Klaus,
for a schematic see cheapskates transformer-coupled linestage on Manfred Huber's webpage.
Replace the Talema toroidal trannie by the Shilton pa102 and also replace SS rectification by a decent vacuum diode rectification and there you are. imagehifi raved about a Euro 9000.- British linestage built like this, and i rave about it too, that is the preamp i am currently using, Manfred lent it to me.
Calculation of transformer primary or choke size:
f = r_p / (2*pi*L)
with f being -3dB frequency, L the load inductance and r_p the plate resistance (Innenwiderstand).
our tube has, say, r_p = 1k and the choke has 50H, our -3dB point of the choke-loaded stage is at 3.18Hz; above the stage gain is equivalent to the tube's µ (open loop gain).
An anode choke has to have the same quality as signal transfomers have to have. No point in using PS or swinging chokes. Magnequest, Shilton and Lundahl sell chokes usable as anode chokes. I use Lundahl.
Frank,
i do not use the same stage topology as Selbstzweck (end-in itself), it came out of design considerations. I wanted to get rid of coupling caps, knowing how even the best mess up the sonics. Choke loaded long-tailed pairs have the beauty that AC-wise, they are DC-coupled and high-z towards the PS. DC-wise lower bandwidth is limited by choke size and they are low-Z towards the PS. So if separate PS( voltage)s are used for the stages, stage n's PS voltage determines stage n+1's grid bias voltage and it does so rock-solid, low-Z, without drift. Quite soothing in a DC-coupled amp.
Now the only cause for the amp stages so sit in the corner and not at desired operating point is 1) warmup-effects and 2) tube parameter imbalance (caused by poor matching or by aging of the tubes). So each stage n has a small variable resistor in series with the one of the chokes to balance stage n+1. Has to be done regularly.
for a schematic see cheapskates transformer-coupled linestage on Manfred Huber's webpage.
Replace the Talema toroidal trannie by the Shilton pa102 and also replace SS rectification by a decent vacuum diode rectification and there you are. imagehifi raved about a Euro 9000.- British linestage built like this, and i rave about it too, that is the preamp i am currently using, Manfred lent it to me.
Calculation of transformer primary or choke size:
f = r_p / (2*pi*L)
with f being -3dB frequency, L the load inductance and r_p the plate resistance (Innenwiderstand).
our tube has, say, r_p = 1k and the choke has 50H, our -3dB point of the choke-loaded stage is at 3.18Hz; above the stage gain is equivalent to the tube's µ (open loop gain).
An anode choke has to have the same quality as signal transfomers have to have. No point in using PS or swinging chokes. Magnequest, Shilton and Lundahl sell chokes usable as anode chokes. I use Lundahl.
Frank,
i do not use the same stage topology as Selbstzweck (end-in itself), it came out of design considerations. I wanted to get rid of coupling caps, knowing how even the best mess up the sonics. Choke loaded long-tailed pairs have the beauty that AC-wise, they are DC-coupled and high-z towards the PS. DC-wise lower bandwidth is limited by choke size and they are low-Z towards the PS. So if separate PS( voltage)s are used for the stages, stage n's PS voltage determines stage n+1's grid bias voltage and it does so rock-solid, low-Z, without drift. Quite soothing in a DC-coupled amp.
Now the only cause for the amp stages so sit in the corner and not at desired operating point is 1) warmup-effects and 2) tube parameter imbalance (caused by poor matching or by aging of the tubes). So each stage n has a small variable resistor in series with the one of the chokes to balance stage n+1. Has to be done regularly.
L'Audiophile LeTube
Torben,
folowed your link, went into my bookmarks, thanxalot!
I found the L'Audiophile LeTube in it.
to all tube newbies and those planning an integrated tube amp:
the LeTube preamp is incapable of driving nasty loads and/or legnthy and/or highly capacitive interconnects.
As preamp section of an integrated tube amp it is breathtakingly good and simple to implement. Sonics are a blast, just incredible.
I build one once for a friend and tweaked it a bit, non-magnetic resistors and Roederstein MKP 1841 shunted with 1n of mica as coupling cap.
