Yes, his wording is "A varying current enters the circuit and develops a varying voltage as it encounters the resistor and the (T1) triode's cathode impedance in parallel with the resistor."
You have no resistor but a CCS (infinite impedance?).
I was just looking for your wording around this.
Attachments
In the schematic I posted the resistor is the CCS itself (high impedance) in parallel with the triode's cathode impedances, so practically the triode's cathode impedance.
Attachments
Surely a detail in relation to the best shematics which works fine with the TDA1541 !
Is it better to nullify the amp drift at the output (as John e.g. seems to do for reducing noise floor or jitter) or using this drift for first stage tube loading (sorry here for my low understanding !) ?
About the output transformer, maybe many reasons can limit Zanden or AMR : few companies has the knowledge to do excellent outputtransformer and they are expensive, cost in transport, difficult to plan for production and sometimes has to be hand tailored for optimal result or satisfy the designer. I surmise Mr T. to love them and use them like Hiraga who use it on him Nemesis !
But you'r right in an another way from the few I know : good matched with the design, the output cap can allow the designer to mod the sound he likes, even if dielectric losses. The bass will be better with the caps if the transformer is of a bad or middle quality.
The transformer has for itself its isolation... and its better working in the highs for what we want - indeed tubes maid their work before the transformer here?- There are often enough caps in serie on a system...And if able to design myself a preamp, will make it with input transformer !
In a cost aspect : caps win by a large margin with tubes but has defintly find a book to understand how it works.
You are all going to contaminate me with your tubes stories... You looks like old Darksided Sith Jedi talking about very old laser swords !!!! : " Do you remenber how was better the laser swords with a 5687 with a Mu of 0.2 ???... oH yes a killer !: "
Andrea, let ask to Murrano's workers to make us a non microphonic bulbs and let makes a joint venture to retube ancient new stocks from actual production! We needs a dwarf from New Zeland for the cryogenic treatment or a sweden, oer my first wife which was very cold as well !
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Forgive another ignorant dude but L3 bead, is it to stop grid oscillations or to cut uhf-trash from the DAC-chip instead of LP-filter? Or something else maybe?
And why is C1 so big? There must be something there I dont understand. 0,1 uF would be much with a 1 M gridleak usually.
And why is C1 so big? There must be something there I dont understand. 0,1 uF would be much with a 1 M gridleak usually.
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Zanden and AMR also don't worry about exceeding +/-25mV compliance….
Seems this circuit has been discussed at some length before;
http://www.diyaudio.com/forums/digi...-common-gate-valve-i-v-converter-tda1543.html
And is also referred to in the thread about T's tube stage, direct comment etc from post #16 onward.
http://www.diyaudio.com/forums/tubes-valves/197920-thorstens-tube-stage-tda1541a-2.html
Seems this circuit has been discussed at some length before;
http://www.diyaudio.com/forums/digi...-common-gate-valve-i-v-converter-tda1543.html
And is also referred to in the thread about T's tube stage, direct comment etc from post #16 onward.
http://www.diyaudio.com/forums/tubes-valves/197920-thorstens-tube-stage-tda1541a-2.html
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If it's good enough for Zanden & AMR, it's good enough for a wookie ! BTW if I get out all my coats around my ears I can win + 3 db !
Yes the right word is compliance, not drift... you understood me
!
In fact I was refering to this recent input of John which I found interresting with my few knowledge : http://www.diyaudio.com/forums/digi...e-nos-dac-using-tda1541a-516.html#post3990058
Why ? Because it seems to allow very low resistor valor for the passive I/V which is interresting if my understanding is correct ! Though I remenber seen elswhere to go below 18 ohms could be problematic also !
But maybe worth a look before designing your comon tube stage ? Don't know myself... as the output caps I believe the choice of tubes and their subjective qualities in relation to the dac chip must dictate first the design around them !
Thank you Shane for the links... good read for summer holidays...I begann also an english beach roman to try to improve both intelligence and english (mussles are enough as i am wookie and two Leias to protect) : "Merde Actualy" by Stephen Clarke ! The place of the book is our green and beautifull, smooth weather Dordogne & Limousin (not too sunny & not too rainy) which was english before the XIV° century (Plantagenet Kings !). A lot of englishs yet have house here and certainly maid their TDA1541 and Kefs sounding in the forests...
There a lot of Midle-age and more recent castles to put crocodiles in the moats ! Put speakers inside, open the first hifi castle in the world and organise a "bal des vampires" (movie reference) fest could be cool & fun !
