Heard (a prototype of) this new amp from Hugh Dean last night at a demonstration at the Melbourne Audio Club. Along with a pair of 3-way "adjustable" speakers, this was commented on as being the "best sound" that people had heard for many years. It should be noted that the room itself doesn not really lend itself to audio demonstrations.
The speaker itself was made up of a Peerless XXLS 10" in a 65 litre passive radiator (for the first part of the night) and 65 litre sealed (for the remainder) - a Vifa P13WH in a sealed box (for the first few tracks) and then open backed with Tontine stuffing (fro the remainder that I was there) - a Scanspeak D2904 along with an Optimus dipole tweeter. The crossover is a first-order series between mid and bass (plus a zobel for each), and this is crossed (as a whole) to the tweeter using a third-order parallel crossover. The Optimus is used as the resistor in the zobel for the Scanspeak tweeter, or can be switched out. Told you it was "adjustable"...
The amp was displayed, open topped, and was very simple and well laid out and "pretty" to look at. And drove the speakers (in all configurations) with control and authority - which is not something that all amplifiers could do (IMHO). It did pretty much what all amplifiers should do - disappeared.
The speaker itself was made up of a Peerless XXLS 10" in a 65 litre passive radiator (for the first part of the night) and 65 litre sealed (for the remainder) - a Vifa P13WH in a sealed box (for the first few tracks) and then open backed with Tontine stuffing (fro the remainder that I was there) - a Scanspeak D2904 along with an Optimus dipole tweeter. The crossover is a first-order series between mid and bass (plus a zobel for each), and this is crossed (as a whole) to the tweeter using a third-order parallel crossover. The Optimus is used as the resistor in the zobel for the Scanspeak tweeter, or can be switched out. Told you it was "adjustable"...
The amp was displayed, open topped, and was very simple and well laid out and "pretty" to look at. And drove the speakers (in all configurations) with control and authority - which is not something that all amplifiers could do (IMHO). It did pretty much what all amplifiers should do - disappeared.
Cloth Ears,
Short,sweet and to the point, aurally disappearing is one of the many things this amplifier does well. It does what it should do, play music as it is naturally, without obstruction or a sonic imprint from the gear itself causing you to get lost in and focus on the music, I have been enjoying listening to all of my old recordings that have become new once again with details once hidden .
Colin
Short,sweet and to the point, aurally disappearing is one of the many things this amplifier does well. It does what it should do, play music as it is naturally, without obstruction or a sonic imprint from the gear itself causing you to get lost in and focus on the music, I have been enjoying listening to all of my old recordings that have become new once again with details once hidden .
Colin
The other thing that was good about it in this particular demonstration, was that we were able to listen to the changes brought about by the various combinations of the speaker set-up (it's really quite ingenious) without having to put up with the limitations of the amplifier in being able to driver the crossover/driver combination. OK, so we didn't have a Apogee Scintilla to really test its' driving abilities 
. Nothing worse than having an amplifer blow a fuse when you ask it to drive 1 ohm loads 
.
. Nothing worse than having an amplifer blow a fuse when you ask it to drive 1 ohm loads .
Thanks Jont, Colin and Carlos! It was a good night and I was pleased. The speaker was a doddle to drive, it was so well designed.
The Soraya CB105 is extraordinarily load tolerant. I took an Acustat recently to almost destructive levels and the amp didn't raise a sweat. There is no sonic influence at all with a 0.47uF cap switched across the speaker while playing, with no sign of instability when viewed on the CRO.
This amp will be exhibited at Denver RMAF with Ellis 1801b speakers and I welcome any member here to have a listen - particularly those who feel these achievements are not credible! (Andy, can I buy you a beer??)
Ciao,
Hugh
The Soraya CB105 is extraordinarily load tolerant. I took an Acustat recently to almost destructive levels and the amp didn't raise a sweat. There is no sonic influence at all with a 0.47uF cap switched across the speaker while playing, with no sign of instability when viewed on the CRO.
This amp will be exhibited at Denver RMAF with Ellis 1801b speakers and I welcome any member here to have a listen - particularly those who feel these achievements are not credible! (Andy, can I buy you a beer??)
Ciao,
Hugh
Hi Daniel,
I'm moving towards an ultra low distortion model. New amp has 15 devices per channel, quite complex. I've found that huge quality gains are possible by better controlling very low amplitude signals, around the dead zone of crossover. Feedback is now nested, and compensation is quite complex. It's an amp I'm pleased with, certainly, but will only sell as a retail product.
