Re: How to reduce the gain of my Aikido
Leave pot at 50K. You should drive the power tube directly with Aikido preamp for best results.
ollebolle said:Tjenare Karsten!
There will be more pictures when I come home!
Yes, the hum was reduced, not gone!
And yes, I forgot the capacitor
I will try It right away when I come home! It might do the trick!
About the design: You described it very well!
The chassis is an old printer switch, which I modified a bit. From the beginning the sides was made of plastic...
The power transformer and the choke is taken from old radio gear from the 50's and 60's.
So is the knobs on the front side.
Do you know how I got the handle bars? I bought them cheap at IKEA.
It was a real coincidence i found them! I was walking by the kitchen section, and saw these.
They are normally mounted at kitchen doors, but I thought the suited my new amp!
This is my philosophy! DIY is great fun and doesn't have to be expensive!
This is the coolest printer switch I know!
sonata149 said:
Leave pot at 50K. You should drive the power tube directly with Aikido preamp for best results.
Hats off to JB!
Just got my Aikido 5687 kit today and WOW.
Superb quality. All the caps included, etc. Some NOS 6X5 rectifiers from tubesandmore also.
I am very impressed.
Also Bas's psu from Gregg in Canada.
So I'll be joining you Ollebolle with the questions very soon.
Nice work so far by the way.
Cheers
Just got my Aikido 5687 kit today and WOW.
Superb quality. All the caps included, etc. Some NOS 6X5 rectifiers from tubesandmore also.
I am very impressed.
Also Bas's psu from Gregg in Canada.
So I'll be joining you Ollebolle with the questions very soon.
Nice work so far by the way.
Cheers
Unfortunately one 5687 tube is broken, so I'm waiting for a new one.
I was lifting it out of it's socket, and it just broke. It might have been tensions in the glass, I don't really know why it broke...
But I know a guy here in Sweden who can get me a new one
So I will have to wait a week or so...
I was lifting it out of it's socket, and it just broke. It might have been tensions in the glass, I don't really know why it broke...
But I know a guy here in Sweden who can get me a new one
So I will have to wait a week or so...
That's a shame. Frustrating when you have to wait for items and you can't buy them locally.
I still need to buy 2 x 5687 tubes. I have 4 x 6N1P for the input tubes but nothing else.
Mind you I have plenty of time because I haven't started building anything yet.
Still confused with what transformer I need in regards to the windings and voltages.
I'm going for DC heaters.
New builder
Hello Gentlemen,
I am getting the parts and my thoughts together to build a pt-2-pt Aikido preamp. This thread has answered most of my questions and I was impressed with some of the grounding ideas. I have a couple of uncertainties remaining and I'd like to ask a few questions.
I have a plethora of 6N1Ps and so I had planned to use four on this project. I notice, however, that few people use the same type of twin triode for the two stages. What am I missing? Why not use the same tube types?
In Broskie's table of resistor values printed in the PCB manual, the numbers for the 6N1Ps differ from the 430 ohm values in his original article. I have tried interpolating the values and I have read about running the second stage tubes hotter than the first stage but I have not made sense of it. I would think that the values are important as they determine the current. I could use some enlightenment on this subject.
I have a power supply with 6.3 vac taps that I would ordinarily use for the heaters, however most builders seem to prefer relatively complicated DC power supplies. I've heard some pretty quiet amps running with AC heaters. Does DC heater power really lower noise that much?
Thanks for the assistance
Hello Gentlemen,
I am getting the parts and my thoughts together to build a pt-2-pt Aikido preamp. This thread has answered most of my questions and I was impressed with some of the grounding ideas. I have a couple of uncertainties remaining and I'd like to ask a few questions.
I have a plethora of 6N1Ps and so I had planned to use four on this project. I notice, however, that few people use the same type of twin triode for the two stages. What am I missing? Why not use the same tube types?
In Broskie's table of resistor values printed in the PCB manual, the numbers for the 6N1Ps differ from the 430 ohm values in his original article. I have tried interpolating the values and I have read about running the second stage tubes hotter than the first stage but I have not made sense of it. I would think that the values are important as they determine the current. I could use some enlightenment on this subject.
I have a power supply with 6.3 vac taps that I would ordinarily use for the heaters, however most builders seem to prefer relatively complicated DC power supplies. I've heard some pretty quiet amps running with AC heaters. Does DC heater power really lower noise that much?
Thanks for the assistance
Hi Capt Dave!
As I see it the different values is a matter of how hot the tubes are driven. In the article you mention (6N1P together with a 5687 and B+ of 220 V, right?) the resistors are 430 Ohm.
In the Rev. A schematic on Tubecad.com there are more values to choose from. These values depend on the B+ and how hot you want to run the specific tube. AFAIK, a tube sounds better if you run it relatively hot, however, the life time of the tube will be shortened (how much I don´t know but I do not think it is "dramatically").
As you know, Broskie is constantly fine-tuning his Aikido-circuit making it better / more flexible, which is a nice thing I think.
As I see it Broskie has decided to go out with values for running the 6N6P hotter than in the original shown article.
