a friend of mine who is working mostly with russian tubes (well - we can tell that he is an expert in russian tubes) has told me that he has tried that tube in follower type of ciruit to drive some tube and that this tube is really good but it tend to be better with low currents.... So i wouldn't like to drive it to high (say 8-10mA)..... So - my aikido would have 4 pieces of 6n6p per ch - both stages with same current so i can use the same resistors - i have thought to use 470R in both stages as cathode resistor and run it on 220-240V. This would be good I think......
Only problem that I could see with that tube is heater - hungry one I must say.....
oh - by the way this tube is less microphonic than 5687 and also ECC99 - mr. Bas this is for You.
When I have mentioned using it in srpp mode - my friend just smiled and said that this would be interesting ......
....we'll see what comes out 
work work.....
regards
Only problem that I could see with that tube is heater - hungry one I must say.....
oh - by the way this tube is less microphonic than 5687 and also ECC99 - mr. Bas this is for You.
When I have mentioned using it in srpp mode - my friend just smiled and said that this would be interesting ......
....we'll see what comes out work work.....regards
well o.k. Bas - some people like when You call them mr. or mrs. - i was in army and those things where serious matter
I have some jan philips 5687- they are not something special but they are 5687.... i can build aikido with 6n6p an after that with 5687..... this will take a will because of my limited time but i can manage that.... unfortunately i didn't like the sound of the 5687 - it was to much bas in my system in plain common cathode mode.... maybe they will be better in here....
best regards
sunny
I have some jan philips 5687- they are not something special but they are 5687.... i can build aikido with 6n6p an after that with 5687..... this will take a will because of my limited time but i can manage that.... unfortunately i didn't like the sound of the 5687 - it was to much bas in my system in plain common cathode mode....
maybe they will be better in here.... best regards
sunny
Bas - I know that You are on vacation from today.... but maybe You are still reading this thread.... I run on the net on a Raleigh Audio Line Stage - it seems that You have built it also.... Can You evaluate a little bit on both of them (aikido and the Raleigh line).
Thanks...best regards
p.s. i am working on a aikido - when i have something to show i will send a few pic's....
Thanks...best regards
p.s. i am working on a aikido - when i have something to show i will send a few pic's....
chaps
gosh got all serious with the name calling there
in my opinion ecc99 is pants
i've had a pair driving my 5881se for some months now
but replacing a couple months ago
with national 5687
was a bit night and day - 5687 any day
anyway
i have a 300bxls breadboard i have been running
for a year or so now
i have tried many drivers and ecc99 was the worst
these 6n6p are very good and improving as they burn in
i will be incorporating them
into next 300bxls driver
under construction and sounding v.good
my previous linestage was pretty much euridice
we417a or 6c45pi into 5:1 optx
and this aikido
even with ecc88 improves on it
ecc99 is about the worst valve i have tried in it
6n6p is the best
so far
i have set it up as per JBs basic design
it is extremely quiet
extremely stable
extremely well mannered
an extremely open window on the music
bearing in mind i built it one evening
in a fit of boredom
with bits i had lying around
the only differences are:
2uf PIO output caps
power supply is
350-0-350>5z4gt>20H>470uf>1K>470uf>20H>470uf
it sounded slightly better treble with third LC filter
but i needed the choke elsewhere
very happy
dave dove
gosh got all serious with the name calling there
in my opinion ecc99 is pants
i've had a pair driving my 5881se for some months now
but replacing a couple months ago
with national 5687
was a bit night and day - 5687 any day
anyway
i have a 300bxls breadboard i have been running
for a year or so now
i have tried many drivers and ecc99 was the worst
these 6n6p are very good and improving as they burn in
i will be incorporating them
into next 300bxls driver
under construction and sounding v.good
my previous linestage was pretty much euridice
we417a or 6c45pi into 5:1 optx
and this aikido
even with ecc88 improves on it
ecc99 is about the worst valve i have tried in it
6n6p is the best
so far
i have set it up as per JBs basic design
it is extremely quiet
extremely stable
extremely well mannered
an extremely open window on the music
bearing in mind i built it one evening
in a fit of boredom
with bits i had lying around
the only differences are:
2uf PIO output caps
power supply is
350-0-350>5z4gt>20H>470uf>1K>470uf>20H>470uf
it sounded slightly better treble with third LC filter
but i needed the choke elsewhere
very happy
dave dove
currently You have a number of 6n6p offered on e-bay.... but You can also try some russian dilers...... I have mine from a guy from rumania.... unfortunately he had only 4 of them so i would buy them probably on ebay if they work good here in aikido..... they would be used somewhere else also......
regards
sunny
regards
sunny
I have been playing around with a 12FQ7-ECC99 Aikido for a while, and finally tried adding the adjustment of the CF divider resistors according to the Mu per JB's latest article, and adding the "safety" divider at the CF output. Of course, I did both that the same time while I had the unit open (bad me!), and had some interesting results.