Trust you are well!
Hugh
I'm moving towards an ultra low distortion model. New amp has 15 devices per channel, quite complex. I've found that huge quality gains are possible by better controlling very low amplitude signals, around the dead zone of crossover. Feedback is now nested, and compensation is quite complex. It's an amp I'm pleased with, certainly, but will only sell as a retail product.
Trust you are well!
Hugh
yes i am fine - thank You - LF is working very nice from the day one (well, actually since it was burned in completely)...
now i am playing with some power amplifier designs that i would like to build ...one is on the way....we will see....of course LF will be the reference...
15 devices...wow....nice....nested feedback ..... nice....
now i am playing with some power amplifier designs that i would like to build ...one is on the way....we will see....of course LF will be the reference...
15 devices...wow....nice....nested feedback .....
nice....
Hi Sparkle,
15 devices that work together to pass through with gain some of the
most lucid and involving sonics to ever pass by these ears ever!, all without any hint of typical SS glare and edginess that is often associated with a transistor design. To be able to do this, without added coloration and with very low distortion is a wonderful combination. I hope Hugh the best on this one as he has nailed it in sonics and realism that is hard to beat and possibly unsurpassed in the nth degree. and I feel will be a rose smelling time to some EE's, further proof that a design should be met by both ears and measurements, but finalised by ear.
Best Wishes
Colin
15 devices that work together to pass through with gain some of the
most lucid and involving sonics to ever pass by these ears ever!, all without any hint of typical SS glare and edginess that is often associated with a transistor design. To be able to do this, without added coloration and with very low distortion is a wonderful combination. I hope Hugh the best on this one as he has nailed it in sonics and realism that is hard to beat and possibly unsurpassed in the nth degree. and I feel will be a rose smelling time to some EE's, further proof that a design should be met by both ears and measurements, but finalised by ear.
Best Wishes
Colin
that is really good Colin,
i am happy for you and i wish all the best for Hugh...
i have Lifeforce and i am very happy with it...sounds nice with my tube preamplifer....
Soraya seems to be ultra super turbo upgrade on the LF sound....
this makes me a bit sad - makes me wanna jump out of couriosity - but still i am also very happy for Hugh....
i am happy for you and i wish all the best for Hugh...
i have Lifeforce and i am very happy with it...sounds nice with my tube preamplifer....
Soraya seems to be ultra super turbo upgrade on the LF sound....
this makes me a bit sad - makes me wanna jump out of couriosity - but still i am also very happy for Hugh....
The best part and the worst part is that Hugh already made another design...and this
one is said by him to be even better than Soraya.
It is an Ultra low distortion design, different than Soraya but having some circuits from this one...ahahahahha...the OLD Soraya.
This is good, as we have a new, and better amplifier...almost unbeliavable to me that he could make, and once again, and by the fouth time, something even better ...but he said this last one is better..... well, he has proved many times that his words deserves confidence.
I am not sure the model he mailed, in advance, to Denver.
We, .... Aksa lovers.... now we have to jump even more ...jumping higher and filled with curiosity, envy, jellows and all human natural feelings, positive or negative ones....the most funny is that we are jumping for something already second place into Hugh line.
This is a constant... normally happens...when he start to give us informs, to the more close friends, about his circuits, is because he has another one "only for his eyes".
I have received some informs about Soraya and i could listen to it...and i think Colin also, do not know exactly if he has the Soraya model or other model in his home... and this happened when he was finishing to "cook" into his brain, the Ultra Low distortion new model.
Well...he is in the Denver fair, at Colorado, USA..... smilling and confident, a huge man, very important to our communitty.
I really think, despite i love USA, that is a big honor, for them, to receive Hugh Dean in their land.
I ensure you..if he land here, i will provide red carpet and a band playing Australian music...with flags and pretty girls to welcome him.
I will be there to polish his shoes..for sure i will.
In one year, or a little bit less, we gonna start to have top secret informs.... into the rule of "the secret of the secret" that we all know, close friends...and this will be showing me, finally, that he will be producing another new schematic.
His customers have fidelity.... he has just to announce a new model and they run to order.. also they ask for the cost ijn second place..not a condition to order anymore...so...he can produce the ammount of models he wants.... the confidence he already have is strong as a diamond.
Interesting how we behave, normal humans..our damn envy, jellows and our bad side....in our forum he was smashed many times, criticised....people had smashed him hard.... read all forum and you will see..in the place to open their ears and listen for a day to learn some...they attacked him with theories and a lot of foolishes, that in the practice work just do not works, or work bad or sound bad.
