Very nice PCB Marc, now even improved.
Did you finished you current DIY amp yet, Quasi isn't it?
Very nice PCB Marc, now even improved.
Did you finished you current DIY amp yet, Quasi isn't it?
I made some progress on quasi project : the front panel is varnished, yet i have to apply epoxy resine on MDF boby. I do that in parallel with my listening room (little home theater too) in my basement. I begin from zero and needed to built wall, electric distrinbution, thermic insulation as floor humidity insulation by applaying a specifique 2K epoxy resin.....
This evening i order new pcb board to etch new TSSA pcb version and soft start/speaker protection board as the 1µ/100v wima that left me. So yet ia can go foward with TSSA project.
Marc
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For me Jazz is the most revealing, true "acid test", since PRAT (Pace Rhythm And Timing) is everything at Jazz. Live Jazz performances daily in summer time offers major experiences, sound absorptions, tasting and learning how live instruments and Jazz band should sound. System must be capable to reproduce near live experience and that happens only when PRAT is OK. Musicians come together playing the same tune, they're tuned together, if not, complex Jazz takes sounds like tune's falling apart, musicians not playing in the same composition. To me Y axis correlations (phase, time, frequency) are the most important ones, amplitude related distortions are much more tolerable.
YES!
Nice !
I'm sure you will notice a sound and measurement differences. As the currents are huge on the output lines, you can see a real voltage differences between the point right out from a power transistor and the common output point, despite it is the same track..
Taking the Feedback right from the output point where speakers are feed makes-you sure that your feedback represent exactly the signal you need to treat. I experienced that in 1970, and on the amp we were working on at this time, measurement showed a /10 factor in distortion. Now, it is a reflex.
Hi, L.C.
It is not phase differences, but short level differences, due to PSU voltages decreases during transients. And you know that our ears localize both on phase and level differences.
As your two trasfos are the same, you can test in rely the two + and - lines of the 2 amps with a BIG diameter wire, and see if any listening difference ?
Worse is the PSSR of the amps, more you will notice a more stable image with a single PSU. I know you understand
As you said, nothing mysterious.The result will be that instruments will take less width in the stereo image with more empty space between them.
Of course, you will notice that more obviously with records mixed from studio recordings and multitracks mixing (Rock'n roll and some Jazz album) using level based stereo (stereo position set with a "Panpot"), than with some classical records, based on phase stereo, recorded with couples of microphones (levels are quite the same on the two tracks).
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Very nice PCB Marc, now even improved.
Did you finished you current DIY amp yet, Quasi isn't it?
Re Hi LC, I recieve today the lefting parts for TSSA project following (some wima, fuse clips, and new Pc board to etch improved TSSA version. The only thing i missing is the TLP627, but project can go on for first steps without It.
So i think i will etch new borad next week, and than wait foryour instruction to go on with electronic building....
Marc
WOW nice, show us new PCB-s and than will start.
Try to locate SFH619A
I can source TLP627 but it is in a another supplier where i made latest order. I juste see if i not need another souround part. I think i be able to show you new pcb next weekend.
Marc
I'm not sure how many from here are following the thread TSSA V1.6 docs and buyers list so I thought I would post some listening impressions here of the design that Sonny has developed.
The Set up:
25V + 25V rails from choke regulated supplies
o/p bias current 1A
CLG 23
Caddock TF020 in FB & gain positions
Playing music for about 1 week
Small mod done to "snubberise" the rail by pass caps
With the above conditions in place this amp has come to me as quite a revelation, I have never heard such clarity before and it is musical also and gives real insight into the music.
I'm not saying that it does not have character - there is quite high HD and this can sometimes be noticed but it is not really unpleasant, more like a little added richness to the sound.
I am not new to amps with CFB so I guess the remarkable clarity has to be due to:
The symmetrical topology
The fact that the VAS is the o/p stage.