If I were you I would stick with the values shown on Tubecad.com. The values shown here (Rev. A) are the same as the values in my Rev. B - and might be the same in Rev. C (the newest edition). Please remember that the newest editions have no major changes for the original circuit. Most of the changes are made to make the circuit / PCB more flexible (more different tubes can be used).
Regarding AC or DC for heaters. This is difficult. Some say that AC sounds the best and som say that DC is the most quite. I can not say for sure. However, as I see it most guitar amps are running their heaters with AC and most (?) HiFi-amps are running the heaters with DC.
Running the heaters with AC is fast and cheap. You can connect your 6,3 / 12,6 V windings directly to your tube. This is easy and you do not need rectifiers, chokes and capacitors. At the end you also end-up with an amp which is a little lighter on the weight. OK, I think it is most common to use small, "simple" regulators of the LM317 type (LM350, LT1085 etc.) for the heaters if you want to go for DC.
Hope this helps.
Karsten
As I see it the different values is a matter of how hot the tubes are driven. In the article you mention (6N1P together with a 5687 and B+ of 220 V, right?) the resistors are 430 Ohm.
In the Rev. A schematic on Tubecad.com there are more values to choose from. These values depend on the B+ and how hot you want to run the specific tube. AFAIK, a tube sounds better if you run it relatively hot, however, the life time of the tube will be shortened (how much I don´t know but I do not think it is "dramatically").
As you know, Broskie is constantly fine-tuning his Aikido-circuit making it better / more flexible, which is a nice thing I think.
As I see it Broskie has decided to go out with values for running the 6N6P hotter than in the original shown article.
If I were you I would stick with the values shown on Tubecad.com. The values shown here (Rev. A) are the same as the values in my Rev. B - and might be the same in Rev. C (the newest edition). Please remember that the newest editions have no major changes for the original circuit. Most of the changes are made to make the circuit / PCB more flexible (more different tubes can be used).
Regarding AC or DC for heaters. This is difficult. Some say that AC sounds the best and som say that DC is the most quite. I can not say for sure. However, as I see it most guitar amps are running their heaters with AC and most (?) HiFi-amps are running the heaters with DC.
Running the heaters with AC is fast and cheap. You can connect your 6,3 / 12,6 V windings directly to your tube. This is easy and you do not need rectifiers, chokes and capacitors. At the end you also end-up with an amp which is a little lighter on the weight. OK, I think it is most common to use small, "simple" regulators of the LM317 type (LM350, LT1085 etc.) for the heaters if you want to go for DC.
Hope this helps.
Karsten
I don't know if this helps or not but here goes. I built my first Aikido and used both the 9 pin boards and the 6X5 power supply board that was available here at this site before John went into production on his Aikido boards.
The power supply board documentation can be found at Http://basaudio.net/diyhosting/myown/diyaudio/aikido_pcb/aikido_psu_v1.gif
It shows a easy to build power supply complete with heater bias.
The 6N1p input tube along with the 5687 output will provide flawless results. The 220V B+ works fine with this tube combo and the 6FQ7/5687 combination.
The power supply board documentation can be found at Http://basaudio.net/diyhosting/myown/diyaudio/aikido_pcb/aikido_psu_v1.gif
It shows a easy to build power supply complete with heater bias.
The 6N1p input tube along with the 5687 output will provide flawless results. The 220V B+ works fine with this tube combo and the 6FQ7/5687 combination.
I was building mine, p-to-p, about the same time burnedfingers was building his. I've since moved on to 6bk7b driving 7044 outputs with no changes to resistor values from the original 220v schematic. Moves things up another notch for me.
I'm using a 12vdc regulated supply. It is dead silent. It is much like the PS boards that John Broskie is now selling on the site. I'll be using them on my next version.
I'm using a 12vdc regulated supply. It is dead silent. It is much like the PS boards that John Broskie is now selling on the site. I'll be using them on my next version.
Thanks for all the good ideas. I'd still like to hear about using a set of four tubes of the same type rather than two differing pair.
I had a ephifany today concerning the heater power supply. I have a 19 volt laptop power supply rated at 3.5 amps at 19 volts that is just collecting dust. Since 19 is (within a tenth) a multiple of 6.3, I considered paralleling a couple of tubes in series with the other two for 19 volts. I scoped it and found the supply to be very high quality. At the .01 volt scale I can't identify any wave form whatsoever. It should be very satisfactory.
Now I just need to drag up a power transformer.
I had a ephifany today concerning the heater power supply. I have a 19 volt laptop power supply rated at 3.5 amps at 19 volts that is just collecting dust. Since 19 is (within a tenth) a multiple of 6.3, I considered paralleling a couple of tubes in series with the other two for 19 volts. I scoped it and found the supply to be very high quality. At the .01 volt scale I can't identify any wave form whatsoever. It should be very satisfactory.
Now I just need to drag up a power transformer.
Now I have got new tubes!
I promised some new pictures! Here they are:
I used my aikido, my tube amp, and my B&W 802 Matrix speakers.
Mercy, mercy mercy with Cannonball Adderley Quintet. Great stuff!
