Hi!
I have built some tube amplifiers, so now I want to build a preamplifier!
Preamplifier and linestage is the same thing, right?
This is what I am looking for:
*Low Distortion
*Low output impedance
Then I read about the Aikido
http://www.tubecad.com/2004/blog0011.htm
http://www.tubecad.com/2005/January/blog0030.htm
So I started with the enclosure:
It's a modified printerswitch in aluminium
The tubes are 6N1P:s and 5687:s!
But a friend told me, he had bought pcb:s and in the documentation there was another shematic, not the one I found. He is using the same tubes...
His schematic was called "Revision A Line Amplifier" It was a bit different, so I wonder:
Which schematic shall I use?
I want to use the best one!
ps. I don't want to use pcb:s. That's uncool
I have built some tube amplifiers, so now I want to build a preamplifier!
Preamplifier and linestage is the same thing, right?
This is what I am looking for:
*Low Distortion
*Low output impedance
Then I read about the Aikido
http://www.tubecad.com/2004/blog0011.htm
http://www.tubecad.com/2005/January/blog0030.htm
So I started with the enclosure:
It's a modified printerswitch in aluminium
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.
An externally hosted image should be here but it was not working when we last tested it.
The tubes are 6N1P:s and 5687:s!
But a friend told me, he had bought pcb:s and in the documentation there was another shematic, not the one I found. He is using the same tubes...
His schematic was called "Revision A Line Amplifier" It was a bit different, so I wonder:
Which schematic shall I use?
I want to use the best one!
ps. I don't want to use pcb:s. That's uncool
The nice thing about point to point is the ease of moving things around and changing values. So, in a sense, you can find out for yourself. The one modification I'd make is to put a trimpot in the nulling resistor string to adjust out the noise more perfectly- the ratio of the resistors is very sensitive to tube gain.
I´ve got the Aikido 9-pin mono boards. They arrived together with the rev. B circuit description (last year). Last time I looked at the Tubecad.com the rev. A description + circuit was still shown. I can´t say exactly which changes were made between rev. A and B.
However, both rev. A and rev. B unfortunately have (small) typos. I have mailed John Broskie about these bot I haven´t heard from him and I think that they have still not been corrected.
If you want a copy of the rev. B then please drop me an email with your private email address and I will send it to you. WARNING! The file is huge (several MB´s - if I remember correctly) beacuse I haven´t found out to use my scanner correctly
I have decided to do the same as SY is suggesting - using a good quality trimpot for optimizing the circuit. I got the inspiration from another thread from this site.
Kind regards
Karsten
However, both rev. A and rev. B unfortunately have (small) typos. I have mailed John Broskie about these bot I haven´t heard from him and I think that they have still not been corrected.
If you want a copy of the rev. B then please drop me an email with your private email address and I will send it to you. WARNING! The file is huge (several MB´s - if I remember correctly) beacuse I haven´t found out to use my scanner correctly
I have decided to do the same as SY is suggesting - using a good quality trimpot for optimizing the circuit. I got the inspiration from another thread from this site.
Kind regards
Karsten
Hi Olle,
I am in the process of ordering an Aikido too. I'm a total newbie so I'm choosing the Octal PCB. It's going to be
I was going to use a SS SKP Mosfet power amp (100+100W) but now I'm thinking of having a go at a tube power amp at the same time.
What do you think of partnering a dnyakit ST-35 or ST-70 with the Aikido line stage amp?
Cheers,
Chris
I am in the process of ordering an Aikido too. I'm a total newbie so I'm choosing the Octal PCB. It's going to be
I was going to use a SS SKP Mosfet power amp (100+100W) but now I'm thinking of having a go at a tube power amp at the same time.
What do you think of partnering a dnyakit ST-35 or ST-70 with the Aikido line stage amp?
Cheers,
Chris
I don't know much about dynakit amps, but I think it will work just fine! The aikido with it's low distortion and low output impedance should suit most "normal" power amplifiers.Brit01 said:
Besides:Tube amps are often easy to drive!
