New Design, SE 6005 Directly Coupled Audio Amplifier

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drlowmu

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PROGRESS REPORT .................... 10-12-2021






023 (2) edit3.jpg


The 13 ventilation holes on the right side ( above ) , I added carefully by hand this week, as an afterthought to enhance long term cooling and reliability. Besides the added ventilation holes we see, the entire Main Chassis surface area acts to cool the internal components when using chassis - mounted ARCOL HS 50 Watt-rated resistors.


029 (2) edit.jpg


034 (2) edit.jpg



This above is the first ( of two ) chassis . It is finished as far as being ready to powder coat, Midnight Blue Wrinkle, with a Pearl glow.

What you see is the prototype, that I keep for myself. It has 23 " non used, non wanted " small holes in it, from changing parts positions to come across the " best " layout within my capability. The second unit ( now 90 percent prepared for Powder Coating ) is a bit " cleaner" looking - with 23 less non-essential holes . There will be an attractive and strong six inch handle at the very top-front of the chassis, and a matching four inch handle at the left side-top rear.

The bottom cover, held onto the Main Chassis by six 8-32 brass bolts, will have multiple brass washers, between the bottom cover and the Main Chassis. These brass washers will have varying O.D.s or outer diameters, such that they form a pyramid shape when secured. These six pyramids, and four soft "EAR " brand made-for-audio feet, form a " Isolation Platform " of the 14 gauge steel bottom cover, between the Main Chassis and the amp's resting surface. The pyramids allow for some all-around-the -bottom ventilation, and provide a benefit S.Q.-wise, and from vibration control, that the EAR feet used alone will not produce. This idea is copied directly from Serious Stereo's wonderful SET amplifiers, by me. I only build amps in a steel chassis, not wood, for fire-safety reasons, plus 14 gauge steel sounds good VS aluminum IMHO.



.................................. SNIP ISOLATION Platform.jpg



Both chassis should be ready for the Powder Coating shop, by the end of this week.

Thank you for looking.

Jeff
 
Last edited:

drlowmu

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10-22-2021 .............................................. Photo Update

First two chassis just were returned from Powder Coaters. This conservative color is called " Midnight Blue Wrinkle" and it has a bit of pearl in it.



View attachment 63412 snip 2.JPG snip 3.JPG snip 4.JPG snip 5.JPG


On Sunday, 10-24-21, twelve tube sockets got satisfactorily installed into both chassis. Final assembly is progressing now.

Jeff
 
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drlowmu

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11-04-2021 ............................................. Mini PHOTO PROGRESS REPORT

Today, a dual ON-OFF AC switch system was installed. The first switch turns on the amp, and the second switch shorts-out the safety fuse, so the amp can pull maximum power from the Wall, when playing back music.

The second switch is called " an ATTENDED LISTENING " switch. It is illegal in a typical commercially manufactured product, but all my builds employ this to obtain better ( audibly better ) performance. This is especially noticeable with the type of Power Supplies ( Low in DCR, six Ohm chokes, etc. ) we find in my designs. The end-user gets to determine to employ, or not to emply the second switch, as the amp plays music either way.

In the last three years, we have found that separate multiple power transformers ( For B+, and separate for Filaments ) can give an audible performance edge. Importantly, we have also discovered that the AC phase of all the secondaries powering the circuit, MUST ALL be in phase-alignment with each other, to obtain the best sonic result.

The simple Keystone - manufactured terminal strip pictured below will provide adequate multiple attachment points ( NOT available on a tiny single FUSE's terminal ) , to allow doing an in-phase alignment of this amplifier's various secondary windings.



008 EDIT 3.jpg

Below are the two A-C switches, the Fuse Assembly, and the Multiple AC attachment points to optimize phase relationships of the Power Transformers. Such steps are done because of the desire to optimize one's listening experience on music playback. It is the ONLY justification.



17 EDIT 3.jpg


' Am building two amps at once, and tomorrow this gets done to the second stereo amplifier, plus more !!

Notice above how I have prepped the vintage NOS Amphenol Octal Rectifier tube sockets? They no longer have eight PINS sticking out. It is nicer to only have the four pins per socket, required for the 5U4GBs. I prefer the immediate instantaneous response of directly heated tube rectifiers.

