Hi MiiB
Since my SSA is more or less experimental project and Hawksford casode significantly lowers distortions compared to conventional one now present, I will put 2.0 version here soon ...
Hi MiiB
Since my SSA is more or less experimental project and Hawksford casode significantly lowers distortions compared to conventional one now present, I will put 2.0 version here soon ...
Hawksford cascode works very well. But it will lower the usable voltage swing due to the voltage drop. But you use a seperate supply to the frontend?!?
Here we are ;-)Since.. Hawksford casode significantly lowers distortions compared to conventional one now present, I will put 2.0 version here soon ...
True Balanced Differential
Andrej,
You are a
I just feel that something has to be happen and I'm really happy to hear these great news from You.
In the mean time I have an opportunity to borrow for a week-end an Electrocompaniet Nemo Mono blocks
(Pure Balanced Differential-from I/P to O/P).
The Source was also borrowed - True Balanced DSD, the same also for LP-Vinyl playback - The Sound ?? ==> Unforgettable . . . Such an Ultra Wide and Ultra Deep stage of orchestra I was never hear on any playback combination no mater who is the manufacturer, never heard on any HiEnd show all across Europe I was in the Past. I heard the best Wilson-Krel-Spectral combinations, Best MBL ones Magnepan-Krel, Nautilus-Krel-EL_C_Nemo, but Nemos on My Scintillas . . . it's totally different story . . . All the "HiEnd Sound" disappeared after some 1 hour or so from the first switch on and after that, the only what continues was the most relaxing and temperament live music which is filling my listening room. Why I'm telling all these my feelings here? because I was the most pleasantly musically feeded in my Life.
I just wonder to suggest to anyone who will have the opportunity to have a chance to hear the "REAL" full BALANCED SOUND ALL THE WAY FROM SOURCE to the LOUDSPEAKERS and if possible the Electrocompaniet NEMO Monos, then Please take some of Yours Precious time and GO LISTEN such a combination, No One will be disappointed . . .
I wonder to suggest to everyone who can afford the double cost of the components needed for the True Balanced stereo power amplifier (4xMono) just go for it even from the most simple one with + - 30V DC onward is worth investing, the $$ latter satisfaction will be enormous ! I can't listen non balanced system (SE) anymore - The difference in silence, stage width & depth is so huge that there's no way back !!
I'm pretty sure that all of those whoever had such a real true-complete full balanced experience at least once they'd know the real thing is only in true balanced system.
I was in a middle of my SSA V12 project when this happen to me and I was immediately know that there is no other way to continue - a must go with my project of Yours BRILLIANT SSA V12 only to a True Balanced - Differential Way.
Nemo Monos drives my Scintillas with such a musical elegance that I was in heaven all the time while I was listen to my most prefered Classical, Jazz, Old Rock, Reggae and all other Ethno music I consume the most.
Andrej, It Would be the most beautiful gift from You If the nonexistent time will allow You also to update the last SSA - V12 SCH published, to the Yours best latest findings from Yours experiences within the SSA You build. The OP Power section should keep the same +-50V DC supplies, for the driver section any needed DC voltage would be fine. Please update the Balanced version with the Thermal-drift stabilization which You use in Yours final build and the start-up circuit which You implement so nicely, would be much appreciated if the start-up SCH can be published also so I can implement it in my build of Yours final Balanced V12 SSA masterpiece.
All my findings written in this post about the full balanced play-back chain sound is intend only to share my experiences with all those who really practically have experiences with true balanced sound, so any never-ending debate about SE vs Balanced and to death complaints about what is best and optimum for home use is best to be avoided.
Andrej,
Thank You for Yours already great will, give and share, but knowing that SSA v2 is in the air . . it just fire a whole new nice fire in my soul.
Since my SSA is more or less experimental project and Hawksford casode significantly lowers distortions compared to conventional one now present, I will put 2.0 version here soon ...
Andrej,
You are a
I just feel that something has to be happen and I'm really happy to hear these great news from You.
In the mean time I have an opportunity to borrow for a week-end an Electrocompaniet Nemo Mono blocks
(Pure Balanced Differential-from I/P to O/P).
The Source was also borrowed - True Balanced DSD, the same also for LP-Vinyl playback - The Sound ?? ==> Unforgettable . . . Such an Ultra Wide and Ultra Deep stage of orchestra I was never hear on any playback combination no mater who is the manufacturer, never heard on any HiEnd show all across Europe I was in the Past. I heard the best Wilson-Krel-Spectral combinations, Best MBL ones Magnepan-Krel, Nautilus-Krel-EL_C_Nemo, but Nemos on My Scintillas . . . it's totally different story . . . All the "HiEnd Sound" disappeared after some 1 hour or so from the first switch on and after that, the only what continues was the most relaxing and temperament live music which is filling my listening room. Why I'm telling all these my feelings here? because I was the most pleasantly musically feeded in my Life.