I have heard it said that true transparency can never be realised in global FB amps with follower o/p stages and also JLH said that symmetrical amps tend to sound more detailed ( don't think he meant it as a complement )
I suspect that the main cause for this extraordinary clarity is having the VAS as the o/p stage but if there is someone here who has heard both SSA & TSSA I would love to hear your comments about how they compare.
My thanks to Sonny for offerring this great amp and to Andrej for the idea.
more details on other thread
mike
The Set up:
25V + 25V rails from choke regulated supplies
o/p bias current 1A
CLG 23
Caddock TF020 in FB & gain positions
Playing music for about 1 week
Small mod done to "snubberise" the rail by pass caps
With the above conditions in place this amp has come to me as quite a revelation, I have never heard such clarity before and it is musical also and gives real insight into the music.
I'm not saying that it does not have character - there is quite high HD and this can sometimes be noticed but it is not really unpleasant, more like a little added richness to the sound.
I am not new to amps with CFB so I guess the remarkable clarity has to be due to:
The symmetrical topology
The fact that the VAS is the o/p stage.
I have heard it said that true transparency can never be realised in global FB amps with follower o/p stages and also JLH said that symmetrical amps tend to sound more detailed ( don't think he meant it as a complement )
I suspect that the main cause for this extraordinary clarity is having the VAS as the o/p stage but if there is someone here who has heard both SSA & TSSA I would love to hear your comments about how they compare.
My thanks to Sonny for offerring this great amp and to Andrej for the idea.
more details on other thread
mike
Seems like you're not that familiar with "the sound of topologies" and relationship between sound and simulation.
It will be hard to understand from reading words (especially comparing different designs). It must be experienced. Build the LC's BIGBT-HP. It has the most impressive simulated performance, and has some correlation with its sound. The output stage has its own character (can be used with different input stage) and the driving stage has that low distortion character that you can use with BJT output stage (usually not enough "drive" for driving laterals).
Also try to remove the input ccs of your amp and listen...
I think the critical difference between TSSA and SSA is the damping factor. But use of high trans-conductance device and paralleling device will change that very characteristic.
Simpler circuits tend to sound magical. I think it is similar reason (simplicity) why tube amps sound magical. Magical could also mean "sweeter than reality", so not always positive.
EDIT: I think Esperado has mentioned many things about relating "theory" to "real world". Imo, he is the best one to explain such things.
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Actually it is very easy to adjust OLG of sonny's TSSA so perhaps I will try that.
But I do intend to built my own TSSA stage by stage from simplest to most complex going from low gain / DF to quite high gain / DF so I'll find out what sounds like what.
My main question right now is this: Is the incredible transparency of TSSA maintained when a follower O/P stage is added to create SSA ?
I know that damping factor is not the full story because my Fetzilla & TSSA's have similar DF but the sound is very different.
But I do intend to built my own TSSA stage by stage from simplest to most complex going from low gain / DF to quite high gain / DF so I'll find out what sounds like what.
My main question right now is this: Is the incredible transparency of TSSA maintained when a follower O/P stage is added to create SSA ?
I know that damping factor is not the full story because my Fetzilla & TSSA's have similar DF but the sound is very different.
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ahhh.... Jay show us you work or .... ..
Words and sim is fine.. But real world build, test, listening is what counts!!!!!!
I have build like 15 different designs over my 20 years experience in audio.
I have build several amps. both VFB, CFB. Some measure very well ... But does not sound good at all.
You cannot generalise if you have not build them all your self and found where the differenses is.
It can be in the detail...
And most of the sims done in this forum, is hard to realize in real world.....
Words and sim is fine.. But real world build, test, listening is what counts!!!!!!
I have build like 15 different designs over my 20 years experience in audio.
I have build several amps. both VFB, CFB. Some measure very well ... But does not sound good at all.
You cannot generalise if you have not build them all your self and found where the differenses is.
It can be in the detail...
And most of the sims done in this forum, is hard to realize in real world.....