Thank you - for looking.

Jeff

See how both sections of the AC switches are parallel wired ?

Also, for the first time ( for me ), the switch contacts on these AC switches are silver. Thanks to Scott in Texas !!
 
Last edited:

drlowmu

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11-07-2021........... Mini Photo Report

Beginnings of the Power Supply, ...........pre wiring. Little spare room.

054 top aok edited.jpg 056 ok.jpg 058 w L2 aok.jpg 059 aok.jpg


......Much more work to do. C1 and L2 are placed but not mounted. Extra Keystone #817 terminal strips have been added with decent ( high up ) access, to allow for easier Phase Alignment of AC transformer feeds......to enable a proper uniform polarity.

Imagine 1,500 Ampere ( instantaneous ) GTO capacitors, uniquely combined with two 6 Ohm Filter Chokes ....2021's
favorite power supply configuration.

Thank you again - for looking, following along.

Jeff
 
Last edited:

IndianEars

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11-07-2021........... Mini Photo Report

Beginnings of the Power Supply, ...........pre wiring. Little spare room.

View attachment 63951 View attachment 63952 View attachment 63953 View attachment 63954


......Much more work to do. C1 and L2 are placed but not mounted. Extra Keystone #817 terminal strips have been added with decent ( high up ) access, to allow for easier Phase Alignment of AC transformer feeds......to enable a proper uniform polarity.

Imagine 1,500 Ampere ( instantaneous ) GTO capacitors, uniquely combined with two 6 Ohm Filter Chokes ....2021's
favorite power supply configuration.

Thank you again - for looking, following along.

Jeff
Superb Pics!

Thanks
 

drlowmu

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11-14-2021 .................. Minor Progress Report

Slow, but positive progress, did almost everything two times, to get it modestly acceptable .....................C1 ( 30 uF WIMA DC Link ) and L2 ( 6 Ohm Hammond 159ZA ) not yet installed,...... both go in this picture's space.

006.JPG


009.JPG

011 edited 2.jpg



Thank you for looking. Two R-Core ( Softone RW-20 ) output transformers got mounted on the chassis' top-side this past week. Top-side looks very cool to me. Need to take photos of that.

Jeff
 
Last edited:

drlowmu

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Today - a partial discussion of capacitors and applying of same .

Warning :

( All that follows is in my own experience, in my own opinion, my own experience, and in my own belief system : )

A basic truth is that in audio, there is not a single capacitor that exists, that plays all ranges of the music, at their fullest fidelity. Not a one, no matter what the cost or size !!

Generally speaking a large microfarad cap plays the low end well, and vice versa for a small microfarad cap being able to intrinsically play the high end well. This relationship of cap uF and frequency has been known for decades, but sadly, very little has been done in audio, so as to OPTIMIZE a capacitor in a circuit, so that the cap plays well at ALL audio frequencies.

Only a handful of Manufacturers consistently practice combining multiple capacitors to obtain a wide playback response. Out of that handful, I am only aware of one, who seems to do it fabulously well, but I would hope this is not the sole proponent and instance.

Most ( 90% plus) of commercial audio equipment is designed to give the listener a decent swath of the midrange's music information. It is cheap and easy to do this, with a single ( musically deficient ) capacitor in a circuit's " capacitor" position. Conversely, it takes LOTS of money, and a talent in design, to develop a pre amplifier or amplifier that plays back music convincingly. Manufacturers would promptly go broke, providing such a level of playback.

What are the audio frequencies ???

Easy...same as the frequencies of live unamplified music. Music is wide band, and audio playback equipment should be, IF it is to mimic music.

Important Note: One does NOT need to have stellar hearing, to appreciate the music content in the highest frequencies. What is " beyond" our measured high frequency hearing, filters down, into the midrange, where people with compromised overall hearing, will readily appreciate the " above - 20KhZ " information, and say " thank you " for providing it in your audio equipment. Look up the word " resultants ".

AS a DIYer, one can apply whatever they want to have in their circuits, for any capacitor position !!! Assuming the DIYer can afford the parts cost, their motive is purely music enjoyment. Turning a profit on a part's cost, is not in the equation.