I just wonder to suggest to anyone who will have the opportunity to have a chance to hear the "REAL" full BALANCED SOUND ALL THE WAY FROM SOURCE to the LOUDSPEAKERS and if possible the Electrocompaniet NEMO Monos, then Please take some of Yours Precious time and GO LISTEN such a combination, No One will be disappointed . . .
I wonder to suggest to everyone who can afford the double cost of the components needed for the True Balanced stereo power amplifier (4xMono) just go for it even from the most simple one with + - 30V DC onward is worth investing, the $$ latter satisfaction will be enormous ! I can't listen non balanced system (SE) anymore - The difference in silence, stage width & depth is so huge that there's no way back !!
I'm pretty sure that all of those whoever had such a real true-complete full balanced experience at least once they'd know the real thing is only in true balanced system.
I was in a middle of my SSA V12 project when this happen to me and I was immediately know that there is no other way to continue - a must go with my project of Yours BRILLIANT SSA V12 only to a True Balanced - Differential Way.
Nemo Monos drives my Scintillas with such a musical elegance that I was in heaven all the time while I was listen to my most prefered Classical, Jazz, Old Rock, Reggae and all other Ethno music I consume the most.
Andrej, It Would be the most beautiful gift from You If the nonexistent time will allow You also to update the last SSA - V12 SCH published, to the Yours best latest findings from Yours experiences within the SSA You build. The OP Power section should keep the same +-50V DC supplies, for the driver section any needed DC voltage would be fine. Please update the Balanced version with the Thermal-drift stabilization which You use in Yours final build and the start-up circuit which You implement so nicely, would be much appreciated if the start-up SCH can be published also so I can implement it in my build of Yours final Balanced V12 SSA masterpiece.
All my findings written in this post about the full balanced play-back chain sound is intend only to share my experiences with all those who really practically have experiences with true balanced sound, so any never-ending debate about SE vs Balanced and to death complaints about what is best and optimum for home use is best to be avoided.
Andrej,
Thank You for Yours already great will, give and share, but knowing that SSA v2 is in the air . . it just fire a whole new nice fire in my soul.
I 100% agree and run for symmetrical on all my equipment since decades.
(included the passive filter design in my enclosures).
Just a remark, using 2 single units as a bridged amp present an inconvenience, due to the power supplies differences. I feel better to use the same supply for the two units of a bridged amp.
Price to pay is the damping factor divided by 2 and too the impedance each amp has to drive I.e. ~3 ohms for an average 8 Ohm speaker.
X-BALANCED - SSA - V 12
@ Esperado,
Thank You for Yours real practical experience sharing as this is really a must to experience to anyone who wish to hear an feel a really the best & purest sound in it's own home environment in practice to be really "able" to believe, because any words counts only a little... but after that real world experience there's no way back.
- My need for low Ohmic Power-Amp drive ability is totally different from 99,99% of normal ordinary users and so dictates to me a very unique build to go...
From this lead I'm go to use a 4x 1,5 KW toros for the OPS separately (already have them) and an additional
4x 25OW toros or R-Cores for the driver-stages - a true full balanced-differential flow all the way.
From my experiences till now the pure balanced diferential flow will be the most pure to signal approach to follow including at the end the X-Balanced SSA.. . .
@mikelm
Including Yours statements to the X-balanced design then . . . .
This way the whole playback chain would be the total top of the top for any SSA Built ever.
Hopefully the Mr. ==-> - - <-== will read all this ...
With all my best wishes to You
Andrej,
to the scene and to all real "music" lovers...
@ Esperado,
Thank You for Yours real practical experience sharing as this is really a must to experience to anyone who wish to hear an feel a really the best & purest sound in it's own home environment in practice to be really "able" to believe, because any words counts only a little... but after that real world experience there's no way back.
- My need for low Ohmic Power-Amp drive ability is totally different from 99,99% of normal ordinary users and so dictates to me a very unique build to go...
From this lead I'm go to use a 4x 1,5 KW toros for the OPS separately (already have them) and an additional
4x 25OW toros or R-Cores for the driver-stages - a true full balanced-differential flow all the way.
From my experiences till now the pure balanced diferential flow will be the most pure to signal approach to follow including at the end the X-Balanced SSA.. . .
@mikelm
Including Yours statements to the X-balanced design then . . . .
This way the whole playback chain would be the total top of the top for any SSA Built ever.
Hopefully the Mr. ==->
- - <-== will read all this ...With all my best wishes to You
Andrej,
to the scene and to all real "music" lovers...
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A test with a practical device unveiled that thermal compensation is not optimal.