Cheers
Yes the right word is compliance, not drift... you understood me
!In fact I was refering to this recent input of John which I found interresting with my few knowledge : http://www.diyaudio.com/forums/digi...e-nos-dac-using-tda1541a-516.html#post3990058
Why ? Because it seems to allow very low resistor valor for the passive I/V which is interresting if my understanding is correct ! Though I remenber seen elswhere to go below 18 ohms could be problematic also !
But maybe worth a look before designing your comon tube stage ? Don't know myself... as the output caps I believe the choice of tubes and their subjective qualities in relation to the dac chip must dictate first the design around them !
Thank you Shane for the links... good read for summer holidays...I begann also an english beach roman to try to improve both intelligence and english (mussles are enough as i am wookie and two Leias to protect) : "Merde Actualy" by Stephen Clarke ! The place of the book is our green and beautifull, smooth weather Dordogne & Limousin (not too sunny & not too rainy) which was english before the XIV° century (Plantagenet Kings !). A lot of englishs yet have house here and certainly maid their TDA1541 and Kefs sounding in the forests...
There a lot of Midle-age and more recent castles to put crocodiles in the moats ! Put speakers inside, open the first hifi castle in the world and organise a "bal des vampires" (movie reference) fest could be cool & fun !
Cheers
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With such that gain, the bead prevents EMI/RFI. Maybe you can use a grid stopper with the 6C45 tube, I prefer the bead. With the tube named The Queen the bead is a good rule, also in the cathode circuit.
An LPF could be used at the output of the DAC rather than before the grid of V1. Someone likes to limit the bandwidth of the TDA1541A, others not. I believe it's a personal choice. Since I'm thinking to a system rather than a simple DAC, I'm planning to run the TDA in NOS at 176 KHz, so I'll avoid any LPF.
About the C1 cap, maybe you can use a 0.1 uF. John Broskie suggests 1 uF in his "more fleshed-out version".
From Thorsthen:
"In practice and with real tubes you will struggle to keep the input (and thus the TDA1541 Output) correctly at 0V, unless you add a servo.
Additionally, the circuit you show uses large amounts of negative feedback to get the very low input impedance and it has several capacitors (including an electrolytic capacitor) in the feedback path.
It may a better choice to just use a decent Op-Amp (OPA637 would be my choice).
In the end it is down to personal preference of course."
The Broskie I to V (and my updated vesion) is a bit different:
there is a DC Servo
almost no phase shift in the feedback loop
no electrolytic capacitor, C5 could be omitted, adding a little local feedback, the eternal question: bypass the cathode resistor or not?
Eldam,
there is a datasheet for the TDA1541A that suggests to not exceed +/-25 mV, and there are different opinions.
IMHO, I believe there is also a simple rule: any current output DAC, as per definition, loves to see a virtual ground at its output.
In general, about this thread and any other about the TDA1541A, pass me the following tasting parallel: are we looking for a Petrus, a Masseto or SUper Market 5 euro Merlot (A Penfolds Grange - obviously Shyra - for the Australian people)?
there is a datasheet for the TDA1541A that suggests to not exceed +/-25 mV, and there are different opinions.
IMHO, I believe there is also a simple rule: any current output DAC, as per definition, loves to see a virtual ground at its output.
In general, about this thread and any other about the TDA1541A, pass me the following tasting parallel: are we looking for a Petrus, a Masseto or SUper Market 5 euro Merlot (A Penfolds Grange - obviously Shyra - for the Australian people)?
I think a simple resistor at the TDA1541a output, with current source to zero the output voltage, is a good option and one that I want to try. The following thread discusses combining that with a simple CCDA tube amplifier.
http://www.diyaudio.com/forums/digital-line-level/157940-tubed-ccda-i-v-amp-tda1541.html
User Radioman62 has shown details of his implementation on his website and gets good results as long as the IV resistors is small - say smaller than 30 ohms. Take a look at the following links:
First DIY DAC, Using TDA1541A and
First DIY DAC, TDA1541A Test with OP vs discrete vs.Tube
I think using a circuit like this and some nice Russian surplus subminiature tubes could be an interesting project.