OK, let us " GET TO IT !!! "

The simplest answer is to combine multiple capacitors of high quality ( film types ) and of differing smaller values, into a circuit's single capacitor position. That makes sense, but you HAVE to do so - properly. This approach ASSUMES the builder has certain capabilities, which most do not have, unfortunately.

FIRST, it assumes the builder knows what precise uf ( microfarad ) value capacitor plays in each music range. Very very few audiophiles know !!!

SECOND, it assumes the builder has a audio system sensitive enough, good enough overall, to reveal where there exists playback problems.

THIRD, it assumes that the builder has the experienced hearing to quickly determine where a frequency range is missing in playback, or over-emphasized in playback. ( Where adjustments are needed. )

FOURTH, it assumes the builder knows what brands, types and values of film caps to add to a multiple bunch.

FIFTH, it assumes the builder has sufficient financial capability, to purchase the best caps for the job . This factor sadly, often looms largest, to hinder one's genuine build progress and education.

WHAT HAPPENS :

Someone " tries" multiple film bypassing, but ONLY by adding one cap. Yes, that region which the newly-added cap should play, may be better, but now, there are discontinuities, suck-outs, holes, VS hearing one cap alone !! At that point, they may "give up " or at the most, they may try two added caps. In all likely hood, possibly or probably one or both of the added caps are now the wrong uF values needed !! So, the ill prepared audiophile " gives up " on multiple film cap bypassing. Does that describe you ??? I did this, very early on.

Several decades ago, there was a favorite article of mine presented in I think USA's " Sound Practices " magazine. It covered a two stage DIY direct coupled SET amplifier build, by a couple of Italian DIYers, Marzio and Jelasi. It is on-line today . See it easily by clicking on the following URL :





What I want to bring to everyone's attention is their use of multiple film cap bypassing, of the most basic type, presented in writing, way back then. Notice in their posted parts list, out of seven cap positions in a mono amp, six cap positions are specified to be of three differing values. A main cap, and two specific value, constantly prescribed values .

Read the article.

We can do better than that circuit in 2021 BTW !! Notice the Italians' C2 through C7 are all " Triplet Bundles ". Differing uF MAIN caps as needed, each combined with a 0.22uF and a 0.022 uF film capacitor as a bypass !!!! Six out of seven cap positions, fully bypassed !!!

Hooray for the DIYers from Italy to divulge this information.

For your information, 0.22uF is probably the one best uF value to enhance the middle mid-range of music frequencies. Also, 0.022uF is likewise the best uF value in a SINGLE cap, to enhance the upper most frequencies, music's top-end.

How come it is three or maybe four decades later, where this finally gets pointed-out to interested-in-audio readers. ???

OK, BACK to 2021, this 6005 build.

1) For less chance of gaps, ( and better overall musical expression ) this thread's earlier-described" Modules " have not two or three caps in a bundle, but more like five minimum, starting with a film cap value optimizing the mid-bass.

2) Film caps available in 2021, such as WIMA caps, are lower in ESR and higher in performance, than Marzio's EARLY caps used in his filter chain. WIMAs just need some minor help, also possibly to offset wiring losses. So, for caps located in the 6005 amp's first three filtering stages ( C1, C2, C3, / 30uF, 80uF, 50uF ) we only need to address the music range where Marzio and Jelasi ( and others today ) might use a 0.022 uF cap.

3) But we wanted a bit more than what a single high frequency cap provides. In lieu of a single 0.022uF, we employ a single 0.033uF bypass AND a single 0.01uF bypass, ( to cover the highest of highs ) well enough. This combo of 0.033uF and 0.01 uF, ( assuming you select good caps ), will out-play musically a single 0.022uF cap.

We do not allow caps bodies to closely touch each other, so as to minimize field interactions. Picture's worth a 1,000 words.



C1 bypassing with an unshown 5 uF GTO :

009 (2)  edited C1.jpg

013 (2) c1 Number 2 edited.jpg

015 (2)  C1 number 3 edited.jpg

C2 with a 5 uF GTO :

002 (2) C2 number 1 edited 3.jpg

AND FINALLY :" C3, .................no GTO, GTOs just go to OUTPUT stage duty :

019 (2) C3 number 2 edited.jpg


Thanks again for looking. This multiple bypassing above was done on Sunday 11-14-21.