Be aware that RIAA is deviant in the 20 Hz region and it varies with tube aging and change. But then .. who cares, such sonics considered.
High PS voltage: could be seroiusly reduced by replacing the anode resistors by CCSs. Without sonic punishment IMO.
Torben,
folowed your link, went into my bookmarks, thanxalot!
I found the L'Audiophile LeTube in it.
to all tube newbies and those planning an integrated tube amp:
the LeTube preamp is incapable of driving nasty loads and/or legnthy and/or highly capacitive interconnects.
As preamp section of an integrated tube amp it is breathtakingly good and simple to implement. Sonics are a blast, just incredible.
I build one once for a friend and tweaked it a bit, non-magnetic resistors and Roederstein MKP 1841 shunted with 1n of mica as coupling cap.
Be aware that RIAA is deviant in the 20 Hz region and it varies with tube aging and change. But then .. who cares, such sonics considered.
High PS voltage: could be seroiusly reduced by replacing the anode resistors by CCSs. Without sonic punishment IMO.
Frank
I understand. Since PS you presented doesn`t reqire some enormes cost to build, and there is no need for any dramatic changes in the basic circuit, I`ll try boath versions of plate load reg. I`m interested what should I do to implement const.cour.sourse using n-fet in original Hampton PS if posible. (BTW sorry about those newbi quest`s, but two years ago I couldn`t tell the diference betwin cap and resistor on a shematic--today my DIY aleph`s and my el34 int.amp are working just fine so, I`m lerning)
What is your sugestion regarding transformers for this kind of aplication, EI, toroid...?
regards Marijan
I understand. Since PS you presented doesn`t reqire some enormes cost to build, and there is no need for any dramatic changes in the basic circuit, I`ll try boath versions of plate load reg. I`m interested what should I do to implement const.cour.sourse using n-fet in original Hampton PS if posible. (BTW sorry about those newbi quest`s, but two years ago I couldn`t tell the diference betwin cap and resistor on a shematic--today my DIY aleph`s and my el34 int.amp are working just fine so, I`m lerning)
What is your sugestion regarding transformers for this kind of aplication, EI, toroid...?
regards Marijan
Hello Marjan,
Re yr questions,
Personally I prefer EI core trannies although in case you build the circuit in the same box as the psu toroid will have less stray inductance and would induce less hum.
The Hampton circuit should be built as it is,it would require a complete rethinking job to implement a ccs.
As I mentioned before:I try to keep it simple,there's is no point in going overboard in adding things for the sake of it.
BTW the fets will require some selection for equal idss,the voltage drop should be about 1 V across them,variations will lead to slightly (but audible) differences in gain between channels.
If you have access to a good tube tester select your ECC88's for close matching between channels.
Also if anything will ever die in this circuit it will most likely be the Fets:they are sensitive to heating up too long with a soldering iron.(I speak from experience when experimenting with different coupling caps so be forewarned.)
Anyway this is my personal point of view,others may differ.
Feel free to experiment.
Pls.do not apologise for being a newbie to this.We all started somewhere along the same lines.
Rgds,
Re yr questions,
Personally I prefer EI core trannies although in case you build the circuit in the same box as the psu toroid will have less stray inductance and would induce less hum.
The Hampton circuit should be built as it is,it would require a complete rethinking job to implement a ccs.
As I mentioned before:I try to keep it simple,there's is no point in going overboard in adding things for the sake of it.
BTW the fets will require some selection for equal idss,the voltage drop should be about 1 V across them,variations will lead to slightly (but audible) differences in gain between channels.
If you have access to a good tube tester select your ECC88's for close matching between channels.
Also if anything will ever die in this circuit it will most likely be the Fets:they are sensitive to heating up too long with a soldering iron.(I speak from experience when experimenting with different coupling caps so be forewarned.)
Anyway this is my personal point of view,others may differ.
Feel free to experiment.
Pls.do not apologise for being a newbie to this.We all started somewhere along the same lines.
