Lesson #1 Video, Topic: Single Stage Preamp Design

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srb

Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #60 on: 21 Nov 2012, 03:08 am »
Pure silver is 108 or 8% better. ..... One could just make the copper 8% larger and get the same effect.

Thank you, very excellent point.
 
Steve

cheap-Jack

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Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #61 on: 21 Nov 2012, 03:21 pm »
Hi
Here is a table of conductivity that uses copper as a reference at 100. http://www.eddy-current.com/condres.htm

(1) Pure silver is 108 or 8% better. When silver oxidizes it is still a good conductor where copper is not.

(2) Copper oxide forms a rectifier.  However this is usually not a problem with good plated connectors.  Given that the resistance of most cables is almost nothing then 8% less than almost nothing is still almost nothing. One could just make the copper 8% larger and get the same effect.

(1) Yes, copper does oxides easily. But silver does not oxide that easily under atmospheric condition.
     Silver 'tarnishes' pretty quickly with sulphur chemicals, e.g. hydrogen sulphur, in polluated atmospheric
     air. In common language, copper oxides but silver tarnishes. We don't call silver oxides but call it
     tarnishes.

(2) Again, don't go by the book, please. 8% electrical conductivity alone seems no big deal.
     Pure copper can never touch the sound of pure silver even copper made 20% larger. I can bet.

     But with what I compared in depth the sonic difference before I jumped onto the pure silver wagon, 
     I think it could be the molecular structure difference btween these 2 metals. Correct me if I were wrong.
     But sonically silver sounds so much better always stand.

     I have been using 99.9999% pure copper for my audio. But when compard to 99.99% pure silver,
     it craps out. Silver sounds so silky, elegant & dynamic that pure copper just lacks.

     Even when cranked very high SPLs, the pure silver interconnects I DIYed built maintain the integrity of the music micro-structure when copper already craps out lossing the music minor inner details, & sounds even agitating.

     Otherwise why should I have gone the great pain of researching & then building pure silver interconnects & power cords which do NOT tarnish (with the special 'recepes' I developed). Very pure Ag costs a lot lot more than Cu, my friend.

May I ask you a silly question: have you even tried it out technically & sonically when you made such statement that 8% larger Cu will make the "same effects"??

FYI, the most expensive audio gear in the world is Audio Note Japan, IMO. Its handbuilt flagship power amp: "Ongaku" (it means music in Japanese), is tagged for USD180,000 a pair of tube monoblocks.
It is loaded with 'tons' of pure silver - silver wound choke, O/P & power irons, silver caps, silver interwiring
through-out. I was invited to have a full-audition of the total silver loaded Audio Note audio system in its
regional dealership studio only last Jan. WOW! Were I rich & famous or what to get this life-time chance.

 c-J

PS: are you still interested to carry on discussion of the "unconventional" design/build of my 1-tube 1-stage stereo phonostage?




     


Roger A. Modjeski

Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #62 on: 21 Nov 2012, 05:23 pm »
Hi
(1) Yes, copper does oxides easily. But silver does not oxide that easily under atmospheric condition.
     Silver 'tarnishes' pretty quickly with sulphur chemicals, e.g. hydrogen sulphur, in polluated atmospheric
     air. In common language, copper oxides but silver tarnishes. We don't call silver oxides but call it
     tarnishes.

(2) Again, don't go by the book, please. 8% electrical conductivity alone seems no big deal.
     Pure copper can never touch the sound of pure silver even copper made 20% larger. I can bet.

     But with what I compared in depth the sonic difference before I jumped onto the pure silver wagon, 
     I think it could be the molecular structure difference btween these 2 metals. Correct me if I were wrong.
     But sonically silver sounds so much better always stand.

     I have been using 99.9999% pure copper for my audio. But when compard to 99.99% pure silver,
     it craps out. Silver sounds so silky, elegant & dynamic that pure copper just lacks.

