I would like to do these mods but I remember in the documents of Mr. Kaneda he does not prefer to remover the solder after of the PCB since its very fragile after all this time and I wanted to make the cable more neat but these cable are too thin and hard to solder. I would look into building a new one with your recommendations (parts and PCB). Since I always wanted to modify and tweak the phono equalization to make it suits my Studer recorders making 15 IPS IEC equalization or this is only me dreaming to have it overall ☕ see picture. If you think I can find and buy the parts specially the 2SK170 or 2SK30GRY and good caps I would be really into it.
Thanks.
Thanks.
I think it can be nice. However . . do you have the circuit of the studer equalizr . It can well be a double-T filter. (at least my other brand studio recorder had that) That would be pretty good; so I would try to retain that part.
Hi, just found a source for the chokes. It's in Italy, don't know if they ship international. I have no connection (nor interest) with them, but if you need I would contact them, let me know.
https://shop.piemme-elektra.it/Products/8569
Guido
https://shop.piemme-elektra.it/Products/8569
Guido
Hello,
I checked the original publication the power supply going into the circuit is 35 volts. The French did make a few designs with caps used very close to their maximum voltage. If the ac voltage from the wall is just a bit higher you are already stressing the caps to much. Minimum would be 40 volt cap which you could protect with a big 38 volt zener to be sure.
Greetings Eduard
P.s another publication shows 63 volt caps before the choke and 40 volts after the choke
P.s there is an original kaneda with regulated supply on ebay in the usa
I checked the original publication the power supply going into the circuit is 35 volts. The French did make a few designs with caps used very close to their maximum voltage. If the ac voltage from the wall is just a bit higher you are already stressing the caps to much. Minimum would be 40 volt cap which you could protect with a big 38 volt zener to be sure.
Greetings Eduard
P.s another publication shows 63 volt caps before the choke and 40 volts after the choke
P.s there is an original kaneda with regulated supply on ebay in the usa
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Guido, My suggestion is: take any toroid for a power supply
- with two 110V primaries that can be paralelled. The capability to parallel implies that the two windings are identical otherwise the toroid would warm up (there would be a short).
- And the same can be said of two secondaries that can be paralleled - they even more have to be equal. And that has lower Rdc.
Hello,
Better a split bobbin because it will filter much more garbage from the power line.
Two lundahl chokes for a choke input and ready to go.
And check the voltages on the 35 volt caps. The French take to much risk with these.
Greetings Eduard
Better a split bobbin because it will filter much more garbage from the power line.
Two lundahl chokes for a choke input and ready to go.
And check the voltages on the 35 volt caps. The French take to much risk with these.
Greetings Eduard
Greetings All,
Thanks all for joining the discussion and I apologize for my late response I have been traveling lately.
You are right caps are 35v 39,000uF that was provided y the kit. Mine now working with +-34.78v with all original parts except for the additional big caps 0.1F 75v I have installed before year a go which makes the big change in the base. However, operating the caps with near to their rating voltages provide the best ripple voltage even though it will be dangerous. Also the power transformer I have it has additional windings 35v so that its 35v 25v 0 25v 35v transformer.
As advised per Mr.Eduard for chokes LL2742,
I like the idea of adding new chokes but this will require to have a new power transformer. I will explain the Math for calculating the new power transformer. First, notes from the documents that illustrates wee can operate the preamp with voltage rails from 33.5 to 37v but I will make sure it is close to 35v as per the documents. Voltage drop will follow ohms low for CRCLC filter. Choke will be used LL2742 80 ohms thanks to Edward. I assume the current to be 0.1A (I will confirm with the actual readings later) and this will give voltage drop of 8v and if R to be 1 ohm this will give 0.1v as minimum total of 9V to 10V which will require a power transformer of the range of 32v AC to 30v AC. (32*1.43-10 = 35.76v) I can always change the voltage drop by using different R. So If I can find a transformer with multiple taps 32 31 0 31 32 I can change between them to get the best performance. Please correct Me if I am wrong.