Rgds,
Hello Bernhard,
This maybe beside the point but still:
-As I understand it your circuit topology requires the user to adjust for drift on a regular basis.I think this is Ok for someone like yourself but surely unacceptable (no offense ) for the everyday user ?
-What I don't understand though is that you try to regulate the PSU on a preamp where hardly any current is flowing.For a choke to regulate sufficient currentflow is required,too much of it and it will swing and saturate it's core.Am I missing something here ?
-My approach to the problem is active valve regulation on a per stage/channel basis : series pass device/comparator/voltage reference tube.
When implemented correctly this is rock solid and has low Z.
-Ok,so you need to adjust things after switch on probably because the tubes need their cathodes to reach operating temperature.If this is the case you're very likely to damage the tubes.
One solution would be to use a valve rectifier EZ81 style and in case you argue about the sonic impact you can still get around it by a timer such as a N555 which would trigger a nasty rectifier bridge once operating voltage have stabilized ?
Active regulation with valves would also give you a slow and natural ramp up of B+.
Most people don't realise this but most components get killed at switch on,valves are even more prone to damage since they depend on their cathodes to operate.If one doesn't respect this cathode "stripping" will occur.
To Torben and Bernhard,
" found the L'Audiophile LeTube in it."
Having lived the haydays of "L'Audiophile" I can add just this :
"Le tube" is a shake and mix of the Dynaco PAS 3 and the Marantz 7C .Not to say it has no merit BUT : it has high output Z so long capacitive (all are by nature) interconnects are a definite "nono" and moreover RIAA correction is not accurate at all and will vary with ageing tubes (Global NFB).
One can circumvent the output impedance by addding a White cathode follower using ECC82 or better still a 12BH7.If you want to keep things really small a pair of 12DW7's would do the trick.
Anyone having compactrons ?
Still it would be a nice starting point for any audiophile with MM cartidge setup and a tight budget.
Let it be understood that I really don't want to step on anyones toes here,just trying to inform.
Keep up the good work,
This maybe beside the point but still:
-As I understand it your circuit topology requires the user to adjust for drift on a regular basis.I think this is Ok for someone like yourself but surely unacceptable (no offense ) for the everyday user ?
-What I don't understand though is that you try to regulate the PSU on a preamp where hardly any current is flowing.For a choke to regulate sufficient currentflow is required,too much of it and it will swing and saturate it's core.Am I missing something here ?
-My approach to the problem is active valve regulation on a per stage/channel basis : series pass device/comparator/voltage reference tube.
When implemented correctly this is rock solid and has low Z.
-Ok,so you need to adjust things after switch on probably because the tubes need their cathodes to reach operating temperature.If this is the case you're very likely to damage the tubes.
One solution would be to use a valve rectifier EZ81 style and in case you argue about the sonic impact you can still get around it by a timer such as a N555 which would trigger a nasty rectifier bridge once operating voltage have stabilized ?
Active regulation with valves would also give you a slow and natural ramp up of B+.
Most people don't realise this but most components get killed at switch on,valves are even more prone to damage since they depend on their cathodes to operate.If one doesn't respect this cathode "stripping" will occur.
To Torben and Bernhard,
" found the L'Audiophile LeTube in it."
Having lived the haydays of "L'Audiophile" I can add just this :
"Le tube" is a shake and mix of the Dynaco PAS 3 and the Marantz 7C .Not to say it has no merit BUT : it has high output Z so long capacitive (all are by nature) interconnects are a definite "nono" and moreover RIAA correction is not accurate at all and will vary with ageing tubes (Global NFB).
One can circumvent the output impedance by addding a White cathode follower using ECC82 or better still a 12BH7.If you want to keep things really small a pair of 12DW7's would do the trick.
Anyone having compactrons ?
Still it would be a nice starting point for any audiophile with MM cartidge setup and a tight budget.
Let it be understood that I really don't want to step on anyones toes here,just trying to inform.