Jeff
 
Last edited:

Hari Iyer

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I have used bypass capacitors in my monoblock but have used them hapazardly for values not considering the frequency / impedance curve. TBH I am unable to decode sound quality attributes using different values and hence gave up due to budget and time constraints for film capacitor purchases. Maybe one day I would start this activity all over again as this is so much fun.

Thanks for your insights Jeff. Appreciated.
 

IndianEars

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Messages
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Today - a partial discussion of capacitors and applying of same .

Warning :

( All that follows is in my own experience, in my own opinion, my own experience, and in my own belief system : )

A basic truth is that in audio, there is not a single capacitor that exists, that plays all ranges of the music, at their fullest fidelity. Not a one, no matter what the cost or size !!

Generally speaking a large microfarad cap plays the low end well, and vice versa for a small microfarad cap being able to intrinsically play the high end well. This relationship of cap uF and frequency has been known for decades, but sadly, very little has been done in audio, so as to OPTIMIZE a capacitor in a circuit, so that the cap plays well at ALL audio frequencies.

Only a handful of Manufacturers consistently practice combining multiple capacitors to obtain a wide playback response. Out of that handful, I am only aware of one, who seems to do it fabulously well, but I would hope this is not the sole proponent and instance.

Most ( 90% plus) of commercial audio equipment is designed to give the listener a decent swath of the midrange's music information. It is cheap and easy to do this, with a single ( musically deficient ) capacitor in a circuit's " capacitor" position. Conversely, it takes LOTS of money, and a talent in design, to develop a pre amplifier or amplifier that plays back music convincingly. Manufacturers would promptly go broke, providing such a level of playback.

What are the audio frequencies ???

Easy...same as the frequencies of live unamplified music. Music is wide band, and audio playback equipment should be, IF it is to mimic music.

Important Note: One does NOT need to have stellar hearing, to appreciate the music content in the highest frequencies. What is " beyond" our measured high frequency hearing, filters down, into the midrange, where people with compromised overall hearing, will readily appreciate the " above - 20KhZ " information, and say " thank you " for providing it in your audio equipment. Look up the word " resultants ".

AS a DIYer, one can apply whatever they want to have in their circuits, for any capacitor position !!! Assuming the DIYer can afford the parts cost, their motive is purely music enjoyment. Turning a profit on a part's cost, is not in the equation.

OK, let us " GET TO IT !!! "

The simplest answer is to combine multiple capacitors of high quality ( film types ) and of differing smaller values, into a circuit's single capacitor position. That makes sense, but you HAVE to do so - properly. This approach ASSUMES the builder has certain capabilities, which most do not have, unfortunately.

FIRST, it assumes the builder knows what precise uf ( microfarad ) value capacitor plays in each music range. Very very few audiophiles know !!!

SECOND, it assumes the builder has a audio system sensitive enough, good enough overall, to reveal where there exists playback problems.

THIRD, it assumes that the builder has the experienced hearing to quickly determine where a frequency range is missing in playback, or over-emphasized in playback. ( Where adjustments are needed. )

FOURTH, it assumes the builder knows what brands, types and values of film caps to add to a multiple bunch.

FIFTH, it assumes the builder has sufficient financial capability, to purchase the best caps for the job . This factor sadly, often looms largest, to hinder one's genuine build progress and education.

WHAT HAPPENS :

Someone " tries" multiple film bypassing, but ONLY by adding one cap. Yes, that region which the newly-added cap should play, may be better, but now, there are discontinuities, suck-outs, holes, VS hearing one cap alone !! At that point, they may "give up " or at the most, they may try two added caps. In all likely hood, possibly or probably one or both of the added caps are now the wrong uF values needed !! So, the ill prepared audiophile " gives up " on multiple film cap bypassing. Does that describe you ??? I did this, very early on.

