The old telefunken transformer was broken. Too bad 
The primary winding was off somewere...
Luckily I had an old transformer taken from an old Tandberg taperecorder!
Tonight's work:
The transformer and choke is now mounted! I have a plate to shield the amplifier from the powersupply...
The primary winding was off somewere...
Luckily I had an old transformer taken from an old Tandberg taperecorder!
Tonight's work:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
The transformer and choke is now mounted! I have a plate to shield the amplifier from the powersupply...
Hi Ollebolle,
Got to wait a month for them as my other half is bringing them back from USA after her trip to Miami in 2 weeks.
We have a friend who lives in the Keys luckily.
Regarding the muting switch have you any advice what I need to buy here and how to install it in the output path?
Thanks
Got to wait a month for them as my other half is bringing them back from USA after her trip to Miami in 2 weeks.
We have a friend who lives in the Keys luckily.
Regarding the muting switch have you any advice what I need to buy here and how to install it in the output path?
Thanks
Yes, I did also think it was good old german quality.
I didn't buy mine at ebay, i found it in a broken radio at the local junkyard
Some say the speakers are good so I saved them.
I didn't buy mine at ebay, i found it in a broken radio at the local junkyard
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Some say the speakers are good so I saved them.
The heaters are working!
Tomorrow I will start soldering the components
An externally hosted image should be here but it was not working when we last tested it.
Tomorrow I will start soldering the components
I have made a 2,5mm2 wire for the grounding, and I have also mounted some components...
Now I have a question
The power supply is going to be a simple LC filter. I might add a small R and some C after that...
I have installed two switches. One powers up the heaters, then I wait a few seconds and hit the other switch for my B+.
I want to be kind to the tubes
Where would you place the B+ switch? Before or after the power supply?
Transformer --> switch --> powersupply with choke --> amplifier
or: Transformer --> powersupply with choke --> switch --> amplifier
An externally hosted image should be here but it was not working when we last tested it.
Now I have a question
The power supply is going to be a simple LC filter. I might add a small R and some C after that...
I have installed two switches. One powers up the heaters, then I wait a few seconds and hit the other switch for my B+.
I want to be kind to the tubes
Where would you place the B+ switch? Before or after the power supply?
Transformer --> switch --> powersupply with choke --> amplifier
or: Transformer --> powersupply with choke --> switch --> amplifier
For maximum quietness, I might suggest keeping the circuit ground and earth ground separate. Just connect the circuit ground to earth/chassis with a capacitor, something along the lines of 0.01uF, ceramics are good for this. This will also avoid any potential ground loops.
Nice work so far. I did the octal aikido thing with broskie's boards, and the sound turned out quite nice.
Nice work so far. I did the octal aikido thing with broskie's boards, and the sound turned out quite nice.
woodturner-fran: It would be nice to have two separate transformers
Boris_The_Blade: As you see I have my ground-wire directly connected to the chassi.
You suggest to connect the signal-ground to chassi through a ceramic cap?
I got another tip: make a ground-lift!
I don't know what's best. It's allways so many different ways to do it!
Boris_The_Blade: As you see I have my ground-wire directly connected to the chassi.
You suggest to connect the signal-ground to chassi through a ceramic cap?
I got another tip: make a ground-lift!
I don't know what's best. It's allways so many different ways to do it!
Now I have changed the grounding completely Now I use bus-bars!
The blue wires are B+ One per channel.
There is also power supply ground, signal ground for right channel, signal ground for left channel, and they are all connected to the same point, and then chassis connection.
I think this is much better!
Now I use bus-bars!An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
The blue wires are B+ One per channel.
There is also power supply ground, signal ground for right channel, signal ground for left channel, and they are all connected to the same point, and then chassis connection.
I think this is much better!
Hi Olle,
I've been following this thread plus previous others on this forum. I am building an Aikido myself right now. But I'm using octals (12SL7 and 12SN7). Your construction work is very nice, tidy!! Mine is point-2-point soldering like yours but it's far from your excellent build. I've taken note of some of your wiring methods, which I hope to use/follow in later projects.
I'm using a single bus-bar to which all signal grounds are connected. I don't know how it will sound. Still have another week to complete with power supply (300V recommended). Hope to report on listening experience when finished.
Good luck with your work, Ollebolle!!
Joe A
I've been following this thread plus previous others on this forum. I am building an Aikido myself right now. But I'm using octals (12SL7 and 12SN7). Your construction work is very nice, tidy!! Mine is point-2-point soldering like yours but it's far from your excellent build. I've taken note of some of your wiring methods, which I hope to use/follow in later projects.
I'm using a single bus-bar to which all signal grounds are connected. I don't know how it will sound. Still have another week to complete with power supply (300V recommended). Hope to report on listening experience when finished.