Keep up the good work,
Hi
Does this bring back memories? About 17 years ago i spend quite some time struggling with an ECC88 based step-up. Briefly tried paralleling, but the loss in ambience was not worth the minor s/n gain. Also tried all kinds of active current sources and although they all sounded dynamic and hifiyish at the end settled for tantalum resistors. Anode power came from a string of nicads, everything else sounded like a very poor compromise. I think around 36v. It sounded fairly decent. My only regret being, not having plate chokes to try - today i really love choke loaded line and driver stages.
peter
Does this bring back memories? About 17 years ago i spend quite some time struggling with an ECC88 based step-up. Briefly tried paralleling, but the loss in ambience was not worth the minor s/n gain. Also tried all kinds of active current sources and although they all sounded dynamic and hifiyish at the end settled for tantalum resistors. Anode power came from a string of nicads, everything else sounded like a very poor compromise. I think around 36v. It sounded fairly decent. My only regret being, not having plate chokes to try - today i really love choke loaded line and driver stages.
peter
Frank,
i intended to feed each stage on each channel with a separate shunt reg.
1st stage: 2x EC8010 or 5842, 2x 25mA
2nd stage: 2x 12A4 2x 23mA or 2x 5842, 2x 25 mA
3rd stage: 2x 12B4, 2x 34mA.
I would not call that close to zero current. 164mA per channel, would quite a beast of a shuntreg and then, how do i get each stage's B+ where i want it for DC-coupling.
Better separate regs. And no interstage crosstalk via the PS. And i have the only really expensive thing of those shunt regs already: MKV caps to sit on. I have 120 or so.
Rectifiers will be a quad of fat TV damper diodes like the 6CM3. A Graetz bridge of them will deliver 800mA. That will do.
You point with the heatup are well taken.
I like soft start provided by tube rectifiers and i lave the absence of garbage injected by SS recitifiers in maplifier and wall outlet.
Manual balancing could also be done by a µC and cheap stepper motors. IN the future. But i will have to try out 1st how much imbalance this preamp takes. And how this develops with tube aging.
This is a preamp with DC-coupling over 3 stages and adjsting ablace from time to time will be a small price for that. Dunno if i get this product of insanity running at all, but if i succeed, i will not complain about adjusting the balance now and then.
i intended to feed each stage on each channel with a separate shunt reg.
1st stage: 2x EC8010 or 5842, 2x 25mA
2nd stage: 2x 12A4 2x 23mA or 2x 5842, 2x 25 mA
3rd stage: 2x 12B4, 2x 34mA.
I would not call that close to zero current. 164mA per channel, would quite a beast of a shuntreg and then, how do i get each stage's B+ where i want it for DC-coupling.
Better separate regs. And no interstage crosstalk via the PS. And i have the only really expensive thing of those shunt regs already: MKV caps to sit on. I have 120 or so.
Rectifiers will be a quad of fat TV damper diodes like the 6CM3. A Graetz bridge of them will deliver 800mA. That will do.
You point with the heatup are well taken.
I like soft start provided by tube rectifiers and i lave the absence of garbage injected by SS recitifiers in maplifier and wall outlet.
Manual balancing could also be done by a µC and cheap stepper motors. IN the future. But i will have to try out 1st how much imbalance this preamp takes. And how this develops with tube aging.
This is a preamp with DC-coupling over 3 stages and adjsting ablace from time to time will be a small price for that. Dunno if i get this product of insanity running at all, but if i succeed, i will not complain about adjusting the balance now and then.
marjan said:
What I have found out, just by reading audio tube stuff (be warned, I have not listened to the tube. I gave up listening to my trasistors as well, I couldn't hear a thing)
ECC88 is the most interesting double triode I know of.
It can use and deliver somewhat more current,
and can also be used with a little lower anode voltage
than other triodes.
So if chosing a triode for preamplifiers or even
headphone amplifiers, ECC88/6922 is HIGH on my list.
You can even parallell 2 of them at the output
give more current out.
An alternative for me would be EF86 in TRIODE mode.
It is a penthode with good performance.
That is about what I've learned READING about tubes, so far.