Several decades ago, there was a favorite article of mine presented in I think USA's " Sound Practices " magazine. It covered a two stage DIY direct coupled SET amplifier build, by a couple of Italian DIYers, Marzio and Jelasi. It is on-line today . See it easily by clicking on the following URL :





What I want to bring to everyone's attention is their use of multiple film cap bypassing, of the most basic type, presented in writing, way back then. Notice in their posted parts list, out of seven cap positions in a mono amp, six cap positions are specified to be of three differing values. A main cap, and two specific value, constantly prescribed values .

Read the article.

We can do better than that circuit in 2021 BTW !! Notice the Italians' C2 through C7 are all " Triplet Bundles ". Differing uF MAIN caps as needed, each combined with a 0.22uF and a 0.022 uF film capacitor as a bypass !!!! Six out of seven cap positions, fully bypassed !!!

Hooray for the DIYers from Italy to divulge this information.

For your information, 0.22uF is probably the one best uF value to enhance the middle mid-range of music frequencies. Also, 0.022uF is likewise the best uF value in a SINGLE cap, to enhance the upper most frequencies, music's top-end.

How come it is three or maybe four decades later, where this finally gets pointed-out to interested-in-audio readers. ???

OK, BACK to 2021, this 6005 build.

1) For less chance of gaps, ( and better overall musical expression ) this thread's earlier-described" Modules " have not two or three caps in a bundle, but more like five minimum, starting with a film cap value optimizing the mid-bass.

2) Film caps available in 2021, such as WIMA caps, are lower in ESR and higher in performance, than Marzio's EARLY caps used in his filter chain. WIMAs just need some minor help, also possibly to offset wiring losses. So, for caps located in the 6005 amp's first three filtering stages ( C1, C2, C3, / 30uF, 80uF, 50uF ) we only need to address the music range where Marzio and Jelasi ( and others today ) might use a 0.022 uF cap.

3) But we wanted a bit more than what a single high frequency cap provides. In lieu of a single 0.022uF, we employ a single 0.033uF bypass AND a single 0.01uF bypass, ( to cover the highest of highs ) well enough. This combo of 0.033uF and 0.01 uF, ( assuming you select good caps ), will out-play musically a single 0.022uF cap.

We do not allow caps bodies to closely touch each other, so as to minimize field interactions. Picture's worth a 1,000 words.



C1 bypassing with an unshown 5 uF GTO :

View attachment 64268

View attachment 64269

View attachment 64270

C2 with a 5 uF GTO :

View attachment 64271

AND FINALLY :" C3, .................no GTO, GTOs just go to OUTPUT stage duty :

View attachment 64273


Thanks again for looking. This multiple bypassing above was done on Sunday 11-14-21.

Jeff
Thanks! drlowmu for a detailed, informative and richly illustrated post.

It has generally accepted practice, for several years, to bypass Electrolytic Capacitors by 1% of the Original Value and then again by a 1% OF THE 1%. (The smaller value capacitors are chosen for good audio properties in their frequency range over which they operate in the Circuit.)

As an Example:

a 1 mfd Cap will have in parallel
a 0.01 mfd (ie 10 nF) + in parallel ------ ie 1% of 1 mfd
a 0.1 nF ie 100 pF ------ ie 1% of 10nF

Most Electrolytic Caps have zero capacitance above 100 KHz and are actually inductors at 100 KHz and higher frequencies..... Not surprising when you consider the substantial length of electrolytic film that is tightly rolled to create the capacitor..... and then there is ESR as you have also mentioned.

Very Nice post .... :)
 

drlowmu

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11-19-2021 ....................................... Mini Report .............. " An inch of BAD wire "


My first Audio mentor, the late Mr. Robert W. Fulton, used to say " An inch of BAD wire can ruin the musical experience".


Of course, I believe him to be 100% correct.

Today 11-19-21, I wire modified the leads to a Hammond 6 Ohm DCR 1 Ampere rated B+ choke. ( 159ZA, a pair in L1/C1/L2/C2 series is a favorite .)

Replaced the stock thin 22 AWG black wiring, to two 14 AWG Mil Spec yellow wire leads, copper stranded and silver plated.

While we have today's unit " exposed ", and half way done, a few photos were taken, so that other friends who DIY might observe.

