Corresponded with Randy on audio and his personal faith. Very passionate about all he believed in. He sent me a copy of the first 3 chapters of a book he wrote but did not make public, "A Heresy of (by) fire". If someone has the rest of the 12 or 14 chapters of this book, I would like to hear from them. Thanks.
His Optimos amps I have with me are among the best I've heard.
I have lost a very dear friend, though we never met in person.
Goodbye my friend. Will see you someday on the other shore. My condolences to his family.
His Optimos amps I have with me are among the best I've heard.
I have lost a very dear friend, though we never met in person.
Goodbye my friend. Will see you someday on the other shore. My condolences to his family.
Received the sad news from ZUS Audio today. Very saddened. I requested one of his books as a Christmas gift December 2009, read it, enjoyed it thoroughly and felt relatively enlightened as a newcomer to amplifier DIY. I plan to buy his other books. What a great loss. My condolences to his family and all his loved ones.
Tribute to Randy Slone
It was a real joy conversing and then eventually meeting Randy. I came to know him as a man with such a warm heart, a very giving and considerate person, a brilliant (genius level) audio engineer and having a passion for bringing the highest performance audio gear to the masses. Randy had an incredible grasp, understanding and knowledge of analogue audio design. Randy was very humble and modest. I really believe Randy did not see his own genius. In fact, he often told me that he has really not done anything special in his designs. I had to remind him of how amazing his audio designs were (are) and how many people have had the great pleasure of hearing true high-end audio. When one hears a Slone/ZUS Amp, it is an experience not soon forgotten. Randy and I had numerous and oftentimes very lengthy telephone conversions. Topics were not surprisingly centered on current and future audio designs. (Once while chatting on the phone, I found out that Randy’s IQ was close to 180. A humble man indeed.)
Before his passing, Randy got real excited about an audio amplifier design breakthrough. He told me that he had envisioned a way to finally eliminate all distortion-causing mechanisms in an audio amplifier. He couldn’t wait to run SPICE simulations to test out his new theory.
After few days Randy called me with excitement in his breath – the new design approach worked! Randy built up a prototype amplifier to test the theoretical against the empirical. Testing the amp on his audio spectrum analyzer proved his concept was indeed a breakthrough. One of the largest contributors of distortion in a Class B amplifier is the crossover distortion. Randy was able to eliminate crossover distortion in Class B amplifiers. This is a truly remarkable achievement. This is primarily what distinguishes Class A from Class B – Class A has zero crossover distortion, yet is Class A is woefully inefficient. Now comes a Class B amp, that performs like a Class A amp, yet with three-times better efficiency. There were other subtle distortion-causing mechanisms that Randy’s new circuit also either reduced or eliminated entirely.
Sadly, Randy never fully completed this design and no one has ever heard it in action. In Randy’s laboratory, this breakthrough amplifier however, was setting a new benchmark in audio performance.
Fortunately, Randy emailed me the schematic before he passed on. I cannot tell whether the schematic I have is 100% tweaked, as I do not have Randy’s amazing understanding of analogue audio, but from what I can tell it looks exquisite. In fact, it looks like a work-of-art as what a master artist could only draw.
Few knew this, but Randy was a Trekkie (Star Trek fan) since the original Star Trek television show aired back in the late 60’s (1966 to be exact). He loved the original shows, and never really cared for the sequels. He would relax to re-runs of the old Star Trek series. Didn’t matter to Randy if he’d seen the episode for the hundredth-time…he was as captivated as if viewing for the first time.
Randy also had a deep religious faith, which helped console him through his many hardships. A truly multi-facetted individual, with whom could relate to almost everyone on one subject or another.
Randy was also an accomplished banjo player. His love of audio extended to the creation of music as well as the electrical reproduction of it. This allowed Randy to lend a critical ear to the performance of his audio gear. Randy gave a huge gift to the audio community. He will be remembered, admired and loved. Godspeed to your new shores my friend.
Russ
ZUS Audio Inc.