I'll come back if I become any wiser regarding this
special subject in audio circuit design.
I did not want to include the personal taste regarding sonical caracteristi`s of hi-fi ( high end - whatever) equipment in tread like that, but it is a fact. In theory some products or designs can look georgeus and not discusionable. Lot of them does sound great too. But when we leave the circuit discusion level moving to the completed product, we can talk about the sonical efects that the component is able to deliver. Perception of sonical caracteristic`s is subjectiv. That is why my question on the start of the tread regarding choice of the tube included "based on personal expirience with that tube". What I`m trying to say is that every aproach will be sonicly satisfying for some and the oposit for some one else. Every aproach shoud go along with the demands we have to a given component in the therms of reliability, stability, and most natural reproduction of the recorded meterial a supouse. To give a judgement of the design or aplication of dif. parts in it, I supouse it should be built first, so you can test, listen and make your owne opinion. That is helpfull and good to share.
Since there is a debate about diferent aproach, not only about PS and regulation of it, but about using diferent tubes from single triode, paralel double to the chain of two or even more double triods (aybe it woul`d be good to use, let say two perfectly matched sigel oens in paralel conection or even more of them, since you (a supouse) do not hawe two perfectly matched sections in one double). Obviously it is possible to use diferent tues in a input stage of such of design. ECC88/6DJ8/6922 is like to be prowen as the most comon (the best?).
I`d like to refrase my question leeding us to the start point of design.
Which electrical parameter`s of the tube are the most important in such a design? What are the ideal tehnical operating carasteristic`s of the input tube if you are planing to design MC step up modul. Knowing that, designeing and disision`s about chousing aproach, woul`d be much easier. I know that ansver to that, demand wide global knowlidge on the field of ellectronic and acoustic, butI`d like to see a kind of short imagenary data sheet of the tube it woud be ideal for the purpouse.
rgds Marijan
Since there is a debate about diferent aproach, not only about PS and regulation of it, but about using diferent tubes from single triode, paralel double to the chain of two or even more double triods (aybe it woul`d be good to use, let say two perfectly matched sigel oens in paralel conection or even more of them, since you (a supouse) do not hawe two perfectly matched sections in one double). Obviously it is possible to use diferent tues in a input stage of such of design. ECC88/6DJ8/6922 is like to be prowen as the most comon (the best?).
I`d like to refrase my question leeding us to the start point of design.
Which electrical parameter`s of the tube are the most important in such a design? What are the ideal tehnical operating carasteristic`s of the input tube if you are planing to design MC step up modul. Knowing that, designeing and disision`s about chousing aproach, woul`d be much easier. I know that ansver to that, demand wide global knowlidge on the field of ellectronic and acoustic, butI`d like to see a kind of short imagenary data sheet of the tube it woud be ideal for the purpouse.
rgds Marijan
Marjan,
sorry for having gone off-topic, but Frank did ask me and i thouhgt i'd answer, did not intend to threadjack your thread.
Apart form the fact such thing as facts do not exist i agree with you.
To your QQ:
I doubt parameters alone can determine what tube to use. But one thing is sure: the higher the tube's transconductance, the lower the thermal noise. Shot noise is unaffected by transcondictance, but thermal noise reduces by 3dB each time the count of the parallelled tube section is doubled.
The ECC88 is a very good choice as it has enough transconductance and runs from low B+, not all such tubes do that or are spec'ed and documented for that. It is not a good choice as it gets noisy soon, apart from whizzing (which can annoy much) shot noise increases.
The tube for your purpose must have high transconductance, ultra low microphonics, and with a current souce you need a µ of 10 atleast, with anode resistor a µ of 20 .
It should be able to run with low or zero grid bias like the ECC88.
But before i would use parallelled sections, i would use a tube with twice the transconductance.
5842 or EC8010 e.g. and these tubes also are proved to have good sonics.
The ECC88 has not an ideal transfer characteristics curve, already decreasing slope in the negative bias area, it generates more k3 than most other audio triodes. But for MC swing (signal amplitude) that does not count at all.