The number will drastically drop once you start to design your own amps. Many hours are normally spent for a single amp. Building other people design is only a few one or two hours, until you run out of trusted designs.
I think high DF through gain setting (OLG or CLG??) is critical only with mosfet output, especially laterals. I don't know with Sonny's TSSA, but it seems to me that 1K/100 is a bit too small. 2K2/100 looks normal visually.
Honestly I'm not sure which one is SSA and which one is TSSA, as I don't use input cascode. I assume TSSA has caps in the FB (AC coupled).
I don't think that SSA can be made as transparent as TSSA unless we use cascaded VAS. With TSSA, add ccs, add regulated supply, add CURRENT! (Class-A) and it will become more and more transparent.
Fetzilla cannot be made as transparent as TSSA. I found it is difficult to work with, or bias the JFET. And the asymmetry of Fetzilla will normally cause a very pronounced 2nd order that will reduce transparency.
Check the noise floor. I believe Sonny's TSSA stands out. Transparency can be seen from this performance.
Mike's opinion from TSSA 1.6 thread:
Yes, very insightful music reproduction, now also because of your PSU. It would be nice at the end of your TSSA journey to show us final power supply schematic.
Very good job Mike.
Final comment before close of play . . .
Before I did the mod this amp sounded quite extraordinary but I noticed I relaxed more when I switched back to my DC linked fetzilla. Fetzilla gave less insight but was more refined & relaxed.
After the mod, and using my simple choke supplies, this TSSA 1.6 is the best amp I have ever heard by quite a bit margin. Now extremely insightful and quite refined.
I think there is still room for some more small refinements but already quite outstanding.
I now intend to do design a regulated supply - which I think this design will benefit from - and generally explore the whole field of 2 stage amps to the fullest extent possible.
Thanks Sonny - quite a masterpiece . . . You have opened up a new audio universe for me and I hope you enjoy the little suggestion I offer
Yes, very insightful music reproduction, now also because of your PSU. It would be nice at the end of your TSSA journey to show us final power supply schematic.
Very good job Mike.
Since some years now, I use another clever idea that -ECdesigns- created for his low power circuits but that I adapted for Hi power circuits: it is called "charge-transfer supply". It could add more clarity to an already transparent amp...
https://picasaweb.google.com/lh/photo/rOgiSl8IVgPdqOcKLPkbNNMTjNZETYmyPJy0liipFm0?feat=directlink
I use the cicuit until C2, then use my own regulator if needed.
I am sure you guys can optimize it for the SSA/TSSA. IMHO it is cheaper and smaller than a choke, and probably better. The drawback is that the first cap(bank) does not contribute to total capacitance, but I chose lower quality (cheaper) caps there. All my PS are "charge-transfered" now.
I hope you like it.
M.
PS: now I remember that I could see it work with my newly acquired scope...
https://picasaweb.google.com/lh/photo/rOgiSl8IVgPdqOcKLPkbNNMTjNZETYmyPJy0liipFm0?feat=directlink
I use the cicuit until C2, then use my own regulator if needed.
I am sure you guys can optimize it for the SSA/TSSA. IMHO it is cheaper and smaller than a choke, and probably better. The drawback is that the first cap(bank) does not contribute to total capacitance, but I chose lower quality (cheaper) caps there. All my PS are "charge-transfered" now.
I hope you like it.
M.
PS: now I remember that I could see it work with my newly acquired scope...
Hi maxlorenz
Thanky you, very nice circuit indeed. Only that it has to be adopted to higher currents for TSSA, offering serial mosfet impedance to control the charge of a first cap bank. Probably there's less spikes and HF interferences on second cap bank if compare to classic rectifier only.
Thanky you, very nice circuit indeed. Only that it has to be adopted to higher currents for TSSA, offering serial mosfet impedance to control the charge of a first cap bank. Probably there's less spikes and HF interferences on second cap bank if compare to classic rectifier only.