Now a days he is buying his car number five, his bike number two, travelling to foreign countries, spending a lot of money having nice dinner with friends, customers and family, crossing Australia with his high speed bike, having a confortable life....no!...no!...no!...everyone can use a credit card and pay all those expenses into 10 years....he does his payment in c-a-s-h.
And while, those ones that bothered him are already trying to bother others.... they have learned nothing related audio, and have learned nothing related good behavior, how control the envy.... how to control their pride.
They think they are special...for sure they are.. in the negative way.
Maybe their profession.... to bother....botherneers.
regards,
Carlos
one is said by him to be even better than Soraya.
It is an Ultra low distortion design, different than Soraya but having some circuits from this one...ahahahahha...the OLD Soraya.
This is good, as we have a new, and better amplifier...almost unbeliavable to me that he could make, and once again, and by the fouth time, something even better ...but he said this last one is better..... well, he has proved many times that his words deserves confidence.
I am not sure the model he mailed, in advance, to Denver.
We, .... Aksa lovers.... now we have to jump even more ...jumping higher and filled with curiosity, envy, jellows and all human natural feelings, positive or negative ones....the most funny is that we are jumping for something already second place into Hugh line.
This is a constant... normally happens...when he start to give us informs, to the more close friends, about his circuits, is because he has another one "only for his eyes".
I have received some informs about Soraya and i could listen to it...and i think Colin also, do not know exactly if he has the Soraya model or other model in his home... and this happened when he was finishing to "cook" into his brain, the Ultra Low distortion new model.
Well...he is in the Denver fair, at Colorado, USA..... smilling and confident, a huge man, very important to our communitty.
I really think, despite i love USA, that is a big honor, for them, to receive Hugh Dean in their land.
I ensure you..if he land here, i will provide red carpet and a band playing Australian music...with flags and pretty girls to welcome him.
I will be there to polish his shoes..for sure i will.
In one year, or a little bit less, we gonna start to have top secret informs.... into the rule of "the secret of the secret" that we all know, close friends...and this will be showing me, finally, that he will be producing another new schematic.
His customers have fidelity.... he has just to announce a new model and they run to order.. also they ask for the cost ijn second place..not a condition to order anymore...so...he can produce the ammount of models he wants.... the confidence he already have is strong as a diamond.
Interesting how we behave, normal humans..our damn envy, jellows and our bad side....in our forum he was smashed many times, criticised....people had smashed him hard.... read all forum and you will see..in the place to open their ears and listen for a day to learn some...they attacked him with theories and a lot of foolishes, that in the practice work just do not works, or work bad or sound bad.
Now a days he is buying his car number five, his bike number two, travelling to foreign countries, spending a lot of money having nice dinner with friends, customers and family, crossing Australia with his high speed bike, having a confortable life....no!...no!...no!...everyone can use a credit card and pay all those expenses into 10 years....he does his payment in c-a-s-h.
And while, those ones that bothered him are already trying to bother others.... they have learned nothing related audio, and have learned nothing related good behavior, how control the envy.... how to control their pride.
They think they are special...for sure they are.. in the negative way.
Maybe their profession.... to bother....botherneers.
regards,
Carlos
Attachments
HI Carlos,
The model that I am using is the Soraya CB105, which has time and time again sounded great from fire up into being warmed up, you can listen from the first 3 seconds after turning the unit on and be graced with incredible sonics, I love this amplifier. Haha, its all possible that Hugh has an idea for a better amplifier, or perhaps has even built one but listening to the CB105 sounds like an Ultra Low distortion amplifier to these ears, the first hint being the change from recording to recording that is played, the tonal aspects and differences of each simlar instrument, brand of instruments is easily perceived alowing deep insight into the session that was recorded. Low level details are strikingly clear, without the tizz factor that often creeps up in some other designs, here the highs are clear, natural and silky without sounding etched. The Bass is weighty, yet at the same time very clear and natural and tightly controlled, wheras many amplifiers will create low end doing so the detail is usually lost, here I can feel the bass along with the resolution that gives away the technique used, and or left hand fret sloppiness on occasion. Imaging is awesome and 3D placement is very realistic, and remains so even through modest speakers, special effects recorded into music can often startle and make you almost jump across the room in its realism. Vocals are crisp with clairity but never get edgy, I havent built one amplifier or owned one in the past that could ever do justice to female vocals, it seemed to be commonplace that they wouuld present some distortion on peaks that was often unpleasent but not this one, I have never enjoyed listening to these CD's more than i do now and being able to be free from that ear assualt.