---Gary
http://www.diyaudio.com/forums/digital-line-level/157940-tubed-ccda-i-v-amp-tda1541.html
User Radioman62 has shown details of his implementation on his website and gets good results as long as the IV resistors is small - say smaller than 30 ohms. Take a look at the following links:
First DIY DAC, Using TDA1541A and
First DIY DAC, TDA1541A Test with OP vs discrete vs.Tube
I think using a circuit like this and some nice Russian surplus subminiature tubes could be an interesting project.
---Gary
Hello Andrea,
"good enough" was the philosophy (i.e. better thant he existing kits of EBAY without of course beating a SOTA AMR/AUDIAL/ECDESIGN off the shelves !
About CD-77 outputstages: just tubes are Massetto/Petrus, not the shematic and parts around...(but the output depend also on the treatment beforethe dac chip... let be positivists but not naives ! )
Keeping the wine analogy, maybe whe have something like this : if your experiments and measurements with you crystal boards and your personal choice about 44.1 at 176 fs are good enough or more according your own standard I surmise to be higher than mine, so why not :
Merlot at less 5 euros : my choice, low money, good quality enough : S-S Cen/Sen
Cabernet Sauvignon + merlot (or Shyraz) at 10 euros to 20 euros (small Chateau) : New tubes and caps, effort can be made on resistors (i/v), output caps : MIT RTX, Mundorf, Riven (your choice but the expensive Teflon... but Russian?... your choice)
Masseto : NOS tubes, even expensive, good supply (tubes rectifier), servo ?, SOTA resistors where it needs, good output transformers of the shelves or SOTA Teflon V cap(?) !
Petrus : the same but with Lundhal, Bartolucci, maid with your own requirement, mumetal shielding, permaloy core !
The lux is the choice : like with your XO : you can or not take it : that's why the Distinve 1541 is so fun : versatile without being bad with its layout... that's what I'm believing into ! Freedom and choice... and good enough for your money in relation to that!
Cheap and good enough could be done as first choice to impact maximum people with the lower cost we can as maid Ryan with the coreboard grup buy. I opened a short thread to allow to understand what could be the best input choice in relation to the Q/P also...
And of course as good contributor, your own freedom too choose your way... open collaborative, each give what he can or want !
As Said Ceglar : not limit here at what can be done when people kindly and smartly collaborate without egoism and ego* !
Btw I try to think to a base line which is hard (not the basline but thinking) : something about philosophy and off shelves to be assembly and inspired by this thread !
Why not :"Our Lego is smarter than your ego !"
"good enough" was the philosophy (i.e. better thant he existing kits of EBAY without of course beating a SOTA AMR/AUDIAL/ECDESIGN off the shelves !
About CD-77 outputstages: just tubes are Massetto/Petrus, not the shematic and parts around...(but the output depend also on the treatment beforethe dac chip... let be positivists but not naives ! )
Keeping the wine analogy, maybe whe have something like this : if your experiments and measurements with you crystal boards and your personal choice about 44.1 at 176 fs are good enough or more according your own standard I surmise to be higher than mine, so why not :
Merlot at less 5 euros : my choice, low money, good quality enough : S-S Cen/Sen
Cabernet Sauvignon + merlot (or Shyraz) at 10 euros to 20 euros (small Chateau) : New tubes and caps, effort can be made on resistors (i/v), output caps : MIT RTX, Mundorf, Riven (your choice but the expensive Teflon... but Russian?... your choice)
Masseto : NOS tubes, even expensive, good supply (tubes rectifier), servo ?, SOTA resistors where it needs, good output transformers of the shelves or SOTA Teflon V cap(?) !
Petrus : the same but with Lundhal, Bartolucci, maid with your own requirement, mumetal shielding, permaloy core !
The lux is the choice : like with your XO : you can or not take it : that's why the Distinve 1541 is so fun : versatile without being bad with its layout... that's what I'm believing into ! Freedom and choice... and good enough for your money in relation to that!
Cheap and good enough could be done as first choice to impact maximum people with the lower cost we can as maid Ryan with the coreboard grup buy. I opened a short thread to allow to understand what could be the best input choice in relation to the Q/P also...
And of course as good contributor, your own freedom too choose your way... open collaborative, each give what he can or want !
As Said Ceglar : not limit here at what can be done when people kindly and smartly collaborate without egoism and ego* !
Btw I try to think to a base line which is hard (not the basline but thinking
) : something about philosophy and off shelves to be assembly and inspired by this thread ! Why not :"Our Lego is smarter than your ego !"