Thanks
Ahmed
Thanks all for joining the discussion and I apologize for my late response I have been traveling lately.
You are right caps are 35v 39,000uF that was provided y the kit. Mine now working with +-34.78v with all original parts except for the additional big caps 0.1F 75v I have installed before year a go which makes the big change in the base. However, operating the caps with near to their rating voltages provide the best ripple voltage even though it will be dangerous. Also the power transformer I have it has additional windings 35v so that its 35v 25v 0 25v 35v transformer.
As advised per Mr.Eduard for chokes LL2742,
I like the idea of adding new chokes but this will require to have a new power transformer. I will explain the Math for calculating the new power transformer. First, notes from the documents that illustrates wee can operate the preamp with voltage rails from 33.5 to 37v but I will make sure it is close to 35v as per the documents. Voltage drop will follow ohms low for CRCLC filter. Choke will be used LL2742 80 ohms thanks to Edward. I assume the current to be 0.1A (I will confirm with the actual readings later) and this will give voltage drop of 8v and if R to be 1 ohm this will give 0.1v as minimum total of 9V to 10V which will require a power transformer of the range of 32v AC to 30v AC. (32*1.43-10 = 35.76v) I can always change the voltage drop by using different R. So If I can find a transformer with multiple taps 32 31 0 31 32 I can change between them to get the best performance. Please correct Me if I am wrong.
Thanks
Ahmed
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Hello,
34,78 volt on a 35 volt could sound good ( i doubt that ) but one day it will go boom.
If there is a safety vent it will spray chemical stuff all over the inside of your preamp.
I would just use a pair of 47000 microfarad 40 volts made by German F&T . Aim for a dc voltage between 33 en 34 volt and mount 35( or a string ) volt big zenerdiodes across the caps to protect the transistors on the circuit board.
Greetings,Eduard
P.s of course ohms law not works for choke input
34,78 volt on a 35 volt could sound good ( i doubt that ) but one day it will go boom.
If there is a safety vent it will spray chemical stuff all over the inside of your preamp.
I would just use a pair of 47000 microfarad 40 volts made by German F&T . Aim for a dc voltage between 33 en 34 volt and mount 35( or a string ) volt big zenerdiodes across the caps to protect the transistors on the circuit board.
Greetings,Eduard
P.s of course ohms law not works for choke input
Hello,
We will be getting some help with someone who has access to psud ( out of my country so no Windows) to make a choke input supply.
We have to check the actual current being drawn. I expect a big leap forward by using a nicely constructed choke input supply.
Greetings, Eduard
One issue we have Mouser does not ship to Saudi Arabia.
We will be getting some help with someone who has access to psud ( out of my country so no Windows) to make a choke input supply.
We have to check the actual current being drawn. I expect a big leap forward by using a nicely constructed choke input supply.
Greetings, Eduard
One issue we have Mouser does not ship to Saudi Arabia.
Hello,
I did not see the original poster message to me. He measured around 230 mA for both positive and negative side of the supply. Isn't that an awful lot for a solid state preamp with line and phonostage inside?
The present supply has a clc supply with a choke with 20 ohm dcr. Online i found a drawing which indicates about 1,5 voltage drop across the choke which seems more realistic. Maybe there is a leaky power cap somewhere on the board. I have the choke too and it has tiny wires, not suitable for 230 mA i think.
The original power cap is joined by a bigger cap. The original cap Is 35 volt with around 34,5 volt present. It is 39000 microfarad adding that cap will create around 12 mA extra current. That is a lot or not?
Something must be wrong i think. I am in Vietnam now i have no access to my paper Library .
It makes a lot of difference if we have to get a choke for let us say 100mA or 250mA. One we could get 20H and the other will have much less H, maybe 4H
Greetings Eduard
I did not see the original poster message to me. He measured around 230 mA for both positive and negative side of the supply. Isn't that an awful lot for a solid state preamp with line and phonostage inside?