     Even when cranked very high SPLs, the pure silver interconnects I DIYed built maintain the integrity of the music micro-structure when copper already craps out lossing the music minor inner details, & sounds even agitating.

     Otherwise why should I have gone the great pain of researching & then building pure silver interconnects & power cords which do NOT tarnish (with the special 'recepes' I developed). Very pure Ag costs a lot lot more than Cu, my friend.

May I ask you a silly question: have you even tried it out technically & sonically when you made such statement that 8% larger Cu will make the "same effects"??

FYI, the most expensive audio gear in the world is Audio Note Japan, IMO. Its handbuilt flagship power amp: "Ongaku" (it means music in Japanese), is tagged for USD180,000 a pair of tube monoblocks.
It is loaded with 'tons' of pure silver - silver wound choke, O/P & power irons, silver caps, silver interwiring
through-out. I was invited to have a full-audition of the total silver loaded Audio Note audio system in its
regional dealership studio only last Jan. WOW! Were I rich & famous or what to get this life-time chance.

 c-J

PS: are you still interested to carry on discussion of the "unconventional" design/build of my 1-tube 1-stage stereo phonostage?




   

1. Read carefully: I was speaking of the resistance of copper vs silver, no other quality. Here is a brief note on "tarnish" http://en.wikipedia.org/wiki/Tarnish

2. I am in the industry (unlike yourself) and I am quite aware of the Ongaku, its price, its design, its fame. However its cost is rather out of the question for most people. How much the silver contributes is unknown, since we don't have one made with copper wire to compare.  I am very aware of the price of silver vs copper. I sold eight 100 ounce of it recently and I take all my scrap copper wire to the yard and get $1.50/pound for it.

It is well known that good ENGINEERING is a balance between cost and performance. Anyone can overdesign something, anyone can use the most expensive materials.

I have already stated the potential difficulties that the user may have in putting a single stage RIAA preamp in his system and pointed out their limitations. I am happy to have an open discussion on the matter, however this forum is intended to share information and Pontification does now sit well with its members as you can see. So far you have shared nothing about your RIAA preamp design other than the fact that you are in love with your own work.

p.s. I know the man who promoted the Ongaku amps and made them famous. He is a rather infamous character and the story I have heard is that he sold them to very wealthy clients who knew nothing about audio and just bought them because they were silver and expensive and pretty. It is not a bad amplifier but is it $180,000 good. Recent articles in Stereophile by Art Dudley and others have been pointing out the motivation behind expensive equipment is often for the "entertainment" of very wealthy individuals as an alternative to buying a winery or other expensive, flashy en-devour.

 

cheap-Jack

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Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #63 on: 21 Nov 2012, 06:36 pm »
Hi.

(1) 1. I was speaking of the resistance of copper vs silver, no other quality.

(2) It is well known that good ENGINEERING is a balance between cost and performance. Anyone can overdesign something, anyone can use the most expensive materials.

(3) I have already stated the potential difficulties that the user may have in putting a single stage RIAA preamp in his system and pointed out their limitations. I am happy to have an open discussion on the matter, however this forum is intended to share information and Pontification does now sit well with its members as you can see. So far you have shared nothing about your RIAA preamp design other than the fact that you are in love with your own work.

(4) It is not a bad amplifier but is it $180,000 good. Recent articles in Stereophile by Art Dudley and others have been pointing out the motivation behind expensive equipment is often for the "entertainment" of very wealthy individuals as an alternative to buying a winery or other expensive, flashy en-devour.

(1) Yes, you only showed electrical resistivity difference. But with yr statement of "same effect", many many AC readers out there will be given the incorrect idea that 8% bigger Cu = Ag which is NOT.

(2) Yes, that's the insight of quality engineering.

That's why I had to build my silver cables to save a fortune instead of buying from any cable vendors even if such pure silver cables were available in the marketplace. But there is none yet.

FYI, I am a DIY die-hard. The last thing I want to do in audio is to spend my hard-earned cash to finance any audio vendors.