And: Choose tubes wisely! I would listen to Broskie's reccomendations!
beetel said:
I don't think they are that close
25mm And I don't think the distance between the tubes changes the sound...
Haven't really thought about that
Mabye if they are mounted to close to each other, it would result in warmer tubes, I guess...
Now I have found an old power transformer! I took it from a broken Telefunken radio at the junk yard
Both 6,3V and 262V. Nice
Now I can move forward with the project! I have most if the parts needed!
An externally hosted image should be here but it was not working when we last tested it.
Both 6,3V and 262V. Nice
Now I can move forward with the project!
I have most if the parts needed!
I am thinking about using a choke in the power supply!
I have an old choke, but I think it can not handle more current than ~70-80mA.
I'm using 6N1P and 5687-tubes and this schematic
Do anyone know how big the current will be in the power supply?
I want to know if I can use my choke
I have an old choke, but I think it can not handle more current than ~70-80mA.
I'm using 6N1P and 5687-tubes and this schematic
Do anyone know how big the current will be in the power supply?
I want to know if I can use my choke
Hi Ollebolle,
get the Mono....revA.pdf that includes a table with lots of tubes listed and according component values, current draw and such.
When you can't find it I can mail it to you (when Karsten didn't already mail you the revB which also includes the table).
Your current draw should be in the vicinity of 45 - 50mA (didn't look it up) but well below 70mA.
regards,
Oliver
get the Mono....revA.pdf that includes a table with lots of tubes listed and according component values, current draw and such.
When you can't find it I can mail it to you (when Karsten didn't already mail you the revB which also includes the table).
Your current draw should be in the vicinity of 45 - 50mA (didn't look it up) but well below 70mA.
regards,
Oliver
Hi guys,
I'm just about to order the Aikido Stereo 9-pin kit from JB.
I'm a total newbie.
I was donated 4 6N1P valves from a very kind member from Netherlands.
I will probably have to have a transformer built by a local tech here. I live in Uruguay so very little available. My girlfriend will be in USA in Oct so I am getting her to bring the kit and parts back from JB.
Exactly what kind of transformer do I need to have built. I understand I need the 6.3 V DC supply for the 6N1P. We have 230 V here.
Also do I need to order the following from the kit?
'Supporting and power supply caps'.
I'm also getting hold of the power supply board from another member.
Many thanks
Chris
I'm just about to order the Aikido Stereo 9-pin kit from JB.
I'm a total newbie.
I was donated 4 6N1P valves from a very kind member from Netherlands.
I will probably have to have a transformer built by a local tech here. I live in Uruguay so very little available. My girlfriend will be in USA in Oct so I am getting her to bring the kit and parts back from JB.
Exactly what kind of transformer do I need to have built. I understand I need the 6.3 V DC supply for the 6N1P. We have 230 V here.
Also do I need to order the following from the kit?
'Supporting and power supply caps'.
I'm also getting hold of the power supply board from another member.
Many thanks
Chris
Watch those telefunken transformers - I bought 4 of those online and all of them were bad. The various voltages are derived by taps off a single winding. Caused me no end of grief at the time until I found out what was wrong. Also watch out for the 6.3V winding being heavy enough to support the 4 tubes.
The rev A and rev B just refer to different versions of his board where there are jumpers you can add to use different tube types. The basic circuit is still the same and if you download the booklet all the critical values are in there for all of the tube types.
Great preamp....
Fran
The rev A and rev B just refer to different versions of his board where there are jumpers you can add to use different tube types. The basic circuit is still the same and if you download the booklet all the critical values are in there for all of the tube types.
Great preamp....
Fran
No, in total for both channels. I just looked through the revB.pdf shortly, so with a B+ of 300V your current draw should be 40mA (5+5mA for the 6N1P and 15+15mA for the 5687). When the choke itself is fine you should be okay...
Don't be too sure on this...transformers, especially old ones can devellop all kinds of nastities
(does this word exist
) like mechanical hum, running hot and so on... But rig it up on a breadboard and try it out.
Good luck!