You may critique the soldering, and it will not bother me. Such a big solder " blob ". 'Used a Weller D-550 gun, 325 Watt setting. Honestly, I would rather have poor soldering and good wiring, than vice versa.


005.JPG
006.JPG

Thanks for viewing.

Jeff
 
Last edited:

Dev.R

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Nov 28, 2016
Messages
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Today - a partial discussion of capacitors and applying of same .

Warning :

( All that follows is in my own experience, in my own opinion, my own experience, and in my own belief system : )

A basic truth is that in audio, there is not a single capacitor that exists, that plays all ranges of the music, at their fullest fidelity. Not a one, no matter what the cost or size !!

Generally speaking a large microfarad cap plays the low end well, and vice versa for a small microfarad cap being able to intrinsically play the high end well. This relationship of cap uF and frequency has been known for decades, but sadly, very little has been done in audio, so as to OPTIMIZE a capacitor in a circuit, so that the cap plays well at ALL audio frequencies.

Only a handful of Manufacturers consistently practice combining multiple capacitors to obtain a wide playback response. Out of that handful, I am only aware of one, who seems to do it fabulously well, but I would hope this is not the sole proponent and instance.

Most ( 90% plus) of commercial audio equipment is designed to give the listener a decent swath of the midrange's music information. It is cheap and easy to do this, with a single ( musically deficient ) capacitor in a circuit's " capacitor" position. Conversely, it takes LOTS of money, and a talent in design, to develop a pre amplifier or amplifier that plays back music convincingly. Manufacturers would promptly go broke, providing such a level of playback.

What are the audio frequencies ???

Easy...same as the frequencies of live unamplified music. Music is wide band, and audio playback equipment should be, IF it is to mimic music.

Important Note: One does NOT need to have stellar hearing, to appreciate the music content in the highest frequencies. What is " beyond" our measured high frequency hearing, filters down, into the midrange, where people with compromised overall hearing, will readily appreciate the " above - 20KhZ " information, and say " thank you " for providing it in your audio equipment. Look up the word " resultants ".

AS a DIYer, one can apply whatever they want to have in their circuits, for any capacitor position !!! Assuming the DIYer can afford the parts cost, their motive is purely music enjoyment. Turning a profit on a part's cost, is not in the equation.

OK, let us " GET TO IT !!! "

The simplest answer is to combine multiple capacitors of high quality ( film types ) and of differing smaller values, into a circuit's single capacitor position. That makes sense, but you HAVE to do so - properly. This approach ASSUMES the builder has certain capabilities, which most do not have, unfortunately.

FIRST, it assumes the builder knows what precise uf ( microfarad ) value capacitor plays in each music range. Very very few audiophiles know !!!

SECOND, it assumes the builder has a audio system sensitive enough, good enough overall, to reveal where there exists playback problems.

THIRD, it assumes that the builder has the experienced hearing to quickly determine where a frequency range is missing in playback, or over-emphasized in playback. ( Where adjustments are needed. )

FOURTH, it assumes the builder knows what brands, types and values of film caps to add to a multiple bunch.

FIFTH, it assumes the builder has sufficient financial capability, to purchase the best caps for the job . This factor sadly, often looms largest, to hinder one's genuine build progress and education.

WHAT HAPPENS :

Someone " tries" multiple film bypassing, but ONLY by adding one cap. Yes, that region which the newly-added cap should play, may be better, but now, there are discontinuities, suck-outs, holes, VS hearing one cap alone !! At that point, they may "give up " or at the most, they may try two added caps. In all likely hood, possibly or probably one or both of the added caps are now the wrong uF values needed !! So, the ill prepared audiophile " gives up " on multiple film cap bypassing. Does that describe you ??? I did this, very early on.

Several decades ago, there was a favorite article of mine presented in I think USA's " Sound Practices " magazine. It covered a two stage DIY direct coupled SET amplifier build, by a couple of Italian DIYers, Marzio and Jelasi. It is on-line today . See it easily by clicking on the following URL :





What I want to bring to everyone's attention is their use of multiple film cap bypassing, of the most basic type, presented in writing, way back then. Notice in their posted parts list, out of seven cap positions in a mono amp, six cap positions are specified to be of three differing values. A main cap, and two specific value, constantly prescribed values .