(4) Please don't get me wrong. I am not promoting any mega-bucked commercial audio products here. I'd just want to confirm the fact that pure Ag is the BETTER way to go for quality audios as the Ongaku example. That's what I mean by "thinking out of the box".

(3) Let me cut the long story short:-

Yes, the tube is 50-year old Telefunken ECC83s I am using in my 1-stage phonostage. You guessed it right.

HV:- +440V (chip regulated)

Cathode bias: 2.3V - using no resistor bias which sounds only so so. I have used a much better topology sonically.

Surely no loop feedback type of RIAA equalization used in mult-stage phonostage designs.

Now I believe you already got some good idea of the design.

What do you think?

Surely it needs an active linestage to boost up the low O/P voltge to 2V or so to drive any power amps.

But as an audio 'purist', I prefer NOT to use any active linestage to screw up the sound quality. I tried to use it to drive my tube power amp direct & am very impressed by the neutral sound quality though the volume pot has to set up up.

But who should worry about the volume pot setting as long as the volume is adequate for quality music.

c-J 




G Georgopoulos

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Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #64 on: 21 Nov 2012, 11:54 pm »
Hi Roger,isn't a single stage enough for a preamp...Why use a multistage etc?...

kind regards  :)

George

cheap-Jack

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Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #65 on: 22 Nov 2012, 02:11 pm »
Hi.
Hi Roger,isn't a single stage enough for a preamp...Why use a multistage etc?...

kind regards  :)

George

Good question. I am expecting answers from whoever "thinking out of the box".

c-J

rbwalt

Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #66 on: 22 Nov 2012, 03:28 pm »
hey c-j not everyone is a diy person. so us poor souls must finance vendors , like roger and others.  when we do this we create jobs right down the line. of course you know this as one who has been what in the electronics industry for 30 yrs or so. buy the way i do not know what country you reside in but here in the US roger is probably in the top 3 of audio designers. you might want to talk to George cardas on the purity of copper and wire in general.

happy thanksgiving.

Roger A. Modjeski

Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #67 on: 24 Nov 2012, 01:41 am »
Hi Roger,isn't a single stage enough for a preamp...Why use a multistage etc?...

kind regards  :)

George

Yes a single stage is enough... and sometimes to much for a line amp. When CD is the main source or one has a high gain RIAA phono preamp more than 12 dB is too much. The traditional gain for a line amp is 20 dB. I recognized this problem in 1980 and made the RM-5 with internal DIP switches so the gain could be set with several choices between 0 and 30 dB which is the full gain of a 6922 tube. Other designers have chosen lower gain tubes like the 6SN7 and 12AU7 which have lower gains (12-16 dB) but these tubes are not known for low noise and low microphonics like the 6922, making this a poor choice as a designer but its good for my tube business as I can supply these tubes with low noise where other vendors can't.

I also have available a solution for the too high gain line stage which, besides making the volume control too sensitive also causes system noise that does not go down with the volume control. When a line amp has a lot of gain it usually has a lot of output noise which is then amplified by the power amp and may cause problems even at the listening position. I have made many listeners happy by providing an attenuator that goes between the preamp and power amp. Besides reducing noise, it also makes the volume control more useful putting it up into the higher ranges.

Of course, to me the best solution for too much gain is a passive preamp and for that I make "Pot in a Box" and active "Pot in a Box" for those who think a passive preamp lacks dynamics. For this (perceived lack of dynamics) I have no explanation. Whether the volume control "sees" a tube nearby or the first tube in the power amp there is no difference in my mind. Of course, the cable between has to be low capacitance. short and shielded. Perhaps driving the cable is the problem.

G Georgopoulos

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Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #68 on: 24 Nov 2012, 02:04 am »
Hi Roger, taking the output signal from the cathode resistor would be ideal, you could pass the signal through a tube and get the tube benefits, as for passive amplifiers (pot in a box) I have used them and work as predicted.

kind regards  :)

Roger A. Modjeski

Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #69 on: 24 Nov 2012, 08:14 pm »
Hi.
Yes, the tube is 50-year old Telefunken ECC83s I am using in my 1-stage phonostage. You guessed it right.

