Re: PLAYING WITH CAPS
It seems that TL used a higher voltage transformer than needed so he bleeds in order to lower the B+ (?). In any case it appears that a bleeder is needed anyway to avoid voltage build-up before the valves start conducting.
fdegrove said:
It seems that TL used a higher voltage transformer than needed so he bleeds in order to lower the B+ (?). In any case it appears that a bleeder is needed anyway to avoid voltage build-up before the valves start conducting.
BLEEDER.
Hi,
In this case it will perform two functions:
It will allow for a slightly slower ramp up of B+ and keep it within limits.
Also,and that is the main function of the bleeder resistor in general:it will discharge the PSU caps when the unit is turned off.
As it is there I find it rather ridiculous (unless it is a typo).
Even if it is only used to bleed off excessive voltage on the B+ there are more elegant and useful ways to do this.
All in all an interesting circuit idea and an elegant solution...too bad OPTs are so expensive.
Cheers,😉
Hi,
In this case it will perform two functions:
It will allow for a slightly slower ramp up of B+ and keep it within limits.
Also,and that is the main function of the bleeder resistor in general:it will discharge the PSU caps when the unit is turned off.
As it is there I find it rather ridiculous (unless it is a typo).
Even if it is only used to bleed off excessive voltage on the B+ there are more elegant and useful ways to do this.
All in all an interesting circuit idea and an elegant solution...too bad OPTs are so expensive.
Cheers,😉
5Y3GT
Hi,
For the Euridice PSU:
5Y3GT DATA
Please note the 50V drop when 125mA is drawn and a max. input C of 32 mF.
Cheers,😉
Hi,
For the Euridice PSU:
5Y3GT DATA
Please note the 50V drop when 125mA is drawn and a max. input C of 32 mF.
Cheers,😉
Thanks Frank for your help.
Coming back to the B+ cap it seems that the oil cap that I added is the culprit to the problems mentioned. The preamp does have bass the thing is that lacks impact (rounded bass) and obscures the rest of the spectum, music now has a heavy presentation.
This cap is no good for this position, well in any case this type of caps is intended for power factor correction on mains lines, its rated at 380VAC. Will try now a Solen cap of 15uf.
Nice to have you around. What are you up to? Any preamp on the oven?
Coming back to the B+ cap it seems that the oil cap that I added is the culprit to the problems mentioned. The preamp does have bass the thing is that lacks impact (rounded bass) and obscures the rest of the spectum, music now has a heavy presentation.
This cap is no good for this position, well in any case this type of caps is intended for power factor correction on mains lines, its rated at 380VAC. Will try now a Solen cap of 15uf.
Nice to have you around. What are you up to? Any preamp on the oven?
B+ Caps
Frank,
Yesterday i removed the oil caps and installed the 15u Solens (old style, with alu cans instead of the regular plastic cases).
The sound really improved (the effect is like testing output cap) but highs are not specialy dramatic, subdued actually, so could still be improved. The total 20u seems enough.
I'm thinking on adding 10u Axon's to the 5.6u already in place instead of the 15u Solen.
Every change on this cap really makes a big difference.
Which would be your choice of cap for this position? 😕
Frank,
Yesterday i removed the oil caps and installed the 15u Solens (old style, with alu cans instead of the regular plastic cases).
The sound really improved (the effect is like testing output cap) but highs are not specialy dramatic, subdued actually, so could still be improved. The total 20u seems enough.
I'm thinking on adding 10u Axon's to the 5.6u already in place instead of the 15u Solen.
Every change on this cap really makes a big difference.
Which would be your choice of cap for this position? 😕
CAPS
Hi,
Yes,that is to be expected.
Only you can be the final judge on this as far as your circuit is concerned.
What I can suggest though is bypassing the higher values of polyprops with smaller ones of equal or better quality.
For instance,bypass a 10 or 20 mF MKP cap with a 0.100 mF MKP and a 0.010 mF MKP.
Cheers,😉
Hi,
Yes,that is to be expected.
Only you can be the final judge on this as far as your circuit is concerned.
What I can suggest though is bypassing the higher values of polyprops with smaller ones of equal or better quality.
For instance,bypass a 10 or 20 mF MKP cap with a 0.100 mF MKP and a 0.010 mF MKP.
Cheers,😉
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