It was a real joy conversing and then eventually meeting Randy. I came to know him as a man with such a warm heart, a very giving and considerate person, a brilliant (genius level) audio engineer and having a passion for bringing the highest performance audio gear to the masses. Randy had an incredible grasp, understanding and knowledge of analogue audio design. Randy was very humble and modest. I really believe Randy did not see his own genius. In fact, he often told me that he has really not done anything special in his designs. I had to remind him of how amazing his audio designs were (are) and how many people have had the great pleasure of hearing true high-end audio. When one hears a Slone/ZUS Amp, it is an experience not soon forgotten. Randy and I had numerous and oftentimes very lengthy telephone conversions. Topics were not surprisingly centered on current and future audio designs. (Once while chatting on the phone, I found out that Randy’s IQ was close to 180. A humble man indeed.)
Before his passing, Randy got real excited about an audio amplifier design breakthrough. He told me that he had envisioned a way to finally eliminate all distortion-causing mechanisms in an audio amplifier. He couldn’t wait to run SPICE simulations to test out his new theory.
After few days Randy called me with excitement in his breath – the new design approach worked! Randy built up a prototype amplifier to test the theoretical against the empirical. Testing the amp on his audio spectrum analyzer proved his concept was indeed a breakthrough. One of the largest contributors of distortion in a Class B amplifier is the crossover distortion. Randy was able to eliminate crossover distortion in Class B amplifiers. This is a truly remarkable achievement. This is primarily what distinguishes Class A from Class B – Class A has zero crossover distortion, yet is Class A is woefully inefficient. Now comes a Class B amp, that performs like a Class A amp, yet with three-times better efficiency. There were other subtle distortion-causing mechanisms that Randy’s new circuit also either reduced or eliminated entirely.
Sadly, Randy never fully completed this design and no one has ever heard it in action. In Randy’s laboratory, this breakthrough amplifier however, was setting a new benchmark in audio performance.
Fortunately, Randy emailed me the schematic before he passed on. I cannot tell whether the schematic I have is 100% tweaked, as I do not have Randy’s amazing understanding of analogue audio, but from what I can tell it looks exquisite. In fact, it looks like a work-of-art as what a master artist could only draw.
Few knew this, but Randy was a Trekkie (Star Trek fan) since the original Star Trek television show aired back in the late 60’s (1966 to be exact). He loved the original shows, and never really cared for the sequels. He would relax to re-runs of the old Star Trek series. Didn’t matter to Randy if he’d seen the episode for the hundredth-time…he was as captivated as if viewing for the first time.
Randy also had a deep religious faith, which helped console him through his many hardships. A truly multi-facetted individual, with whom could relate to almost everyone on one subject or another.
Randy was also an accomplished banjo player. His love of audio extended to the creation of music as well as the electrical reproduction of it. This allowed Randy to lend a critical ear to the performance of his audio gear. Randy gave a huge gift to the audio community. He will be remembered, admired and loved. Godspeed to your new shores my friend.
Russ
ZUS Audio Inc.
Russ, reading your tribute to Randy was a pleasure. Great to know that Randy had something to pass on even in his last days. I'd be really grateful if you could please P.M. me at cred@rediffmail.com or cred_audio@rediffmail.com. I am really interest in getting hold of a copy of Randy's unpublished book, "A Heresy by Fire".
Thanks,
Thanks,
Sorry Samuel, I look high and low for Randy's unpublished book "A Heresy of Fire" but could not find it. He did send it to me about 6 years ago. However I moved since then and might have misplaced it. I will keep looking.
Hi Russ,
Thanks so much for sharing this with us. I REALLY, REALLY wish I had had the opportunity to meet with Randy and chat with him on every subject that you have mentioned. I have also enjoyed very much reading his books, and am saddened that his breakthrough circuit on eliminating crossover distortion has not made it to the light of day.
Best,
Bob
Thanks so much for sharing this with us. I REALLY, REALLY wish I had had the opportunity to meet with Randy and chat with him on every subject that you have mentioned. I have also enjoyed very much reading his books, and am saddened that his breakthrough circuit on eliminating crossover distortion has not made it to the light of day.
Best,
Bob
I am currently building his AMP on a general PCB, it is just TOO good!
It doesn’t oscillate and I have learnt a lot through his book,
I will remember him but sad that I couldn’t thank him as I had planned once I complete it.
I have sacrificed my families’ time and spent 6 weekends on his book and assembling the circuits,
Even in office whenever I get time I read his book, I miss him real bad.