HV:- +440V (chip regulated)

Cathode bias: 2.3V - using no resistor bias which sounds only so so. I have used a much better topology sonically.

Surely no loop feedback type of RIAA equalization used in mult-stage phonostage designs.

Now I believe you already got some good idea of the design.

What do you think?

Surely it needs an active linestage to boost up the low O/P voltge to 2V or so to drive any power amps.

But as an audio 'purist', I prefer NOT to use any active linestage to screw up the sound quality. I tried to use it to drive my tube power amp direct & am very impressed by the neutral sound quality though the volume pot has to set up up.

But who should worry about the volume pot setting as long as the volume is adequate for quality music.

c-J

I think it would be nice to share more of what you are doing. This is a nice start. You might state how you have achieved the RIAA EQ, how accurate it is, how you deal with the variable loading that a passive volume control presents.

I don't understand your comment: "Cathode bias: 2.3V - using no resistor bias which sounds only so so. I have used a much better topology sonically."

Clio09

Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #70 on: 24 Nov 2012, 08:49 pm »
Of course, to me the best solution for too much gain is a passive preamp and for that I make "Pot in a Box" and active "Pot in a Box" for those who think a passive preamp lacks dynamics. For this (perceived lack of dynamics) I have no explanation. Whether the volume control "sees" a tube nearby or the first tube in the power amp there is no difference in my mind. Of course, the cable between has to be low capacitance. short and shielded. Perhaps driving the cable is the problem.

The last sentence of the quote is interesting. In addition to your amps I use an Atma-Sphere OTL. I use passive preamps with both, currently commercial LDR designs, but I have built an autoformer volume control and another using Jack Elliano's passive voltage attenuator circuit. The latter uses transformers to step up the voltage from the source which is then attenuated using a 10k pot. According to Jack this allows for more dynamics versus just feeding the signal straight to the pot.

Now Ralph Karsten feels that passive preamps are nice, but can never reproduce the bass frequencies as well as a properly designed active. As a huge proponent of passive preamps I respectfully disagree with his opinion. However, he does make one interesting point on what a well designed active preamp should accomplish. In his opinion it is to control the interconnect. This means not only the ability to drive it, but to control the artifacts. His designs being fully differential and supporting the 600 ohm standard, Ralph indicates one cannot hear any difference in cables inserted between his preamps and amps. I guess I am going to find out soon enough. Ralph and I came to somewhat of a compromise and he is making me a preamp that will primarily serve as a tape head preamp. The tape input will have an equalization circuit and gain, but the line stage itself will not have any gain and a tube buffered output.

Rclark

Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #71 on: 25 Nov 2012, 07:02 am »
I find your comments about passive being good enough (and that people are hearing (or imagining) things in terms of a lack of dynamics) interesting and personally relevent. I have a powered ldr combined with my Ncore fully analogue, non digital, class D amps and everything top to bottom is amazing, liquid, knock your socks off, blow your wig back, including bass, ripped, defined abs of bass. Sorry I have no tubes for relation to this conversation, but my amps rock, and so does my volume knob. My experience with strong voltage source - battery powered ldr knob with no gain - top spec amps is out of this world. And, I'm not talking about loudness... at all.
« Last Edit: 25 Nov 2012, 08:12 am by Rclark »

Roger A. Modjeski

Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #72 on: 25 Nov 2012, 08:38 pm »
I find your comments about passive being good enough (and that people are hearing (or imagining) things in terms of a lack of dynamics) interesting and personally relevent. I have a powered ldr combined with my Ncore fully analogue, non digital, class D amps and everything top to bottom is amazing, liquid, knock your socks off, blow your wig back, including bass, ripped, defined abs of bass. Sorry I have no tubes for relation to this conversation, but my amps rock, and so does my volume knob. My experience with strong voltage source - battery powered ldr knob with no gain - top spec amps is out of this world. And, I'm not talking about loudness... at all.

