after 1K gate resistor of first buffer- practically from gates to gnd
calc 1k and cap for, say, 100KHz
ok, that'll be 1n6
you can change 1K , 5-times up ........ so 5K1 , then use 330p
though, I'm not so sure that you need it ........
if you find that intrusive, we can put RC in parallel with anode resistor
calc 1k and cap for, say, 100KHz
ok, that'll be 1n6
you can change 1K , 5-times up ........ so 5K1 , then use 330p
though, I'm not so sure that you need it ........
if you find that intrusive, we can put RC in parallel with anode resistor
So I will add it across the 221k to ground.
I may need it cause some sources sounded shrilled and pitchy
Thanks zenmod
I may need it cause some sources sounded shrilled and pitchy
Thanks zenmod
There was a perceptible difference in the sound after I added the 0.1uf cap across the zener (in parallel). I won't say what the difference is as I want to know what others sense or otherwise. I prefer what I hear with the cap in place.
Mr Pass, is there anything negative that could arise from doing what I have? Amp is left ON all the time.
Mr Pass, is there anything negative that could arise from doing what I have? Amp is left ON all the time.
Has someone built the preamplifier with 2SK170?
what value for R1 should be used?
what differences in sound are there?
Thank you
what value for R1 should be used?
what differences in sound are there?
Thank you
If you have a distortion analyzer with which to measure thd vs bias
then life is easy. Just use a bias resistor to set the constant current
source to somewhat less than the Idss of the follower and then use the
distortion analyzer to set the bias voltage.
If you need to adjust the distortion via the DC output of the follower,
you want to operate the follower at Idss so that you can measure the
DC at the source and use the chart. In this case, the constant current
source should deliver at the Idss of the follower. If the CCS and follower
transistor are matched, then the value of the resistor is 0 and you need
only be certain that the Idss is not too high, say <10mA.
then life is easy. Just use a bias resistor to set the constant current
source to somewhat less than the Idss of the follower and then use the
distortion analyzer to set the bias voltage.
If you need to adjust the distortion via the DC output of the follower,
you want to operate the follower at Idss so that you can measure the
DC at the source and use the chart. In this case, the constant current
source should deliver at the Idss of the follower. If the CCS and follower
transistor are matched, then the value of the resistor is 0 and you need
only be certain that the Idss is not too high, say <10mA.
Hi,
I know some are already using the UltraBiB with the B1 Nutube, but I thought I would post of an issue I had with the combo. I built the UltraBiB in an external chassis. I powered it up, then powered up the B1. Powering up the B1 would immediately take out Q2 on the UltraBiB. Maybe this wouldn't have happened if I left the B1 switch on so they would both power up at the same time, but I didn't experiment because I was running short of the BC560Cs.
In any event, Salas suggested installing a diode rated 1 amp between the drain (pin 2) of regulator M1 and the positive side of capacitor C1 on the UltraBiB, with the cathode of the diode pointing toward C1. That solved the issue.
Alan
as a major rule, I would suggest - if you're going to trouble assembling proper reg, that same reg is placed locally with stage, not in separate enclosure
also , sequencing powering up of one component ( preamp in this case) is recipe for trouble, even without major ookup of components going south, one can expect nasty buzzes on output
tricky in (hopefully) rare occasions when power amp is powered prior to preceding stage
also , sequencing powering up of one component ( preamp in this case) is recipe for trouble, even without major ookup of components going south, one can expect nasty buzzes on output
tricky in (hopefully) rare occasions when power amp is powered prior to preceding stage
I originally built the B1 Korg from the kit. The chassis is too small for a power supply. This is currently an experiment. I could do that if I thought the sound worthy of a bigger chassis. The UBiB has very stable voltage after 30 minutes, but runs high before then, so it doesn't seem to be a bad thing to keep the power supply on and stable while being able to turn off the Korg. I don't know what kind of tube life the Nutube has.
The Nutube from recollection is claimed to have a 30 000 Hour Life ?
My thoughts on this as I have become keen on the KB1, has been how long does the Nutube require to be working at its optimum, i.e, Does it have a Burn In Period ?
The KB1 I am using at present has improved in the delivery over the time I am using it, from being a '0 Hours' off the bench build to having about '40 Hours' of usage.
My thoughts on this as I have become keen on the KB1, has been how long does the Nutube require to be working at its optimum, i.e, Does it have a Burn In Period ?
The KB1 I am using at present has improved in the delivery over the time I am using it, from being a '0 Hours' off the bench build to having about '40 Hours' of usage.
practically , if your goal is 24Vdc , you can ignore (sloooow) changes if you're in bracket of 23-25Vdc
Hello everyone,
I recently purchased a B1 from a fellow forum member and couldn't be happier. I am running a Threshold S-500 amp into a pair of Triangle speakers.
Now recently I decided to swap out the electrolytic caps with some film caps. For that process i plugged my old preamp back into my system and since the B1 is phase reversing in changed the polarity back to normal (speaker cable - plus to plus minus to minus).
When I was done swapping the caps i put the B1 back in the system and I was amazed! It is really hard to describe it but somehow it sounded more cohesive like everything clicked. "Man those caps make a huge difference" I thought. After a while it came back to me that I forgot to change back the speaker cables, so I did expecting to be blown away even more. I was not. I 100% prefer the sound with the speaker cable in "correct" phase.
Did anyone of you had the same experience? Am I crazy? I am pretty new to this hobby so I don't really know what reversing the polarity does to the sound. Maybe someone can explain to me what exactly I am hearing that I find so pleasant 😀
Best regards
I recently purchased a B1 from a fellow forum member and couldn't be happier. I am running a Threshold S-500 amp into a pair of Triangle speakers.
Now recently I decided to swap out the electrolytic caps with some film caps. For that process i plugged my old preamp back into my system and since the B1 is phase reversing in changed the polarity back to normal (speaker cable - plus to plus minus to minus).
When I was done swapping the caps i put the B1 back in the system and I was amazed! It is really hard to describe it but somehow it sounded more cohesive like everything clicked. "Man those caps make a huge difference" I thought. After a while it came back to me that I forgot to change back the speaker cables, so I did expecting to be blown away even more. I was not. I 100% prefer the sound with the speaker cable in "correct" phase.
Did anyone of you had the same experience? Am I crazy? I am pretty new to this hobby so I don't really know what reversing the polarity does to the sound. Maybe someone can explain to me what exactly I am hearing that I find so pleasant 😀
Best regards
flipping phase of dominant (in this case second) harmonic
that phase is matter of personal preference, so leave it in polarity which you prefer
that phase is matter of personal preference, so leave it in polarity which you prefer
It is possible that another device in the chain inverts the absolute phase, it can even be the case for certain recordings which are in reversed phase: therefore inverting the absolute phase twice in a row does not mean inverting the phase ...
Gidu
My own experience is a bit simpler, but similar: My usual pre-amp is a Pass XP-20 (list $7000 or so?) and I've been listening recently to a balanced B1 against it. I don't know which I prefer, but it is amazingly how close they are. And the B1 cost about $200 for parts?
I dont think one of my components is reverting phase.. otherwise I would have been listening out of phase for forever