The faith he had on Christ will save him and God bless him and all who read his books.
It doesn’t oscillate and I have learnt a lot through his book,
I will remember him but sad that I couldn’t thank him as I had planned once I complete it.
I have sacrificed my families’ time and spent 6 weekends on his book and assembling the circuits,
Even in office whenever I get time I read his book, I miss him real bad.
The faith he had on Christ will save him and God bless him and all who read his books.
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Last edited:
Smathias,
Looking at your pictures I understand you used a mirror image topology with current mirror loads in the diff amp, also using cascoded VAS and two pole compensation.
There are many people here saying the VAS idling current is undefined. I share their issue. I tried to build that amp many times and it very seldom works. When it does today it will not tomorrow because of temperature change upsetting the VAS Iq again ... I started lately a thread about it...
Are you sure it works? How did you di it??
I would like to know...
By the way : Me too I loved the Slone Book ... very sad he passed away !
best regards
Olivier
Looking at your pictures I understand you used a mirror image topology with current mirror loads in the diff amp, also using cascoded VAS and two pole compensation.
There are many people here saying the VAS idling current is undefined. I share their issue. I tried to build that amp many times and it very seldom works. When it does today it will not tomorrow because of temperature change upsetting the VAS Iq again ... I started lately a thread about it...
Are you sure it works? How did you di it??
I would like to know...
By the way : Me too I loved the Slone Book ... very sad he passed away !
best regards
Olivier
What a great loss.
I have two of his books, though I am a big tube amp fan and he sort of dismissed tubes altogether on his high power amp project book, I understand exactly what he meant, and being a guitar amp guy myself(distortion welcome) I cannot blame him.
Some of the great minds in audio have left us too soon. Since 2006 the world has lost Ted Weber, Ken Fischer(Trainwreck) and Mr. Slone. Music amplified their souls to a new, higher, existence for sure. And they left us much to learn and to work upon.
RIP Mr. Slone
I have two of his books, though I am a big tube amp fan and he sort of dismissed tubes altogether on his high power amp project book, I understand exactly what he meant, and being a guitar amp guy myself(distortion welcome) I cannot blame him.
Some of the great minds in audio have left us too soon. Since 2006 the world has lost Ted Weber, Ken Fischer(Trainwreck) and Mr. Slone. Music amplified their souls to a new, higher, existence for sure. And they left us much to learn and to work upon.
RIP Mr. Slone
Hi Oliver73,
Yes it works perfectly fine and currently spent so many hours on fine tuning it.
I have assembled Slone's circuit of Figure11.12 on a general PCB but the BIAS/Vb multiplier was not stable. Though it worked fine but when i tried to adjust the voltage to 2.88V across Q19 it was not stable and once overshot and damaged my out and driver stage.
So to solve this problem all i did was to removed Q11 & Q12 and modified the circuit around Q13 & Q18 and it is PERFECT and very stable! I have Q19 on OP heat sink along with trim pot. I am using output Triples with feed forward circuit so the negative feedback has different values. It is stable with no oscillation and I can share video/photos what I have done so far, I am using MPSA42/92, TIP41/42 and MJ15003/4
I would say Slone’s topology is superb!
It turns on and off softly and no thumps at all, it sounds good to my ears better than Blameless.
Regards,
Santha Mathias
Yes it works perfectly fine and currently spent so many hours on fine tuning it.
I have assembled Slone's circuit of Figure11.12 on a general PCB but the BIAS/Vb multiplier was not stable. Though it worked fine but when i tried to adjust the voltage to 2.88V across Q19 it was not stable and once overshot and damaged my out and driver stage.
So to solve this problem all i did was to removed Q11 & Q12 and modified the circuit around Q13 & Q18 and it is PERFECT and very stable! I have Q19 on OP heat sink along with trim pot. I am using output Triples with feed forward circuit so the negative feedback has different values. It is stable with no oscillation and I can share video/photos what I have done so far, I am using MPSA42/92, TIP41/42 and MJ15003/4
I would say Slone’s topology is superb!
It turns on and off softly and no thumps at all, it sounds good to my ears better than Blameless.
Regards,
Santha Mathias
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