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I dont think Broskies values is choosen for build, just for examples. 1M gridleak and 1 uF cap gives a -3dB frequency drop at 0,16 Hz. A 0,1 uF drops -3 dB at 1,59 Hz. 47 nF drops -3 dB at 3,39 Hz and would be goood enough. The smaller the better bang for the buck.
I was wondering if you had made some filter that I didnt understand but iif the cap is just there to block HV DC then 47 nF is good.
It depends on, among other things, the needed gain. You would want your gain as early as possible in the chain do avoid amplifying additional component noice.
R1, R3 and R9 will be cruical for low noice comps which can be hard with such wattage. One might even think of using chokes there.
Forget Lundahl, I'm not sure Bartolucci will supply in the future.
Find a good vintage Tango, if you are looking for a good transformer.
Return back to the wine analogy: I tasted "decent" not "good" wine for about 20 euro (italian, french, australian, californian), a really good wine starts at 70-100 euro. But if you can spend more than 300 euro one time in your life, try Vega Sicilia Ribera del Duero Unico Gran Reserva 2004, truly heaven.
Can a diyer look for the paradise one time in your life?
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Less than 1W, still possible to find something good.
Chokes are an option, even if more expensive.
Heard about it, very high famous brand...
Totaly agree about wine prices. Can your remenber before euros... it was really less expensive. For 25 euros of now we had the 70-100 euros category !
Not sure we have the same tastes but yes, I would like to test this spanish one but i'm always suscpissious about the too rude weather in Spain, will all the wines I tested from this country. This one can be special, with a good "terroir". Maybe a Grup Buy in my family to taste it if I find a serious shop whith a serious shipping philosophy to its shop ! What is the nearer wine typology in relation to this wine ? Bordeaux ?
Have to try one day the Masseto, i have a preference for the wines of your countrie more than all the other countrie but France, all the good little wines of Venetia e.g. red as white with or without bubles call my glass ! Decent wine elswhere from the fews I drunk (never in the good conditions) but never as complex and quick in the *** as a good St Julien, a good Pomerol, or a Côte-Rôtie in an another way, or like a sweet Chambolle Musigny 1er cru !
Was disapointed e.g. by the chilian Carmenere, "decent good" but not the kick in the ... It was for me a myth as we don't have it. But never drink their more expensive bottles as I found it very very expensive for what it is in relation to the littlier I tested in Q/P ! this mix of weather, sun exposition and ground is a fascinating thing ! Did you ever see in Bourgogne or Bordeaux aeras : 1 km and the wine can be as different than an apple and a peach !
Absolutly, diyer or not you have to do it... in the good conditions as the wine in bottle is a bad traveller !
6Z52P could be worth a try given the sky rocketing prices on D3a/E280F 6?52? / 6Z52P in triode mode | Bartola Valves
Masseto is a very special wine, very expensive, but truly exceptional.
I tasted almost all italian wine, and Masseto is one of the best, maybe the best (I remember 5-6 other type of italian wine that can compete: Trinoro from Tenuta di Trinoro, Barolo Cerequio from Roberto Voerzio, some Barolo/Barbaresco from Gaja, Amarone from Romano Dal Forno, Syrah from Tuarita).
The Vega Sicilia Unico blend is: predominantly Tempranillo with Cabernet Sauvignon, Merlot, Malbec, Carmenere, Albillo. This proportion varies with vintage.
It's a full-bodied but elegant wine at the same time.
Vega Siclia nico 2004. Red wine Ribera del Duero at Decantalo
Good, quality wines at the best price.
I've to say, I mostly drink little wine at 10 euros, I like the little wine of Pays de la Loire as they can be drink often rolleyes and are light and "gouleyant" as some californian and australian are !
I have to taste the Vega one day for a great occasion : very special and complex blend : it can be in the same time deep but soft with complex and long nose smells...
I like the little wines of Venetia, more of 100 types iirc just in this aera : chiquetis and some glass after the work in tratorias is a good tradition as it mix men & women with nice relaxation at the beginning of evening !
Arghhhhhhhhhhh : I would let allow my TDA1541 to sing like Bachus
rolleyes and are light and "gouleyant" as some californian and australian are ! I have to taste the Vega one day for a great occasion : very special and complex blend : it can be in the same time deep but soft with complex and long nose smells...
I like the little wines of Venetia, more of 100 types iirc just in this aera
: chiquetis and some glass after the work in tratorias is a good tradition as it mix men & women with nice relaxation at the beginning of evening ! Arghhhhhhhhhhh : I would let allow my TDA1541 to sing like Bachus
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