I would like to know more about your LDR (Light Dependent Resisistor) volume conrol such as the input/output impedance. I am also curious about how well the channels stay in balance over the range of attenuation. Do you have some links to read? Thanks..

Rclark

Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #73 on: 25 Nov 2012, 08:39 pm »
http://www.diyaudio.com/forums/vendors-bazaar/176847-warpspeed-optocoupler-volume-control.html

"The Warpspeed came about to address some of the shortcomings of current LDR volume controls. On the list are:

-the inability to adjust to complete silence
-on low/high volume level settings, power levels on the LEDs endanger/shorten/toast the life out of the optocouplers
-the need to improve the power delivery to the optocouplers
-the need to improve on quality of the volume adjustment pot
-the Lightspeed, simple as it is, still has a number of variables/design factors that affect performance

The Warpspeed solves the above and then some. Added bonus are:

-low volume levels are more engaging and equally enjoyable (ie. the music details are as much as when at moderate/loud levels)
-low volume listening is perfect in conjunction with NP's monotonic amps -decreasing distortion at lower audio levels (might explain above experience)
-wider range of volume level settings
-battery power means less ac power related artefacts on optocouplers
-precise power delivery and control at safe levels on optocouplers
-by design keeps optocouplers' power level ratio at/near equilibrium
-peace of mind at any volume level"


cheap-Jack

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Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #74 on: 26 Nov 2012, 03:18 pm »
Hi

 ...everything top to bottom is amazing, liquid, knock your socks off, blow your wig back, including bass, ripped, defined abs of bass. Sorry I have no tubes for relation to this conversation, but my amps rock, and so does my volume knob.

My experience with strong voltage source - battery powered ldr knob with no gain - top spec amps is out of this world. And, I'm not talking about loudness... at all.
.

I am glad to hear some positive comment from a passive 'preamp' user who also knows what is quality music - "I am not talking about loudness".

With my passive linestage (NOT using any hi-teck LDR), driven by my 1-stage RIAA tube phonostage, I am experiencing excellent music  - "everything top to bottom is amazing".

I can see you enjoy quality music bigtime like I always do. Let me take an example of bass effect from the LP:- the Hollywood-made famous Richard Strauss "Also Aprach Zarathustra". Its sub-sonic opening bars, followed by the heavy sub-sonic pipe organ bass pedal notes, virtually shake up my basement audio den.
It is done thur the 100W 10" sub hooked direct to my passive linestage.
"
Beside the bass. "everything from top to bottom is amazing" for sure.

c-J
« Last Edit: 26 Nov 2012, 05:18 pm by cheap-Jack »

cheap-Jack

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Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #75 on: 26 Nov 2012, 03:54 pm »
Hi.

(1) Now Ralph Karsten feels that passive preamps are nice, but can never reproduce the bass frequencies as well as a properly designed active. As a huge proponent of passive preamps I respectfully disagree with his opinion.

(2) In his opinion it is to control the interconnect. This means not only the ability to drive it, but to control the artifacts.

(3) but the line stage itself will not have any gain and a tube buffered output.

(1) As just posted above, my passive linestage hooked up to my 100W 10" sub can deliver down to 20Hz pipe organ bass pedal notes. The sub used simply to enhance the sub-sonic music & the passive linestage is to 'save-guard' the integrity of the complex music harmonics from otherwise screwed up by an active linestage. So "everything from top to bottom is amazing".

(2) Yes, interconnect capacitance loading is a concern for any passive linestages, particulary to those who   stick to the textbooks.
     But given proper design attention to the O/P coupling capacitance of the phonostage driving it & the interconect run in normal home audio is always short, never miles long, I do not see any problem as I never experienced any drop in HF with my passive linestage at all.