You must try out which tube works best for you. Not much experinece out there
sorry for having gone off-topic, but Frank did ask me and i thouhgt i'd answer, did not intend to threadjack your thread.
Apart form the fact such thing as facts do not exist
i agree with you.To your QQ:
I doubt parameters alone can determine what tube to use. But one thing is sure: the higher the tube's transconductance, the lower the thermal noise. Shot noise is unaffected by transcondictance, but thermal noise reduces by 3dB each time the count of the parallelled tube section is doubled.
The ECC88 is a very good choice as it has enough transconductance and runs from low B+, not all such tubes do that or are spec'ed and documented for that. It is not a good choice as it gets noisy soon, apart from whizzing (which can annoy much) shot noise increases.
The tube for your purpose must have high transconductance, ultra low microphonics, and with a current souce you need a µ of 10 atleast, with anode resistor a µ of 20 .
It should be able to run with low or zero grid bias like the ECC88.
But before i would use parallelled sections, i would use a tube with twice the transconductance.
5842 or EC8010 e.g. and these tubes also are proved to have good sonics.
The ECC88 has not an ideal transfer characteristics curve, already decreasing slope in the negative bias area, it generates more k3 than most other audio triodes. But for MC swing (signal amplitude) that does not count at all.
You must try out which tube works best for you. Not much experinece out there
Re: stein line stage with ecc88
Klaus,
to me this looks like an integrated CCS with R3 as current sensing resistor, acting as active load for the tube. With SW1 open, this stage will have gain of 33. Like the µ of the tube. Sw1 closes neg. feedback loop.
To me this looks not like an SRPP. The CCS simulates an almost infinite resistance so R3 is irrelevant as far as output swing is concerned.
Klaus,
lohk said:
to me this looks like an integrated CCS with R3 as current sensing resistor, acting as active load for the tube. With SW1 open, this stage will have gain of 33. Like the µ of the tube. Sw1 closes neg. feedback loop.
To me this looks not like an SRPP. The CCS simulates an almost infinite resistance so R3 is irrelevant as far as output swing is concerned.
Frank
supouse that I`m using 230/100V EI transformer for anode suply
would it still be sutiable at 30VA rating, one chanal each (I found them in a local store at resonable price)? You mentioned that 100mA is moore than enough. And at home I stil have some EI I could use for heater suply230/12V-10VA trans. OK no OK?
Bernhard
I did not try to get specific numbers regarding parameters of the tube. I just wanted to know what demands (in parametric form) designer of the circuit is puting in front of the thube which is intended to be in use as the MC input stage in the MC step up modul. Your ansvers are helpfull enough to me.
Thank`s
Lohk
thank you for posting those shematics
BTW, what would be a diference betwin using one double ECC88 triode in paralel section conection and two matched (sutiable for the purpouse) single triode`s allso in paralel conection. Any benefit or any diference from second variation at all?
rgds to all
supouse that I`m using 230/100V EI transformer for anode suply
would it still be sutiable at 30VA rating, one chanal each (I found them in a local store at resonable price)? You mentioned that 100mA is moore than enough. And at home I stil have some EI I could use for heater suply230/12V-10VA trans. OK no OK?
Bernhard
I did not try to get specific numbers regarding parameters of the tube. I just wanted to know what demands (in parametric form) designer of the circuit is puting in front of the thube which is intended to be in use as the MC input stage in the MC step up modul. Your ansvers are helpfull enough to me.
Thank`s
Lohk
thank you for posting those shematics
BTW, what would be a diference betwin using one double ECC88 triode in paralel section conection and two matched (sutiable for the purpouse) single triode`s allso in paralel conection. Any benefit or any diference from second variation at all?
rgds to all
Marjan,
Whilst browsing I noticed no one actually answered the last part of yr. q.
Regarding any diffs in using separate single triodes or twin ones:
I see more drawbacks in using separates ones from virtually all angles of design:more sockets ,wiring etc.
If you really want to get as close to perfection as possible on the tubes here I would select them with both sections paralled for high Gm and low noise after I gave them a couple of days of burn in.
