Yes its OK. Bib must not take more than 36VAC transformer for its 2SK117 in CCS tail to stay under max VDS voltage spec.
The 2x18 in series coils you will use with Bib. Does not lose voltage, its very efficient. To the contrary they give more than nominal secondary on 230VAC mains, all those ''French'' ones I had used.
Well. One step at time. First of all I will start building the Pre according your scheme. Because I'm, still waiting for the kit.
As you said, I'm a beginner, but also patient and I like to read. Abut the bugs on the kit, well... I'll see at the moment and try to solve them. Not by my own, but "with a little help of my friends".
As you said, I'm a beginner, but also patient and I like to read. Abut the bugs on the kit, well... I'll see at the moment and try to solve them. Not by my own, but "with a little help of my friends".
I suppose that the separate source resistor R2/R18 are for better match the jfet Q3/4 ...
with perfect match I can use one 5,1ohm ? what type resistor use for this ones?
there are tree 1Meg resistor one on Riaa what use ?
thanks !
As always no shinkoh no party
with perfect match I can use one 5,1ohm ? what type resistor use for this ones?
there are tree 1Meg resistor one on Riaa what use ?
thanks !
As always no shinkoh no party
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Better use two separated resistors, one for each input jfet source.
Use low ppm resistors because source resistors tend to add noise, particularly in the first stage.
R19 (1M) is paralel with R4 (6k8) so it results in 6754r
C2 is 0.047uF so 6754 x 0.047 = 317.4uS (Almost a perfect match to the needed 318uS)
R5 (1M) is the gate resistor for second stage jfet Q5
R8 (1M) is there to discharge the output cap on power off.
Use low ppm resistors because source resistors tend to add noise, particularly in the first stage.
R19 (1M) is paralel with R4 (6k8) so it results in 6754r
C2 is 0.047uF so 6754 x 0.047 = 317.4uS (Almost a perfect match to the needed 318uS)
R5 (1M) is the gate resistor for second stage jfet Q5
R8 (1M) is there to discharge the output cap on power off.
Sorry I start remember ....318.2 max tollerance ? better up or down?
PS
R19 thinking on tollerance of R4 ...is quite optional ,I have a 12 mkp1837 10 nf 5% only one is up, five 0% ,one 7% the other 2/3/5% with the 1% caps I see simple 0% goal...
theR8 (1M) the discharge r can be avoid .....yes ?
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The Riaa curve has three inflexion points:
50.05Hz <=> 3180uS
500.5Hz <=> 318uS
2122Hz <=> 75uS
IMO the middle one is really important.
If you do not use R19, and R4 is 6k8, then 6800 x 0.047 = 320uS very far from 318uS
The output bleeder is very important because the output cap keeps it´s charge after power off.
If you omit it, you will hear loud noises when powering up your power amp.
PS: Use a good DMM to measure all resistors and caps... avoid believing what is writen on the parts.
Of course you might get lucky.... The majority of the 6k8 kiwames that I use, measure 6750r so I do not need to use the // 1M.
I prefer to trim the 47nF cap with smaller values to get the better 318uS. I also do rely a lot on severall people listening pannels.
50.05Hz <=> 3180uS
500.5Hz <=> 318uS
2122Hz <=> 75uS
IMO the middle one is really important.
If you do not use R19, and R4 is 6k8, then 6800 x 0.047 = 320uS very far from 318uS
The output bleeder is very important because the output cap keeps it´s charge after power off.
If you omit it, you will hear loud noises when powering up your power amp.
PS: Use a good DMM to measure all resistors and caps... avoid believing what is writen on the parts.
Of course you might get lucky.... The majority of the 6k8 kiwames that I use, measure 6750r so I do not need to use the // 1M.
I prefer to trim the 47nF cap with smaller values to get the better 318uS. I also do rely a lot on severall people listening pannels.
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I suppose that the separate source resistor R2/R18 are for better match the jfet Q3/4 ...
with perfect match I can use one 5,1ohm ? what type resistor use for this ones?
there are tree 1Meg resistor one on Riaa what use ?
thanks !
As always no shinkoh no party
R2/R18 are essentially in parallel. If using one common, it should be 1.5R not 5.1R. The other questions have been discussed already as I see above.