The present supply has a clc supply with a choke with 20 ohm dcr. Online i found a drawing which indicates about 1,5 voltage drop across the choke which seems more realistic. Maybe there is a leaky power cap somewhere on the board. I have the choke too and it has tiny wires, not suitable for 230 mA i think.
The original power cap is joined by a bigger cap. The original cap Is 35 volt with around 34,5 volt present. It is 39000 microfarad adding that cap will create around 12 mA extra current. That is a lot or not?
Something must be wrong i think. I am in Vietnam now i have no access to my paper Library .
It makes a lot of difference if we have to get a choke for let us say 100mA or 250mA. One we could get 20H and the other will have much less H, maybe 4H
Greetings Eduard
with 17W of dissipation everything would be smoked inside
each OS is drawing around 7mA (simple calc - 35V rail divided with 4K7 loading resistor), so that's 28mA for 4 OS-es ( 2 phono channels, 2 line channels, all having same transistor in upper rail loaded with 4K7 in lower rail)
everything in front is drawing even less
and I can't see anything resembling shunt reg or even just shunting elements in PSU, nor I think that small Donut is having more than , say, 25VA
error in measurement, especially if preamp is actually producing music
each OS is drawing around 7mA (simple calc - 35V rail divided with 4K7 loading resistor), so that's 28mA for 4 OS-es ( 2 phono channels, 2 line channels, all having same transistor in upper rail loaded with 4K7 in lower rail)
everything in front is drawing even less
and I can't see anything resembling shunt reg or even just shunting elements in PSU, nor I think that small Donut is having more than , say, 25VA
error in measurement, especially if preamp is actually producing music
Hello,
I had my serious doubts too.
So happy you can confirm it.
Greetings Eduard
P.s so a choke rated for let us 60 mA ( including bleeder to assure minimum current) would be sufficient?
I had my serious doubts too.
So happy you can confirm it.
Greetings Eduard
P.s so a choke rated for let us 60 mA ( including bleeder to assure minimum current) would be sufficient?
I would rather go to 100mA declared choke
bleeders or not, depends of everything else
decision to make after build and measurements what's happening in power on sequence
I'm personally solving all my puzzles (in context) with shunt regs, negating such overkill approach as shown here (zillion of mF), but that's just me
bleeders or not, depends of everything else
decision to make after build and measurements what's happening in power on sequence
I'm personally solving all my puzzles (in context) with shunt regs, negating such overkill approach as shown here (zillion of mF), but that's just me
Hello,
I also was wondering why I would have a 230mA and I have found the issue. I have connected the amp meter wrongly, common to voltage. Here is a picture from my phone showing the actual current. 36.70mA which is reasonable and for the other channel it is 36.66mA. This with the 100,000uF /63v caps connected I have removed the 39,000uf I was afraid they will explode.
We can proceed with the 20H and the 40v transformers right?
I am planning to use these big 220,000uf /50v in the next upgrade. I think it will be extremely awkward for a preamp.
And having the website in the mobile is much easier to share pictures.
I also was wondering why I would have a 230mA and I have found the issue. I have connected the amp meter wrongly, common to voltage. Here is a picture from my phone showing the actual current. 36.70mA which is reasonable and for the other channel it is 36.66mA. This with the 100,000uF /63v caps connected I have removed the 39,000uf I was afraid they will explode.
I am planning to use these big 220,000uf /50v in the next upgrade. I think it will be extremely awkward for a preamp.
And having the website in the mobile is much easier to share pictures.
Hello,
The original poster has left the scene.
I have been exchanging loads of info with him and now he just disappeared.
So no more reasons to add any help here.
Greetings Eduard
The original poster has left the scene.
I have been exchanging loads of info with him and now he just disappeared.
So no more reasons to add any help here.
Greetings Eduard