     I don't listen to myths or hearsays which are proved to be untrue with me done it properly.

(3) I am now design/building a very simple active O/P impedance buffer strictly to match the low I/P Z of the built-in power amp module of my 100W 10" sub. Being a die-hard music 'purist', the last thing I would do is to
add any redunctant active devices in the mainstream signal path. I'd allow an active impedance buffer for sub-bass signals only, being off mainstream music signals, IMO.

c-J
     

     
« Last Edit: 26 Nov 2012, 05:45 pm by cheap-Jack »

Clio09

Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #76 on: 26 Nov 2012, 08:02 pm »
Rclark - I find the comments on the Lightspeed and Warpspeed interesting and raises a few questions. Just to be clear, I own both. Alan built me a single input single output balanced unit and I have George's stock unit. Both have dual mono attenuators. I will refer to the thread at DIYAudio to see if I can find my answers since all you did was cut and paste from Alan's post.

Again, I own both and do not notice any discernible difference between the two. They operate a little differently and there are certainly design differences, but to me they perform equally well. The only reason for purchasing the Warpspeed was for the balanced inputs and outputs. George will not make one in this manner and so I give Alan all due credit for being able to design one.

Roger - there is a lengthy thread on DIYAudio.com on the Lightspeed and LDR passives. Nelson Pass even contributes to the thread. You may want to seek it out:

http://www.diyaudio.com/forums/analog-line-level/80194-lightspeed-attenuator-new-passive-preamp.html

Some interesting reading. Also, I must know at least half a dozen people who have used the Lightspeed and your RM-10 with very satisfying results. At under $3k for the set it is IMO the best bargain in audio.

jtwrace

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Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #77 on: 26 Nov 2012, 08:06 pm »
Those are NOT Rclark's comments.  Click the link to see where he copied them from.



Clio09

Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #78 on: 26 Nov 2012, 08:19 pm »
Just saw the link so I will revisit that discussion to see if I can find the specific information. Thanks.

cheap-Jack

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Re: Lesson #1 Video, Topic: Single Stage Preamp Design
« Reply #79 on: 26 Nov 2012, 08:30 pm »
Hi.
I think it would be nice to share more of what you are doing. This is a nice start.

(1) You might state how you have achieved the RIAA EQ, how accurate it is,

(2) how you deal with the variable loading that a passive volume control presents.

(2) I don't understand your comment: "Cathode bias: 2.3V - using no resistor bias which sounds only so so. I have used a much better topology sonically."

(1) This is a pretty complex design of split RIAA equalization using only 1 single triode stage instead of
      commonly used 2 stages. I'd like to defer discussing the entire design.

      Back to yr question re accuary of RIAA high pass (at 500Hz) & low pass filter (at 2,122Hz), whatever discrepancy I don't think our ears can detect at all despite the bench tests can meaure out.

      We should be more concern about the phono cartridge matching the I/P load of the phonstage as
our ears can detect more easily such mismatching than any minor RIAA accuracy offset, IME.

(2) Yes, the textbooks say the hi O/P Z of an anode O/P stage can affect the HF response due to capacitance loading of the interconnects, blah blah...

     No no sweats. Given the proper attenuation of the O/P coupling capactor, the added interconnect capacitance can be offset effectively. Let' me quote the old old paper:- "RCA Receiver Manual R-19" - " 30pF decrease of the O/p capacitor for every foot of interconnect...". 
 
    My picky ears don't have any HF roll-off problem with O/P stage with Hi O/P Z given home audio interconnects are normally short, not miles long! For unlikely case of very long run, than go for an O/P Z buffer. No big deal.

(3)  The cathode bias voltage is 2.3V. The textbooks always use a cathode bias resistor (+bypass cap) to provide such bias voltage - a historic classic.
       This traditional topology unfortunately does not sound very acceptable to my ears. There are always other better sounding alternatives. I have employed a constant voltage source to provide the required
2.3V cathode bias. Guess what it is!

c-J