Maybe a good dealer could do this for you ?
Greetz,
Whilst browsing I noticed no one actually answered the last part of yr. q.
Regarding any diffs in using separate single triodes or twin ones:
I see more drawbacks in using separates ones from virtually all angles of design:more sockets ,wiring etc.
If you really want to get as close to perfection as possible on the tubes here I would select them with both sections paralled for high Gm and low noise after I gave them a couple of days of burn in.
Maybe a good dealer could do this for you ?
Greetz,
Hello Peter,
Does this bring back memories?
Sorry for the late reaction,I was trying to put Marjan on track.
Regarding the circuit you talk about...I tried the same work arounds as your self.
I gave up on the batteries for practical reasons no more applying now.In short the battery supply for the 24V B+ would surely be worthy of consideration.
After all other than the heater supply,the anodes only consume 1 mA per tube.(In this particular application.)
You could still integrate a choke AND a CCS.
I would still decouple the batteries with a few mF of polyprops though.
Listening tests done by the French L'Audiophile team suggested the batteries they used for tests on the development of the "Le Monstre" transistor amp were rather dirty sounding in the highs.
Admittedly it was a rather over the top expirement.
Have you considered other valve based solutions ?
To Lock,
Thanks for this Dusan Klimo circuit.Having met the designer on several occasions and moreover having listened to his designs I came to respect his work a lot.
I think his circuit is a very good compromise considering the combination with his Merlin preamp.
Very possibly one of the best prepre's I've seen on paper.
Unfortunately I never had the chance to listen to it.Did you?
Greetz,
Does this bring back memories?
Sorry for the late reaction,I was trying to put Marjan on track.
Regarding the circuit you talk about...I tried the same work arounds as your self.
I gave up on the batteries for practical reasons no more applying now.In short the battery supply for the 24V B+ would surely be worthy of consideration.
After all other than the heater supply,the anodes only consume 1 mA per tube.(In this particular application.)
You could still integrate a choke AND a CCS.
I would still decouple the batteries with a few mF of polyprops though.
Listening tests done by the French L'Audiophile team suggested the batteries they used for tests on the development of the "Le Monstre" transistor amp were rather dirty sounding in the highs.
Admittedly it was a rather over the top expirement.
Have you considered other valve based solutions ?
To Lock,
Thanks for this Dusan Klimo circuit.Having met the designer on several occasions and moreover having listened to his designs I came to respect his work a lot.
I think his circuit is a very good compromise considering the combination with his Merlin preamp.
Very possibly one of the best prepre's I've seen on paper.
Unfortunately I never had the chance to listen to it.Did you?
Greetz,
Hi frank
I`m in the proces of soldering parts for my MC pre-pre already using basic design.
Still trying to get proper output caps. I have 1uF Wima MKP`s for now. Dont know if they will be perfect for this aplication but for the testing purpouse they`ll do. Thinking of bypasing them with the 100p Micaas but I can see diferent opinions about that on some treads -I`ll just try. I supouse I`ll have to open my purse and get some oil caps or similar.
Tubes. I just wondered if there is any benefit of using single`s in parallel mostly becouse it is easyer to find matched par than double with matched sections, but I supouse that it not to critical parameter, so I`m going for parall. double. I shoud finish the projectin week or two. I`ll post my impresions.
regards
Marijan
I`m in the proces of soldering parts for my MC pre-pre already using basic design.
Still trying to get proper output caps. I have 1uF Wima MKP`s for now. Dont know if they will be perfect for this aplication but for the testing purpouse they`ll do. Thinking of bypasing them with the 100p Micaas but I can see diferent opinions about that on some treads -I`ll just try. I supouse I`ll have to open my purse and get some oil caps or similar.
Tubes. I just wondered if there is any benefit of using single`s in parallel mostly becouse it is easyer to find matched par than double with matched sections, but I supouse that it not to critical parameter, so I`m going for parall. double. I shoud finish the projectin week or two. I`ll post my impresions.
regards
Marijan
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