In fact an overcompensation happens. Thus after a sine burst with a signal amplitude such that the max power dissipation is reached (Vcc²/pi²*Rl) for each BJT followed by a burst with low amplitude I see crossover distortion
as the quiescent current fell to 10 mA from 78 mA. Thus the Vbe multiplier must not be in thermal contact with a heatsink for the drivers ( not for the power BJT) to compensate for their junction temp.
This is the effect noticed by P. Walker which led him to develop the famous Quad 303 triple cascade "supertransistor".
Without thermal trak diodes a Vbe multiplier mounted on the heatsink would "see" temperatures from events in the past as "heat travels" by diffusion.
If one wants perfect reproduction of "dynamic structures" and is less obliged with lowest thd in steady state this behavior is not tolerable.
Thus this thermal trak compensation requires more research.
The goal is to keep the voltage drop across the emitter resistor constant at 26 mV.
Otherwise the amp is good enough, open loop bandwidth is set to 100 kHz
and thd is about 0.02% on real load, but could get better at complex loads.
Anyway this EF does not take advantage from the excellent ß/ic linearity
of the Eon thermal trak devices , a linearity btw. unmatched by tubes or FETs.
Thus in a final version the BJTs must be current controlled that is a current source should force the base current with non linear Vbe following but having no effect on distortion.
Yes, +/-72 V for the front-end and +/-62 V for the output, so cascode modification wouldn't reduce an output swing for a bit.
Hi Smiley
I didn't forget about balanced SSA HP V12, it will be updated with all the latest upgrade details and small improvements from the real circuit. So I kindly ask you to wait a little more until a base core of the SSA will be up to the highest performance level as expected.
@ Esperado,
Thank You for Yours real practical experience sharing as this is really a must to experience to anyone who wish to hear an feel a really the best & purest sound in it's own home environment in practice to be really "able" to believe, because any words counts only a little... but after that real world experience there's no way back.
- My need for low Ohmic Power-Amp drive ability is totally different from 99,99% of normal ordinary users and so dictates to me a very unique build to go...
From this lead I'm go to use a 4x 1,5 KW toros for the OPS separately (already have them) and an additional
4x 25OW toros or R-Cores for the driver-stages - a true full balanced-differential flow all the way.
From my experiences till now the pure balanced diferential flow will be the most pure to signal approach to follow including at the end the X-Balanced SSA.. . .
@mikelm
Including Yours statements to the X-balanced design then . . . .
This way the whole playback chain would be the total top of the top for any SSA Built ever.
Hopefully the Mr. ==->
With all my best wishes to You
Andrej,
to the scene and to all real "music" lovers...
Balanced amplifier combined from two single channels, demands that one single channel to be as good as possible. Stability and low output impedance are of utmost importance characteristics from a single channel to be part of balanced amplifier. Stability is not an issue for SSA, checked many times from the latest channels under test, also output impedance is fairly low, measured 5,6 mohm at 20 kHz.
Now I'm testing the SSA with no gate stoppers and all measurements showed better performance at high frequency with no instability noticed. If sound check will be in the same direction, this will stay.
The same with VAS enhanced cascodes modifications, if proved to be better sounding amp than they will be incorporated in the schematic.
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Indeed
Please guys some comments about Hawksford cascode in attached circuits. Will there be any difference between a. and b. schematics performance?
Attachments
This is the first version that lacks some elegance . But data ( simulation) are very nice
nothing to complain. No oscillation on complex loads ( simulated 3 way passive crossover with simulated speakers) . Good thd spectrum but not very good. Could be tweaked to some degree by variation of predriver and Vas op.
Sensitivity to changes of complex loads average.
Will route a PCB . The predriver BJTs and the zeners will be placed on a heatsink held at 70 degrees by simple thermostate circuitry.
Transistors Q2 Q4 (B139 BD140) will be replaced by BC639 BC640 or Japan types with higher Vce max Vcb max ( 150 Volts and up) . Ole CRT video BJTs out of stock.
nothing to complain. No oscillation on complex loads ( simulated 3 way passive crossover with simulated speakers) . Good thd spectrum but not very good. Could be tweaked to some degree by variation of predriver and Vas op.
Sensitivity to changes of complex loads average.
Will route a PCB . The predriver BJTs and the zeners will be placed on a heatsink held at 70 degrees by simple thermostate circuitry.
Transistors Q2 Q4 (B139 BD140) will be replaced by BC639 BC640 or Japan types with higher Vce max Vcb max ( 150 Volts and up) . Ole CRT video BJTs out of stock.
Attachments
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... so tracking (Hawksford) cascode at the input as well. Some decoupling for the series diodes?
BTW nice criss-cross connections Just measured output impedance without gate stoppers: 4,7 mohm/20 kHz. Razor sharp square pulses at 100 kHz/4 ohm
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