Read the article.

We can do better than that circuit in 2021 BTW !! Notice the Italians' C2 through C7 are all " Triplet Bundles ". Differing uF MAIN caps as needed, each combined with a 0.22uF and a 0.022 uF film capacitor as a bypass !!!! Six out of seven cap positions, fully bypassed !!!

Hooray for the DIYers from Italy to divulge this information.

For your information, 0.22uF is probably the one best uF value to enhance the middle mid-range of music frequencies. Also, 0.022uF is likewise the best uF value in a SINGLE cap, to enhance the upper most frequencies, music's top-end.

How come it is three or maybe four decades later, where this finally gets pointed-out to interested-in-audio readers. ???

OK, BACK to 2021, this 6005 build.

1) For less chance of gaps, ( and better overall musical expression ) this thread's earlier-described" Modules " have not two or three caps in a bundle, but more like five minimum, starting with a film cap value optimizing the mid-bass.

2) Film caps available in 2021, such as WIMA caps, are lower in ESR and higher in performance, than Marzio's EARLY caps used in his filter chain. WIMAs just need some minor help, also possibly to offset wiring losses. So, for caps located in the 6005 amp's first three filtering stages ( C1, C2, C3, / 30uF, 80uF, 50uF ) we only need to address the music range where Marzio and Jelasi ( and others today ) might use a 0.022 uF cap.

3) But we wanted a bit more than what a single high frequency cap provides. In lieu of a single 0.022uF, we employ a single 0.033uF bypass AND a single 0.01uF bypass, ( to cover the highest of highs ) well enough. This combo of 0.033uF and 0.01 uF, ( assuming you select good caps ), will out-play musically a single 0.022uF cap.

We do not allow caps bodies to closely touch each other, so as to minimize field interactions. Picture's worth a 1,000 words.



C1 bypassing with an unshown 5 uF GTO :

View attachment 64268

View attachment 64269

View attachment 64270

C2 with a 5 uF GTO :

View attachment 64271

AND FINALLY :" C3, .................no GTO, GTOs just go to OUTPUT stage duty :

View attachment 64273


Thanks again for looking. This multiple bypassing above was done on Sunday 11-14-21.

Jeff
Very informative post Jeff, learning a lot from you. A big thanks and high regards.
Dev
 

drlowmu

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Messages
205
Points
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Location
Warrensburg, Missouri
Very informative post Jeff, learning a lot from you. A big thanks and high regards.
Dev


Thanks Dev,

In a conversation last night, my audio mentor ( for the last three decades ), tells me he has found a single 12 AWG m22759/11 will outperform my doubled up pair of 14 AWG m22759/11 wires. He has listened to both configurations, on his superb Serious Stereo sound system. MLTLs.

Looks like I will re-do this and the other choke, to single 12 AWG leads - today. Want to have best possible sonic result !!

You have P.M.

Jeff

setup 1 2020 SJNIPPED.jpg
 
Last edited:

Hari Iyer

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Messages
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Thanks Dev,

In a conversation last night, my audio mentor ( for the last three decades ), tells me he has found a single 12 AWG m22759/11 will outperform my doubled up pair of 14 AWG m22759/11 wires. He has listened to both configurations, on his superb Serious Stereo sound system. MLTLs.

Looks like I will re-do this and the other choke, to single 12 AWG leads - today. Want to have best possible sonic result !!

You have P.M.

Jeff

View attachment 64483
I am using a single 12 awg millspec wire for the chokes with superior dynamics.
 

drlowmu

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I am using a single 12 awg millspec wire for the chokes with superior dynamics.

OK Hari. ..... 11-21-2021 ............................. DOUBLE YELLOW 14 AWG -- to Single ORANGE 12 AWG

As suggested to Dev.R today, we ( un-modded and re-modded ) - changed both of those double 14 AWG yellow lead chokes, to single 12 AWG lead sexy looking ORANGE-colored wiring. This was for the second amp, the one destined for a nice client, and good use.

