nothing else apart from your bias components and of course the power supply. This means that the driver valve is running essentially into an AC infinite impedance (well very, very high anyway) at audio frequencies, which in modern parlance translates as constant current operation; the loadline is horizontal. To a driver triode, that means lower distortion, and maximum voltage swing, swing that can exceed the HT supply rail. This cannot happen with one of the funky, complex stacked systems often seen as clever constant current loads; things like SRPP or the mu follower."
Audio Note Kits - Interstage Coupled Amps
Enjoy your coffee Tom. I'll drink mine in 8 hours.
What is stupind in asking what is better: an interstage transformer, or a coupling cap?
Where is the none-sense?
About interstage transformers:
"This means that you can do something very different, and that is run the interstage with no load on the secondary. You have a driver valve, the interstage, and then the output valve, nothing else apart from your bias components and of course the power supply. This means that the driver valve is running essentially into an AC infinite impedance (well very, very high anyway) at audio frequencies, which in modern parlance translates as constant current operation; the loadline is horizontal. To a driver triode, that means lower distortion, and maximum voltage swing, swing that can exceed the HT supply rail. This cannot happen with one of the funky, complex stacked systems often seen as clever constant current loads; things like SRPP or the mu follower."
Audio Note Kits - Interstage Coupled Amps
Enjoy your coffee Tom. I'll drink mine in 8 hours.
Hmmm....
I am with rvrazvan on this one. There are many threads regarding the "best" capacitor, resistor, transformer, tubes and so on. The only difference is that these are single components. Non-the-less, opinions are given freely, like chocolate vs coffee.
I don't think the OP is asking for a definitive single answer, rather a collection of opinions, hopefully with some rationals, so he may cogitate on them and come to his own conclusion. It is not a stupid question or request, just a difficult one.
BTW, I am jealous. Lactose intolerance makes it only possible for me to enjoy my coffee hot. I miss coffee ice cream....
I am with rvrazvan on this one. There are many threads regarding the "best" capacitor, resistor, transformer, tubes and so on. The only difference is that these are single components. Non-the-less, opinions are given freely, like chocolate vs coffee.
I don't think the OP is asking for a definitive single answer, rather a collection of opinions, hopefully with some rationals, so he may cogitate on them and come to his own conclusion. It is not a stupid question or request, just a difficult one.
BTW, I am jealous. Lactose intolerance makes it only possible for me to enjoy my coffee hot. I miss coffee ice cream....
You are asking for best design, but offer already pre-supposed means to get "best parts" for the certain design that is not necessary the best. Like, presence of coupling caps and interstage transformer, for example. Pentode/triode. All parts when present and used can fit in best (I mean optimal) design, but they may be absent in another best design. According to my own preferences, the design have to be optimal all together, including selection of parts and topology. Like a tight knot that is optimal and functional when completed, all together, nothing to add/nothing to remove. If to change anything, it will be just another knot. May be no less as functional. Like, fancy-coiled bulk rope may be used instead of a knot, but I doubt it would be optimal, and I would not call it "the best".
I don't think this is the place to ask questions the way you do....
Why don't you read (and learn) on the subject first?
My guess, at least I hope so, is that the majority of forum members make their orientations before coming up with questions, suggestions and so on.
This is important to keep the quality of this forum at a reasonable level.
With your questions you induce a senseless discussion IMHO.
Why don't you read (and learn) on the subject first?
My guess, at least I hope so, is that the majority of forum members make their orientations before coming up with questions, suggestions and so on.
This is important to keep the quality of this forum at a reasonable level.
With your questions you induce a senseless discussion IMHO.
No the question is simple. I might get lost in translation here and there but I think that there are a couple of people out there who tried all the topologies and have at least a vague opinion about what is better than what.
My goal is to build the most transparent SET amp i can.
Topology is vital. You will rather tell the diffrence between 2 topologies that between 2 MKP caps.
For me Best=most transparent.
I agree with many here, about your question being very problematic.
Here's some questions for you:
How transparent, for which speakers and at what wattage? How big a room do you have, what sort of music to you listen to and at what average SPL level? How much money are you willing to spend to get "the best"? Are you prepared (and can afford) to replace tubes often?
Which SET amplifier topographies have you listened to already and what short-comings did you find with them?
These are very important questions, so think about it carefully before answering.