Good luck with your work, Ollebolle!!
Joe A
Thank you Joe!
I built my EL84 SE amplifier with one ground bus, and it worked out good!
The disadvantage with one ground bus is that you might get more hum. But if your amp turn out to be quiet enough, why change something that is working?
Good luck with your amp! I hope to see it in the tube amp gallery later
I built my EL84 SE amplifier with one ground bus, and it worked out good!
The disadvantage with one ground bus is that you might get more hum. But if your amp turn out to be quiet enough, why change something that is working?
Good luck with your amp! I hope to see it in the tube amp gallery later
I consider myself a newbie in this hobby/craft. My reasoning was that even if I used separate left & right grounds they still need to be joined together to chassis.
What I did is I paid attention to solder all the signal grounds of one channel to one side of the busbar (say the left side) and the signal grounds of the other channel on the other side of the bar.
I will then take the signal grounds to chassis from somewhere in the middle of the busbar, between the two channels.
I don't know if I'm missing something. Maybe other members can enlighten the newbie community about the secrets of grounding.
Regards to all.
JA
What I did is I paid attention to solder all the signal grounds of one channel to one side of the busbar (say the left side) and the signal grounds of the other channel on the other side of the bar.
I will then take the signal grounds to chassis from somewhere in the middle of the busbar, between the two channels.
I don't know if I'm missing something. Maybe other members can enlighten the newbie community about the secrets of grounding.
Regards to all.
JA
I do it this way. Connect together grounds from aikido stages together to one point, then connect this point to groundl lug of filter capacitors, which are feeding the channel, then from capacitors connect it to chassis, but not to the safety earth point (one from power plug).
Do the same for second channel. Both channel will have just same connectio nto the chassis at one spot.
Hope you understand.
Do the same for second channel. Both channel will have just same connectio nto the chassis at one spot.
Hope you understand.
Thanks kacernator,
Just to check whether I understood you correctly :
- each Aikido channel has 2 stages, so each stage gets its own ground point.
- All four stages (input & output stage for each stereo channel) are then brought to one point (star ground point?).
- Since I'm using one PS to drive both channels, this common ground point is connected to -ve lug/s of the PS caps.
- This PS -ve is then connected to chassis.
- Safety earth point then goes to chassis.
I am aware that others may have a different grounding scheme. This is what makes grounding a frustrating (sometimes confusing) subject.
Anyway, Thanks for your patience.
Regards.
Joe A
Just to check whether I understood you correctly :
- each Aikido channel has 2 stages, so each stage gets its own ground point.
- All four stages (input & output stage for each stereo channel) are then brought to one point (star ground point?).
- Since I'm using one PS to drive both channels, this common ground point is connected to -ve lug/s of the PS caps.
- This PS -ve is then connected to chassis.
- Safety earth point then goes to chassis.
I am aware that others may have a different grounding scheme. This is what makes grounding a frustrating (sometimes confusing) subject.
Anyway, Thanks for your patience.
Regards.
Joe A
Now I have stayed up late soldering again
An externally hosted image should be here but it was not working when we last tested it.
;
Very nice Ollebolle. Can't wait to get started on mine. Parts will be arriving next weekend.
I'm very busy at the moment trying to fix a DC offset on my SS power amp. Very problematic. Testing and changing many parts.
I'm getting 40mV on the left channel.
I expect to be back with questions about my future Aikido very soon.
Good luck
I'm very busy at the moment trying to fix a DC offset on my SS power amp. Very problematic. Testing and changing many parts.
I'm getting 40mV on the left channel.
I expect to be back with questions about my future Aikido very soon.
Good luck
Well, the power supply is almost done
I used a power supply made by Broskie. I found it in the Aikido pdf.
I haven't mounted the diode over the choke yet, because I don't know what it does??
The load is a bunch of power resistors at 4700ohms. That is very close to the tube resistance.
I got 217V B+ That's very close to 220V at the schematic
I was not using any cap before the choke to ground. If i put a small cap there I think I will get a few more volts, but I think it is good as it is! There are variations on the main power anyway...
The capacitor is Philips 470µF. I know that this size is not needed, but I found 14 of these in some kind of industrial machine some weeks ago, so it was free
I used a power supply made by Broskie. I found it in the Aikido pdf.
An externally hosted image should be here but it was not working when we last tested it.
I haven't mounted the diode over the choke yet, because I don't know what it does??
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
The load is a bunch of power resistors at 4700ohms. That is very close to the tube resistance.
I got 217V B+ That's very close to 220V at the schematic
I was not using any cap before the choke to ground. If i put a small cap there I think I will get a few more volts, but I think it is good as it is! There are variations on the main power anyway...
The capacitor is Philips 470µF. I know that this size is not needed, but I found 14 of these in some kind of industrial machine some weeks ago, so it was free