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Debugging my Aikido

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It's .01sec/div.
So with my scope I would have to set it to 10m and then X10 ?

If I do that I get roughly one wave on my display!

The scope is a Tektronix T921
The trigger should be set to internal, or to X input if the external trigger signal is used.
Ok..I had it on there but now I understand why it is there! :)

Thanx Milan..
 
I don't know why..maybe because I've set the scope according to moamps...but now at least a part of the puzzle is falling into place.

If I measure now before the cap the sine wave is exactly the same as after the cap....!!!!

I've compared both channels with each other...I now seem to be able to test ripple on the b+ ...which I could not do before on the milliamp level....

all measurements are exactly the same except on pin 6 where the one channel is quiet and the other has one has hum..

b+ of 10mV peak to peak is not too bad is it? The ripple on the output looks to be around 1/2 that of the b+ ripple.
 
Bas Horneman said:
B I N G O !!!!!

Don't know why I did not spot it before... the other 100k resistor was connected to pin 6 instead of 7...

That type of thing is sometimes the hardest to spot! You check all the solder joints and they are OK. You check all the component values and they are all OK also. Next you look for grounding issues and all is fine. But one component with one end connected to the wrong place... :xeye:

All I can say is I've been there and probably will be again. Glad you found the problem!
 
It is really for us to guess why it HUMs when the connections are made wrong. We can only think of things with all components in the correct position.

Anyway, we all learn a lesson to double and triple check the connections when we have a problem.

Johnny
 
Hi, question -

how does aikido sound in Your setup?
I am on the half way to build one but still thinking about the input tube...... I need 8-12 total gain. I might go after 6n14p (russian) and at the output 6n6p (russian).
Another question that bothers me so mr. Bas could probably answer it - did You use on tube for srpp for the each channel or did You use upper triodes as one tube (and use it for both ch) and lower triodes as the other tube (for both ch.). Also the same with the output tubes.....?
thanks - best regards
 
Hallo Sunrise,

For both tubes I used one for upper and lower tube on each channel..for example...one 12sn7 for the left channel doing the top and bottom triode.

And it sounds real good in my setup. Bass is amazing and turning up the volume it just stays "in control" enabling my system to play a lot louder than my other excellent line stage the RA "Mood Indigo".

Regards,
Bas
 
sunrise said:
thnx for the reply - i have an information that some tube types (like 6n6p, 6n14p - russian) are not very well paired inside one glass tube...... this mean that I have to pair them - or minor non-similarities in one tube would be o.k. if You know what i mean.
sorry for my english....


nobody replied :confused:
- i gues that I would have to try to connect it upper tube (left and right), lower tube (left and right)
i will try to make it with 4 pieces of 6n6p (russian - running at 8-10mA) - will see how it works.... :)

Any objection about that approach ?!:hot:

also - when trying to decide how to connect everything the best way - i have stumbled on one thing all over again..... how to connect that second stage the best and the shortest way? when wiring point 2 point - no problem with srpp and also no problem with follower but connecting them together gives me a headacke(?).... those wires simply have to be a little longer ?! is this a problem....?:confused:
best regards
 
sunrise

bas did answer you
use one valve for each
totem pole (top and bottom)

if you buy by the handful

(i just got 12 x 6n1p
for $20US inc postage
and 8 x 6n6p for same
that's 4 aikido linestages
for $40US
that's good....)

the way to find the best
is to build the circuit
as john broskie says

then

measure Va bottom triode
if this is half HT (B+)
you've got a good valve
use the closest you can
it'll still sound good

what's this 6n14p?


i will also try
an all 6n6p one
just to see

looking forward

dave dove

don't worry too much
about the wiring ;)
 
Dear Dave,
thanks for the reply - yes I know that Bas repied me but he said how he used tubes in his preamp...... I was asking if the non simetry between the trides in one envelope would be a problem since some russian tubes are not very well paired inside the envelope and also - i like my upper tube to have its heater on a pottential and my lower tube to have its heater to the ground..... In this way You might have a problem because mr. Broskie said to use one tube for srpp and another for follower; the same the other channel. It is interesting that it works nicely after all.....
I don't now maybe I am to ...... something ....:( I think that I should better get to work than talk.:smash:

6n14p is a russian dublew triode that people don't use often - i don't know why - it has mu of arround 25 - that is total gain of 12,5 in aikido - that is what I would like - You will find the datasheets of this tube on Frank's Electron tube Pages (nice tube) - also I willl try try to see how 6n6p would work in srpp here - but on low currents - say arround 5-10mA....:D - it is a rahter big tube - but I think that it might be interesting to hear it here..... hope that everything will work first time and o.k. - don't have much tubes to pair them :dead:
will keep You informed of course... :)

thanks for the wiring reply :)
 
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