Thank you Salas
Now I have another question regarding the TX.
I am not very sure about the best ~voltage to use.
From post 758 http://www.diyaudio.com/forums/showthread.php?postid=1723989#post1723989 I understand that For 33Vdc use either 28Vac or 30Vac.
After rectifying I will have 41Vdc and you wrote there is no problem because the excess will be handled as heat.
I know that electronic circuits do not like heat so my question is: What are the benefits for using a higher voltage and if there are no advantages, what TX voltage would be the best choice ?
Best regards
Ricardo
Now I have another question regarding the TX.
I am not very sure about the best ~voltage to use.
From post 758 http://www.diyaudio.com/forums/showthread.php?postid=1723989#post1723989 I understand that For 33Vdc use either 28Vac or 30Vac.
After rectifying I will have 41Vdc and you wrote there is no problem because the excess will be handled as heat.
I know that electronic circuits do not like heat so my question is: What are the benefits for using a higher voltage and if there are no advantages, what TX voltage would be the best choice ?
Best regards
Ricardo
35-41VDC will be OK. You just win a better margin for possible mains AC drop for around 40VDC. No more, bcs Q2 is going to be in danger if the mains stay higher than nominal some times. But don't think that the ACX1.41 calculation is going to hold with 200mA constant current if with 50VA trafo. Rather X1.33. So you gonna be fine.
Thank you again Salas
I will order a 2x15Vac 50VA TX and wire it to produce 30Vac.
After rectification it will produce around 40Vdc.
Now about the output cap, I like BG sound but I can not find any 470u 40v BG so I wonder if a 680uF BGNx 35V would be suitable.
I experimented with 470u BG FK 16V on my 101 na d replaced them by 680uF 35v BGNx and the difference is abismal.
(So much better bass and lower noise I could not believe it).
If not, can you suggest a good cap for the output ?
Regards
Ricardo
I will order a 2x15Vac 50VA TX and wire it to produce 30Vac.
After rectification it will produce around 40Vdc.
Now about the output cap, I like BG sound but I can not find any 470u 40v BG so I wonder if a 680uF BGNx 35V would be suitable.
I experimented with 470u BG FK 16V on my 101 na d replaced them by 680uF 35v BGNx and the difference is abismal.
(So much better bass and lower noise I could not believe it).If not, can you suggest a good cap for the output ?
Regards
Ricardo
A shootout would be interesting! 
nicoch46 said:
Perhaps in two years time I will hear the difference too
Now, I don't hear the difference between different resistors, but I'll take your word for it and try the fancier resistors.
I think I'll stay away from the expensive Vishay bulk foil resistors for now, but I got this idea, and you can call me crazy if you want. I'll wind my own resistors (as an experiment) from evanohm wire. They use evanohm in high precision resistors and fancy measuring equipment... or at least they did some years back.
ikoflexer said:
Perhaps in two years time I will hear the difference too
Now, I don't hear the difference between different resistors, but I'll take your word for it and try the fancier resistors.
I think I'll stay away from the expensive Vishay bulk foil resistors for now, but I got this idea, and you can call me crazy if you want. I'll wind my own resistors (as an experiment) from evanohm wire. They use evanohm in high precision resistors and fancy measuring equipment... or at least they did some years back.
Do the Russian PIO//10% Russian Teflon for interstage and 100nPIO//your current Cout first. Rload and 47K series next.
ikoflexer said:
Perhaps in two years time I will hear the difference too
nicoch46 said:I dont have caps on signal path , if you have better go for caps
and TT+cartidge
Nicoch is right, first things first. If you will not hear the caps you will not hear the resistors either. But don't underestimate your hearing. Jonners heard, Lee heard, Nicoch hears, this is not an international conspiracy, we never met each other!
RCruz said:Just built a rig to measure the led´s dropout...
I have got 6.36Vdrop so I can use 14r on R1 to be near 211mA ICCS and 4.8W to dissipate. Can I use light alu sinks bolted to the mosfets ?
Now I know how to focus the shunt
Ricardo
I think that 15R is the standard value. Off course it will work. Its dissipation is going to be 0.6W so better use a 2W part for good reliability in the long term. Better use a heavier heatsink, good for 10W, especially bcs Iko has put em close together.
I have a buzzing sound that's driving me nuts. Not hum, but a buzzzzz. It only happens with the psu. Tried it with batteries and the preamp is quiet. Tried changing the grounding scheme, different transformers (EI, torroid), a totally different psu, still, the buzzing is there. Guess I'm just venting some frustration.
What's your psu like, before the regulator?
What's your psu like, before the regulator?
humm...
>try long wire just to see if are trafo (twist all cable)
>disconnect the main heart , if is this put two diode reversed with ntc like Pass
>try with/out rca output gnd style
my are simple, rfi filter- tx-diode-4700uf-0,1bypass
>put a sheet alu under the phono pcb connect to gnd to shield
>put 0.1uf at input B+ phono
>if you have one psu disconnect one channel from b+
>what gnd use your TT ?
>disconnect the TT motor
> try different pre or connect to amp
>try long wire just to see if are trafo (twist all cable)
>disconnect the main heart , if is this put two diode reversed with ntc like Pass
>try with/out rca output gnd style
my are simple, rfi filter- tx-diode-4700uf-0,1bypass
>put a sheet alu under the phono pcb connect to gnd to shield
>put 0.1uf at input B+ phono
>if you have one psu disconnect one channel from b+
>what gnd use your TT ?
>disconnect the TT motor
> try different pre or connect to amp