Best Regards,
TerryO
OK, I am still under the strong impression that the question cannot have any definite answer ... but the topology I prefer and I used is
two stages directly coupled (with stacked supplies if necessary) parafeed output stage, here it comes a headphone amp I built last winter (now replaced with something simpler)
two stages directly coupled (with stacked supplies if necessary) parafeed output stage, here it comes a headphone amp I built last winter (now replaced with something simpler)
An externally hosted image should be here but it was not working when we last tested it.
I don't think your question is stupid, but I do believe it's a question that is impossible to answer.
You start out by asking for the best SET design. The answer to that question will depend on who you ask. It's not possible to arrive at a definite answer that works for everybody. Just like my example with the ice cream.
You follow up with questions like "is A better than B?" but without putting any qualifiers on it. What do you mean by better? A 10-cent ceramic cap always performs better than a $100 inter-stage transformer when competing on price alone. OK, so you probably weren't asking about the best price performer, but rather the best sound quality (another thing that's very hard to quantify). The capacitor allows for one set of engineering tradeoffs; the inter-stage transformer for a different set. Which one is better? My answer to that question would be, "yes".
If you are designing an amplifier, I would encourage you to ask questions along the lines of "I'm building an amp with the following tubes and am considering using an inter-stage transformer instead of a coupling cap. What are the tradeoffs of the two?". This would invite a dialog rather than give you a list of 'bests'.
You can see my latest design here: http://www.diyaudio.com/forums/tube...300b-idea-request-comments-3.html#post2440807
Note that I'm using an input transformer, hence will skip the coupling cap on the input. To me, this design will always be the best. At least until I come up with something else that's better...
~Tom
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Well... right now i'm buildind a 6c33 SET. The original ideea was to use Borbely's design published in Glass Audio. It was recomanded to me by the same who made my transformers(opt's).
I was concerned in the first place when i saw that it has two stages, one being SRPP.
Since i'm new to this field i always find new information that i do not digest right away. It takes some time to do that.
I don't think it will be to hard or to expensive for me to have some interstage transformer custom made.
I don't care to much about tube lifetime. I do care about the sound and i don't want any parts that can spoil the music. That's all. I want the most basic setup that gives the best results. And i have no ideea about how the final schematic will look like.
Diferent people, diferent opinions. Post them.
I was concerned in the first place when i saw that it has two stages, one being SRPP.
Since i'm new to this field i always find new information that i do not digest right away. It takes some time to do that.
I don't think it will be to hard or to expensive for me to have some interstage transformer custom made.
I don't care to much about tube lifetime. I do care about the sound and i don't want any parts that can spoil the music. That's all. I want the most basic setup that gives the best results. And i have no ideea about how the final schematic will look like.
Diferent people, diferent opinions. Post them.
OK, here's my 2 cents, and I will relate it to what I'm doing. I am playing with Pete Millett's red board. The board will accomodate many different types of sweep tubes. Over the past few months, I have collected many different types of these tubes and test each push pull pair. I then note which ones I liked and which ones I didn't. I listen to many different types of music, so I make sure I try each type. After many months, I have chosen my push-pulls.
So what I am saying is, everyone you ask will give you a different answer. If you can afford to build each type, listen to the music YOU like and then make a judgement. Sure it may cost you a bit of money, but I think on the long run it will be a design that YOU like.
Like I said, just my 2 cents....
Ray
So what I am saying is, everyone you ask will give you a different answer. If you can afford to build each type, listen to the music YOU like and then make a judgement. Sure it may cost you a bit of money, but I think on the long run it will be a design that YOU like.
Like I said, just my 2 cents....
Ray
Boberly is an excellent designer. If you think that's what you want, then just build it.
I would have recommended "Bottlehead SEX" for you as a beginner, but evidently you had already made up your mind.
Best Regards,
TerryO
I would recommend to look at Michael Koster's Meteor design. It is similar to SRPP, but uses MOSFET-based gyrator on top, directly coupled to the output tube. Such an approach makes concerns about input Miller capacitance, also about non-linear direct grid current, obsolete. No dynamic distortions caused by the grid driven through coupling capacitor can happen, so it is much better than bulk and expensive interstage transformer that adds own dirt.
why faff about with transformers or caps - they are all a compromise on DC coupling. Reduces your inductive coloration to just the opt, and no caps in the signal path.
Better still, dump the opt as well and go OTL. Now you only have the inductive colouration of the speakers.
Advantage - an all-glass, no iron amp so transperancy assured.
Better still, dump the opt as well and go OTL. Now you only have the inductive colouration of the speakers.
Advantage - an all-glass, no iron amp so transperancy assured.
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