Revevealing Slone L-MOS 6.21 (OptiMOS) secrets Revevealing Slone L-MOS 6.21 (OptiMOS) secrets - diyAudio
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Revevealing Slone L-MOS 6.21 (OptiMOS) secrets
Revevealing Slone L-MOS 6.21 (OptiMOS) secrets
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Old 18th September 2013, 02:32 PM   #1
overpower is offline overpower
diyAudio Member
Join Date: Sep 2010
Default Revevealing Slone L-MOS 6.21 (OptiMOS) secrets

I've researched this forum a few years gained notoriety for G Randy Slone L - MOSFET amplifiers , and a few years ago, I have successfully done a few of the author circuits . Now, after a lot of researched I decided to experiment The Audiophile Project Sourcebook pages 172 to 182 described circuit Figure 6.21 , I've come across this in the name OptiMOS - but in this name of the book on these pages , however, is not to be noticing . Do you still have it just the OptiMOS assisted by some praise , some light up , many claim to have built but I have not even seen the pictures of this particular circuit Fig. 6.21 .
So, I made it , I actually finished and there are several drawbacks - it does not work that way , as I have previously worked from the prototype phase Slone diagrams .
I am also aware of the topics

Unstable VAS current in amp from Slone book

Complementary input stages with current mirrors

that reflect the author's unstable circuits but as far as the eye has been stated that the solution to 6.21 is perfectly capable of working . I dare to doubt this .
The problem I have is to be semiconductors V5 and V6 , they heat up circuit greatly energized for a few seconds , without Output L-MOS semiconductor output DC voltage is 650mV . In addition to tend to destroyed as R4 , R20 and R22 . V13 to V16 remain alive . It was observed that small transistors V1 to V12 and V17 , V18 nor destroyed but every attempt I have replaced all of them and also checked the diodes , all the parts are new , have been selected passive components 0.1 % accuracy . Is it still just the layout of the problems of the source? I will also still haunted by OptiMOS - which of these circuit is it really so? I have an Slone The Audiophile Project Sourcebook , as well as the High - Power Audio Amplifier Construction Manual , latest is 11.8 and 11.9 is 100 % working and very foolproof (I'm with them conducted several tests and still have not been able to kill any semiconductors ), it seems that the circuit is insecure 11.14 but now this list can be added in a newer book described a circuit 6.21 - legendary OptiMOS solution?

I will add a picture and my drawing , it seems that the drawing goes against "something" then it can be removed .

Is there anyone here who dares to suggest something based on this information , any questions that the scheme is expected - I hope to get the help of the answers to my questions. Or is there only mistake with the signal gnd?
Attached Images
File Type: jpg OptiMOS initial proto.jpg (370.2 KB, 326 views)
Attached Files
File Type: pdf OptiMOS silktop1.pdf (26.5 KB, 118 views)
File Type: pdf OptiMOS fig6 21.pdf (67.2 KB, 145 views)
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Old 18th September 2013, 03:18 PM   #2
RSK is offline RSK  Malaysia
diyAudio Member
Join Date: Nov 2004
Location: K.L.
Hi, Have you seen this site? Plamen Todorov's DIY Blog - A solid-state tale. My favourite amp.
Probably he could advice on his experiance. Looks like he made it.

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Old 18th September 2013, 03:37 PM   #3
Ian Finch is offline Ian Finch  Australia
diyAudio Member
Join Date: Apr 2010
Location: Coffs Harbour
Some time ago, Bob Cordell was hunting details of the OPTIMOS designs (there were other models), for his book, I understood, but some OPTIMOS versions are copyright to the company, ZUS Audio, to whom Randy sold his company, Seal Electronics back some years before his passing.
ZUS marketed kits, and even finished amps and published papers setting out the benefits etc. The site however, is currently down for 'restructuring'. Perhaps someone has information from ZUS that refers to amplifiers that do work as guaranteed, rather than something that may that not have been marketed or was doubtful from the outset.
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Old 22nd September 2013, 04:47 PM   #4
overpower is offline overpower
diyAudio Member
Join Date: Sep 2010
I myself have made a mistake - in my PCB and component layout drawings have been interchanged. I might say that this amp sounds interesting. Mostly listened to Dimmu Borgir and Xandria music, and it is interesting to amplifier sound at first glance would say that the "cold" or be the right word rather a transparent.
In any case version 6.21 OptiMOS is quite a high-potential, it seems to me. Dare to recommend this amp
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