To re-cover the "cut-open" chokes we used one inch wide tape, used medically to hold dressings on a patient. The tape comes in paper, plastic and cloth with an adhesive backing. Today, we bought a roll of CLOTH and we like cloth tape the best - of those three tape choices. It looks very close to the stock covering. See both Hammond chokes,, now re-done, below :


001.JPG

And below again, a second ( amplifier ) view - with some parts notations for you.

I didn't have to do this re-mod. But in clear conscience, knowing where this 6005 DC amp is to be used, ( on Lowther Beauhorns ), and WHO is to use it, we really HAD to include - this small wire improvement.


002 EDITED.jpg

It is ideal. We have free hand on this build, and KNOW without asking, the client would be happy if we took one extra day to re-do this. Both chokes done " forever " as of now !!

Thanks everyone - for looking. We like the orange color, very " peppy " and upbeat.

Jeff
 
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drlowmu

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11-23-2021 ...................... Latest Build Idea .......................... Implemented

A 50,000 Ohm SHUNT resistor, across a B+ measuring 411 VDC, draws 8 milliamperes of current to ground. The power dissipated by this Shunt resistor is ( Ohms Law ) 411 VDC times 0.008 Amperes, or about 3.38 Watts, continuous.

We design for maximum reliability.

We use a ARCOL HS series 50 Watt resistor, because it is voltage rated at 1,250 VDC, well above 411 VDC in use, and it is a PULSE - designed resistor, which we know " sounds acceptable ".

The 50 Watt rated resistor depends upon a heat sink, to obtain it's maximum 50 Watt power rating. With no heat sink, the device can do up to 14 Watts, with an elevated operating temperature. We have conservatively added a " 10 Watt " rated heatsink to the bare resistor. The ARCOL HS 50 Watt resistor ( Ohm's Law ) operates a 3.38 Watts. Very conservative design and part use.

The question over the past two weeks was this : " How to mount the resistor, below the chassis, without making lots of unsightly chassis ( bolt ) holes. Also, how to place it where it would be ideally located - chassis space wise - relative to all the other power supply parts.

After two weeks of thought, here was what was " invented " yesterday, ...... finally !!



6 Edit 2 USE.jpg

And , another view, below:

009.JPG


This all fits with trying to efficiently build in three dimensions, below deck, not just two dimensions.

FYI, these parts were slightly modified Keystone "Board Brackets " and 4-40 by two inch sized stainless steel bolts. We sanded the anodizing off the back of the ARCOL HS and applied thermal paste to enable heat transfer to the " mini" 10 Watt add-on heat sink. That small heat sink was obtained from Michael Percy Audio..

Thank you for looking. Now, on - to more power supply wiring.


Jeff

yes ,............ " repositions " ....................is the right spelling.
 
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Hari Iyer

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The heat sink looks puny to me. Efficient heat transfer is key for performance. I still like the chassis mounting idea to distribute heat evenly.
 

drlowmu

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The heat sink looks puny to me. Efficient heat transfer is key for performance. I still like the chassis mounting idea to distribute heat evenly.

I agree with your comments, from what little you were shown. But there is more to this than what meets the eye when judging from those two photos alone !!

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

When you run out of attaching-to-the-chassis space, .............. we need to improvise free-air mounting.

That is what this is.

F
ree air mounting, in a limited space, in a stereo amplifier.

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

The ARCOL HS resistor with no heatsink at all ( see data sheet below ) is rated 14 Watts maximum, and can probably do 3.38 Watts continuous - in a less than ideal fashion. That ten watt rated add-on heatsink is OK in my opinion. Underside space for any add-on heat sink is limited.


Also, not shown in the posting and very important : the resistor is able to now be positioned purposefully and almost ideally, relative to the adjoining below-chassis power supply circuitry.

Many considerations Hari were taken into account, simultaneously, ............and they have been.


Jeff
 

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Hiten

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Nice build.
I am technically challenged with little experience but would it help if the heatsink are inverted as shown in the pic ? This way the air flow around the resistor would not be obstracted (Which would be dissipating maximum heat) and black heat sink fins would also get some air. Also shouldn't the star ground be cleaned off powder coating ? In my lm3886 build I cleaned off the paint with electric drill with bit going through and the chuck scrapping off the paint.
kindly see three pic. below.
Regards
 

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