My tube amplifier. It's a RH84, EL84SE. I like it!
You may think I have the wrong speakers for small tube amps, but I'm working on some transistor-amps too
I promised some new pictures! Here they are:
I used my aikido, my tube amp, and my B&W 802 Matrix speakers.
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Mercy, mercy mercy with Cannonball Adderley Quintet. Great stuff!
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An externally hosted image should be here but it was not working when we last tested it.
My tube amplifier. It's a RH84, EL84SE. I like it!
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You may think I have the wrong speakers for small tube amps, but I'm working on some transistor-amps too
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I can't help but notice that you only have a 2 pronged power lead - Have you got your case grounded - really you need a 3 pronged lead with the case grounded to mains/safety earth. To do otherwise is a bit risky......
I don't know what the safety code is where you live, but regardless, i would be earthing that case. Usually then circuit ground is brought to one point (ie star) and then that star point is tied to the chassis earth vis a pair of back to back diodes paralleled with a 0.01uf cap and a 5 or 7W 10R resistor. All of these components to have a high enough rating to withstand the B+ voltage.
Maybe you have all this done, but thought I'd say it just in case....
Fran
I don't know what the safety code is where you live, but regardless, i would be earthing that case. Usually then circuit ground is brought to one point (ie star) and then that star point is tied to the chassis earth vis a pair of back to back diodes paralleled with a 0.01uf cap and a 5 or 7W 10R resistor. All of these components to have a high enough rating to withstand the B+ voltage.
Maybe you have all this done, but thought I'd say it just in case....
Fran
About the hum, it's still there, and I can hear
AC heaters should not be the problem as long as you have twisted the wires and routed them away from signal leads...
My MJ headphone amp is as quiet as my other tube amps using DC heaters.
I am quite positive that you have a ground loop somewhere...
I was struggling with a bit of hum in my first headphone amp for 6 months until I found out that I had connected the shield of the input wires on both sides...
It is so easy to overlook something small...and you will notice that your Aikido will sound much better without residual hum.
I have also built an Aikido headphone amp that is pretty much the quietest piece of equipment I ever had (using DC heaters).
PS. woodturner-fran is right...get that thing properly earthed in case it is not.
more PS. nice speakers!!
Yes, the speakers sounds good! They are not DIY, but I think I will keep them anyway
The grounding is completely redone since that picture. The glue is just to keep the cables in place...
Fran: I think I will try your ground-breaking circuit!
And, yes the chassis is not grounded, and I know it can be dangerous if the AC gets in touch with the metal chassis.
But after the transformer I am separated from earth, and it's less dangerous.
The fact is, I don't have grounded AC wall outlets in my listening room
There are grounded outlets in the kitchen though.
We have 230V 50Hz here in Sweden by the way...
I will deal with this later. Until then I will be careful... I have a friend working as an electrician. Soon his learning-time will be out and he will get his certificate. Mabye he and I will install real grounded outlets later
I will look into the Aikido as soon as I get time!
ps. Thank you for your support guys! It's great fun building stuff when you get support
This is how the ac heaters is routed:
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The grounding is completely redone since that picture. The glue is just to keep the cables in place...
Fran: I think I will try your ground-breaking circuit!
And, yes the chassis is not grounded, and I know it can be dangerous if the AC gets in touch with the metal chassis.
But after the transformer I am separated from earth, and it's less dangerous.
The fact is, I don't have grounded AC wall outlets in my listening room
There are grounded outlets in the kitchen though.
We have 230V 50Hz here in Sweden by the way...
I will deal with this later. Until then I will be careful... I have a friend working as an electrician. Soon his learning-time will be out and he will get his certificate. Mabye he and I will install real grounded outlets later
I will look into the Aikido as soon as I get time!
ps. Thank you for your support guys! It's great fun building stuff when you get support
Get your friend to put a big earth spike in the ground just outside your listening room and earth the sockets in that room to it. In the meantime earth your aikido properly so that you're ready for it when you get the earthing sorted out.
We too are 230V 50Hz - but that situation would not pass any regulations here..... just be careful is all.....
Best of luck and yes it will sound much better when the hum is gone, partly because it will be quieter and partly because you fixed it!
Fran
We too are 230V 50Hz - but that situation would not pass any regulations here..... just be careful is all.....
Best of luck and yes it will sound much better when the hum is gone, partly because it will be quieter and partly because you fixed it!
Fran
ollebolle said:
And, yes the chassis is not grounded, and I know it can be dangerous if the AC gets in touch with the metal chassis.
Not only the A/C but how about the B+???
aveBut after the transformer I am separated from earth, and it's less dangerous.
We have 230V 50Hz here in Sweden by the way...
That's enough to ruin your day.....
I will deal with this later. Until then I will be careful... I have a friend working as an electrician. Soon his learning-time will be out and he will get his certificate. Mabye he and I will install real grounded outlets later
Here in the USA we use an 2 1/2 meter copper rod with 6ga. solid for an earth ground, cold water pipe too.
I have the same turntable, Pioneer PL12D2 !!!!
Very nice build OLLE. but ground it, we want to see more of your work.
Ron
edited for spelling