If I am correct, the model going to Denver is this one, some lucky souls in the US will get to hear it. Carlos, put your shoe polish away and roll the red carpet up and just shake Hugh's hand, haha, and thank him for consistently caring about our ears!. Hugh is a nice person, a humble yet confident person and has many good reasons to rightfully be, but at the end of the day he is a normal person like you and I with dreams and the ability to listen and teach very well!!.Carlos tell the band to cut back on the AC/DC and Midnight Oil Covers .
Best Wishes
Colin
The model that I am using is the Soraya CB105, which has time and time again sounded great from fire up into being warmed up, you can listen from the first 3 seconds after turning the unit on and be graced with incredible sonics, I love this amplifier. Haha, its all possible that Hugh has an idea for a better amplifier, or perhaps has even built one but listening to the CB105 sounds like an Ultra Low distortion amplifier to these ears, the first hint being the change from recording to recording that is played, the tonal aspects and differences of each simlar instrument, brand of instruments is easily perceived alowing deep insight into the session that was recorded. Low level details are strikingly clear, without the tizz factor that often creeps up in some other designs, here the highs are clear, natural and silky without sounding etched. The Bass is weighty, yet at the same time very clear and natural and tightly controlled, wheras many amplifiers will create low end doing so the detail is usually lost, here I can feel the bass along with the resolution that gives away the technique used, and or left hand fret sloppiness on occasion
. Imaging is awesome and 3D placement is very realistic, and remains so even through modest speakers, special effects recorded into music can often startle and make you almost jump across the room in its realism. Vocals are crisp with clairity but never get edgy, I havent built one amplifier or owned one in the past that could ever do justice to female vocals, it seemed to be commonplace that they wouuld present some distortion on peaks that was often unpleasent but not this one, I have never enjoyed listening to these CD's more than i do now and being able to be free from that ear assualt.If I am correct, the model going to Denver is this one, some lucky souls in the US will get to hear it
. Carlos, put your shoe polish away and roll the red carpet up and just shake Hugh's hand, haha, and thank him for consistently caring about our ears!. Hugh is a nice person, a humble yet confident person and has many good reasons to rightfully be, but at the end of the day he is a normal person like you and I with dreams and the ability to listen and teach very well!!.Carlos tell the band to cut back on the AC/DC and Midnight Oil Covers .Best Wishes
Colin
The model I listened to a couple of weeks ago was (I think)the 'prototype' that is going to be in the Denver show. We got to have a listen before Hugh took it away to America for the first public listen. I do not think I have heard the previous version (or indeed any AKSA since the 55w version of a few years ago).
My impressions are, therefore, not based on much previous experience with AKSA, Lifeforce or any other Hugh Dean amplifier. Just that night.
Carna Cats (if Hughs' listening)!
My impressions are, therefore, not based on much previous experience with AKSA, Lifeforce or any other Hugh Dean amplifier. Just that night.
Carna Cats (if Hughs' listening
)!Hello
Hugh, you should come in Canada, lots of guy's in Montreal and Toronto would love to ear the Soraya amp.
Each years, in April, in Montreal in Quebec province, there is the Festival Son et Image, arround 9,000 to 10,000 visitors, english and french speaking, in the Sheraton Hotel Centre.
Here's the web site of the Festival Son et Image, next expo are around the April 3 /2008 ;
http://www.fsiexpo.com/2007/b/index_EN.html
Would be nice to see you there Hugh.
Gaetan
Hugh, you should come in Canada, lots of guy's in Montreal and Toronto would love to ear the Soraya amp.
Each years, in April, in Montreal in Quebec province, there is the Festival Son et Image, arround 9,000 to 10,000 visitors, english and french speaking, in the Sheraton Hotel Centre.
Here's the web site of the Festival Son et Image, next expo are around the April 3 /2008 ;
http://www.fsiexpo.com/2007/b/index_EN.html
Would be nice to see you there Hugh.
Gaetan
Hi Jont,
As far as I know there is no previous version aside from the LifeForce modules, I think Carlos may be having some good ol fun amongst here. The Soraya was the first Aspen amplifier that I have heard and I think we are at par with eachother for experience at hearing the Aspen line, Im sure if I lived in Melbourne i would be able to say different and based upon this experience its hard to approach DIY amplifiers as I know just how much searching is in the horizon to even attempt to do anywhere close to better, even at that better may just mean different.