Just a summary, I substituted a 120K resistor in place of the lower 100K resistor in the AC divider (Mu=22) to the bottom tubes grid, and used a series pair of 300K resistors for the AC/DC divider at the plate of output of the CF.
Well, I feel that the sound has more meat and lower level detail. Imaging seems to be improved, the unit seems to disappear more. The only problem, is that I now have a buzz in both channels, whereas before the change the circuit was dead quiet. This would mean that the combined change seemed to create a problem with respect to power supply noise, even though the AC signal resolution seemed to improve. I will have to troubleshoot this further, but I thought it was an interesting result.
Things to note, my power supply uses Fairchild "Steath" diodes in a bridge followed by a Schottky in line with the B+ tap. Using a well filtered CLCLC supply.
David
Just a summary, I substituted a 120K resistor in place of the lower 100K resistor in the AC divider (Mu=22) to the bottom tubes grid, and used a series pair of 300K resistors for the AC/DC divider at the plate of output of the CF.
Well, I feel that the sound has more meat and lower level detail. Imaging seems to be improved, the unit seems to disappear more. The only problem, is that I now have a buzz in both channels, whereas before the change the circuit was dead quiet. This would mean that the combined change seemed to create a problem with respect to power supply noise, even though the AC signal resolution seemed to improve. I will have to troubleshoot this further, but I thought it was an interesting result.
Things to note, my power supply uses Fairchild "Steath" diodes in a bridge followed by a Schottky in line with the B+ tap. Using a well filtered CLCLC supply.
David
extra shottky diode
Could you elaborate on what this extra shottky diode does, and would it also be beneficial if you used it with shottky diodes in a bridge configuration? I saw an extra diode in the power supply of one of Jonathan Carr’s preamps but could’t figure out the benefits of this diode – other than maybe increasing the reverse voltage rating?
Thanks in advance.
dmcgown said:
Could you elaborate on what this extra shottky diode does, and would it also be beneficial if you used it with shottky diodes in a bridge configuration? I saw an extra diode in the power supply of one of Jonathan Carr’s preamps but could’t figure out the benefits of this diode – other than maybe increasing the reverse voltage rating?
Thanks in advance.
Guys, I'm new in this thread...
i try to understand about the calculation, but i'm still confusing about how we calculate the cathode resistor for the 1st and 2nd stage...
can someone told me how to calculate that since i tried calculate the resistor in JB's article (Aikido 6n1P and 5687)... they're far from my drawing...
thanks
i try to understand about the calculation, but i'm still confusing about how we calculate the cathode resistor for the 1st and 2nd stage...
can someone told me how to calculate that since i tried calculate the resistor in JB's article (Aikido 6n1P and 5687)... they're far from my drawing...
thanks
Questionable Safety Resistors
Well, I have done some more experimenting with increasing safety divider resistor values on the CF. First, after restoring the dual series 100K AC divider on the CF stage. (i.e. replacing the 120K resistor with the original 100K, I get no noticable decrease in the buzz. I then replaced the 300K series pair of safety resistors with a 1M series pair. The buzz reduced in volume, however was still present. Before introducing the safety resistors, the buzz was barely detectable at the tweeter, with silence at my midrange horns.
Now I am wondering if the safety divider actually feeds PS noise back into the signal after the PS noise cancellation, i.e., increasing the noise. I will have to restore the circuit completely back to the original form to confirm this. What it does tell me is that sims are nice, but real living. breathing circuit is where one finds if the idea actually works.
One idea I have, is some way of removing any AC component in the safety divider, such as a MOSFET current source above the top resistor of the safety divider. There would need to be a resistor value adjustment (trimmer) so that the voltage split can be equalized, Either that, or a choke. The idea is to create a DC only path on the safety divider, with an AC only path for the bottom tube grid divider (by virtue of the series cap).
Well, I have done some more experimenting with increasing safety divider resistor values on the CF. First, after restoring the dual series 100K AC divider on the CF stage. (i.e. replacing the 120K resistor with the original 100K, I get no noticable decrease in the buzz. I then replaced the 300K series pair of safety resistors with a 1M series pair. The buzz reduced in volume, however was still present. Before introducing the safety resistors, the buzz was barely detectable at the tweeter, with silence at my midrange horns.
Now I am wondering if the safety divider actually feeds PS noise back into the signal after the PS noise cancellation, i.e., increasing the noise. I will have to restore the circuit completely back to the original form to confirm this. What it does tell me is that sims are nice, but real living. breathing circuit is where one finds if the idea actually works.
One idea I have, is some way of removing any AC component in the safety divider, such as a MOSFET current source above the top resistor of the safety divider. There would need to be a resistor value adjustment (trimmer) so that the voltage split can be equalized, Either that, or a choke. The idea is to create a DC only path on the safety divider, with an AC only path for the bottom tube grid divider (by virtue of the series cap).
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