Best Wishes
Colin
As far as I know there is no previous version aside from the LifeForce modules, I think Carlos may be having some good ol fun amongst here
. The Soraya was the first Aspen amplifier that I have heard and I think we are at par with eachother for experience at hearing the Aspen line, Im sure if I lived in Melbourne i would be able to say different and based upon this experience its hard to approach DIY amplifiers as I know just how much searching is in the horizon to even attempt to do anywhere close to better, even at that better may just mean different. Best Wishes
Colin
Hi Colin, Jont, Gaetan,
The Lifeforce has been on the scene since late last year as assembled modules, the Soraya only about a month.
The one you heard, Jont, was built for a local customer, and is one of two now in Melbourne. A third was built last week for US mains and is now in Omaha with David Ellis, and will be the demo amp for RMAF at Denver.
The new amp has 15 transistors per channel for 200W into 4R. It is quite complex despite maniacal attempts to make it simpler. I dislike complexity, nevertheless it subscribes to Einstein's famous maxim, and performs extremely well both subjectively and objectively. It uses low impedance lag comp, high impedance feedback node, nested feedback and phase lead, and even a few SMDs. It is very robust and will withstand indefinite output shorting with low level signals without too much in the way of protective circuitry.
I suppose the best description of the sound is resolving and transparent, with decay down to vanishingly low levels. You can easily discern, for example, different types and brands of piano and brass. It is easy to get very subjective and fill the world with smoke when trying to describe sound.
OTOH, distortion figures are around 0.008% at full power into 8R/1KHz although I really need to examine the spectrum in precise detail. Feedback factor is extremely high, up around 70dB. I have found that this amp is unconditionally stable into electrostatic speakers, and one owner is using it for Acoustats very satisfactorily. I'm very pleased with the ability to drive almost any load, but I do admit to using an output inductor of 1.4uH.
Thank you for the interest,
Hugh
The Lifeforce has been on the scene since late last year as assembled modules, the Soraya only about a month.
The one you heard, Jont, was built for a local customer, and is one of two now in Melbourne. A third was built last week for US mains and is now in Omaha with David Ellis, and will be the demo amp for RMAF at Denver.
The new amp has 15 transistors per channel for 200W into 4R. It is quite complex despite maniacal attempts to make it simpler. I dislike complexity, nevertheless it subscribes to Einstein's famous maxim, and performs extremely well both subjectively and objectively. It uses low impedance lag comp, high impedance feedback node, nested feedback and phase lead, and even a few SMDs. It is very robust and will withstand indefinite output shorting with low level signals without too much in the way of protective circuitry.
I suppose the best description of the sound is resolving and transparent, with decay down to vanishingly low levels. You can easily discern, for example, different types and brands of piano and brass. It is easy to get very subjective and fill the world with smoke when trying to describe sound.
OTOH, distortion figures are around 0.008% at full power into 8R/1KHz although I really need to examine the spectrum in precise detail. Feedback factor is extremely high, up around 70dB. I have found that this amp is unconditionally stable into electrostatic speakers, and one owner is using it for Acoustats very satisfactorily. I'm very pleased with the ability to drive almost any load, but I do admit to using an output inductor of 1.4uH.
Thank you for the interest,
Hugh
AKSA said:
Hello Hugh
OK, it would be a canadian buyer who would show it as a demo amp here in Canada. Sad that I can not afford that amp.
70 db nfb !! Wow that's need a very good slew rate, but I'm shure that your nfb work fast and without lot of phase change in the end result. I'm also sure that the distortion figure are still low at high frequency and at very low level output, that's some of the key factors for very good sounding amp and your amps are in the best.
Hummm, I suspect that you did have some long night of thinking to made that marvel.
Bye
Gaetan
Carlos,
My apologies for not mentioning you in my last email. I was dog tired and there were so many positive comments in your post that I was confused and a little embarassed!! Thank you for the post, you are right about most things, but there is nothing to beat the Soraya, believe me!
Gaetan,
Let me comment conceptually about stability. Bode and Nyquist determined mathematically that in a feedback amplifier it would be unconditionally stable if, at the frequency where phase shift is 180 degrees, also called the pole frequency, the open loop gain of the amp dropped below unity. The reason is that if the output of the amp is 180 degrees phase inverted to the input because of phase shift (the reciprocal of phase shift is called group delay) then negative feedback, which pulls back output, is now positive feedback, which adds to output. When the signal itself adds to the normal gain of the amp, it quickly alternately latches to the rail and becomes a crude oscillator. So steps must be taken to pull back the gain of the voltage amplifier to keep gain below unity at the pole frequency.
The pole is typically about 500-900 KHz on an audio amp, though it obviously varies widely according to topology and devices chosen. If open loop gain is around 180,000 - a typical figure - then this has to be pulled back a LONG way to get to unity by this high frequency. The normal way to do this is by lag compensation, a simple cap from collector to base of the VAS. It's appallingly simple, but it works.
Except there are problems. Cap size is absolutely critical. Too big and the amp sounds slow and leaden. Too low and it sound tizzy, bright and fatigueing, and does NOT handle difficult loads at all well. There is room for improvement.
Linsley Hood suggested phase lead, which is a small cap from the collector of the VAS to the feedback node. This introduces an inverse phase shift into the amp which nulls the phase shift of a reactive (usually capacitive) load. If the criticality of the lag comp is not enough, adding a phase lead cap complicates the math enormously and is profoundly affected by layout as well. For this reason, these values are usually arrived at empirically. Compensating an amp is something of a black art, and very difficult to do, because it's a compromise like most critical aspects of engineering.
I hope this helps in your quest for the perfect amp! Persevere, you might get there, this is a difficult art!
If you can get to Vancouver, I'm sure Colin would be pleased to play the Soraya to you, let me know and I will ask!
Cheers,
Hugh
My apologies for not mentioning you in my last email. I was dog tired and there were so many positive comments in your post that I was confused and a little embarassed!! Thank you for the post, you are right about most things, but there is nothing to beat the Soraya, believe me!
Gaetan,
Let me comment conceptually about stability. Bode and Nyquist determined mathematically that in a feedback amplifier it would be unconditionally stable if, at the frequency where phase shift is 180 degrees, also called the pole frequency, the open loop gain of the amp dropped below unity. The reason is that if the output of the amp is 180 degrees phase inverted to the input because of phase shift (the reciprocal of phase shift is called group delay) then negative feedback, which pulls back output, is now positive feedback, which adds to output. When the signal itself adds to the normal gain of the amp, it quickly alternately latches to the rail and becomes a crude oscillator. So steps must be taken to pull back the gain of the voltage amplifier to keep gain below unity at the pole frequency.
The pole is typically about 500-900 KHz on an audio amp, though it obviously varies widely according to topology and devices chosen. If open loop gain is around 180,000 - a typical figure - then this has to be pulled back a LONG way to get to unity by this high frequency. The normal way to do this is by lag compensation, a simple cap from collector to base of the VAS. It's appallingly simple, but it works.
Except there are problems. Cap size is absolutely critical. Too big and the amp sounds slow and leaden. Too low and it sound tizzy, bright and fatigueing, and does NOT handle difficult loads at all well. There is room for improvement.
Linsley Hood suggested phase lead, which is a small cap from the collector of the VAS to the feedback node. This introduces an inverse phase shift into the amp which nulls the phase shift of a reactive (usually capacitive) load. If the criticality of the lag comp is not enough, adding a phase lead cap complicates the math enormously and is profoundly affected by layout as well. For this reason, these values are usually arrived at empirically. Compensating an amp is something of a black art, and very difficult to do, because it's a compromise like most critical aspects of engineering.
I hope this helps in your quest for the perfect amp! Persevere, you might get there, this is a difficult art!
If you can get to Vancouver, I'm sure Colin would be pleased to play the Soraya to you, let me know and I will ask!
Cheers,
Hugh
AKSA said:
Hello Hugh
The lag compensation or Miller cap alway's seem, for me, as a high frequency local nfb in the VAS, since the VAS are the most important step for the signal voltage amplification for the drivers, if the value of the cap are too big, that VAS nfb are cuting lower than the pole frequency and cut down into high frequencies who are important for good listening. And if the cap his too big it cut higher than the pole frequency and the amp oscillate, do I'm right ?
Thank
Gaetan
Hi Gaetan,
Yes, you have it...... but a strange thing happens; if the lag comp cap is not the optimum value, the entire audio band is seriously affected, bass right through to top end. This is a surprise to me, but there it is.
Please excuse my late reply, I'm preparing for RMAF and a little busy!
Hugh
Yes, you have it...... but a strange thing happens; if the lag comp cap is not the optimum value, the entire audio band is seriously affected, bass right through to top end. This is a surprise to me, but there it is.
Please excuse my late reply, I'm preparing for RMAF and a little busy!
Hugh
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