The ground could go to the chassis, wherever your "Star Ground" point is.
The biggest benefits are that you could keep the mess of wires to near nothing & you don't have to worry about your inputs needing to stay away from noisy stuff.
I believe that it also gives you 4 inputs instead of the three you asked for.
The biggest benefits are that you could keep the mess of wires to near nothing & you don't have to worry about your inputs needing to stay away from noisy stuff.
I believe that it also gives you 4 inputs instead of the three you asked for.
Thank you for the Bottlehead suggestion...I'll look into it. I think I'd really prefer the Akido preamp though. I'm beginning to understand conceptually how everything works. I think I'll be ok with tackling the Akido 12 Vac project though. According to a forum member I already have a preamp based on the Akido design. I bought it completely built. It has a slight hum and to be honest the PCB doesn't look as well made as John Broskie's. I'm really curious about the builders claims that say its better than a lot of the multi-thousand dollar brand name preamps out there. I'd like to see if this kit can produce a preamp that sounds as good or better than the one I already have. If not but it sounds decent, I'll delegate it to my secondary system. If it does sound as good I may still do that and perhaps attempt the 5687 All-In-One kit and hopefully use that with my main system.
As for the selector relay I like the wire management explanation.
As for the selector relay I like the wire management explanation.
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I started this thread during a time when I was laid off but still interested in building a kit and the Akido 12Vac kit seems like it is what I want not as a way of learning about electronics but also as a way of adding a nice piece of audio equipment to my system. I think I'm about to start a new job in a few weeks at the latest and if so will be able purchase this kit along with everything else needed to put everything together.
I still have questions and appreciate the feedback.
Yet one more question...
Is there a chance that after assembling this kit that there will be audible hum...either electrical or mechanical? Can someone tell me what are the main causes of electronic hum in electronics? I understand mechanical hum can come from either a poorly fastened transformer to he chassis or from the transformer itself. But I don't understand what can cause electronic hum that is audible through the speakers.
I'm going have review this whole thread but I'm pretty sure in addition to the Akido 12Vac I'm going to use a toroidal transformer as a power supply and a pre wired board for the switches and controls to simplified the construction.
Thank you again for the assistance.
I still have questions and appreciate the feedback.
Yet one more question...
Is there a chance that after assembling this kit that there will be audible hum...either electrical or mechanical? Can someone tell me what are the main causes of electronic hum in electronics? I understand mechanical hum can come from either a poorly fastened transformer to he chassis or from the transformer itself. But I don't understand what can cause electronic hum that is audible through the speakers.
I'm going have review this whole thread but I'm pretty sure in addition to the Akido 12Vac I'm going to use a toroidal transformer as a power supply and a pre wired board for the switches and controls to simplified the construction.
Thank you again for the assistance.
Hum can be caused by insufficient power supply filtering, poor physical layout, ground loops (internal and external), AC filament supply, among other things. Use a large case so you can keep the Aikido boards away from the power supply area. Internal shielding can help as well as a star ground.
John
John
Thank you. A larger chassis, in fact, is my choice, just to make assembly easier and less likely to become confused by wires becoming hard to trace. And as you say it may also make it easier to shield components. In my web surfing I found a chassis and ill have to go through my bookmarks to track it down again. If I remember it is extruded aluminum with heat sinks and reasonably priced...around $200. I'll probably used that face plate company to fabricate one to my design. I think I'll have a Bridgeport to use to drill or bore or machine any openings I'll need soon as well.....Thanks..
Keep you small signal wires as far away from AC sources as you can and shield them.
The under side of my aikido is pretty messy with my I/O wiring just hanging around free.
But, all of my I/O wiring is a few inches from the HV AC lines except for at the chassis RCA's where there is 1" space from them.
My Aikido is as quiet as the tubes I put in it.
There is NO hum at all and Broskie runs DC heaters and DC B+ so there is very little chance of noise from there.
So long as you take your "Star" ground directly to your chassis ground and take all other grounds to that star ground point then you should be very well off.
The under side of my aikido is pretty messy with my I/O wiring just hanging around free.
But, all of my I/O wiring is a few inches from the HV AC lines except for at the chassis RCA's where there is 1" space from them.
My Aikido is as quiet as the tubes I put in it.
There is NO hum at all and Broskie runs DC heaters and DC B+ so there is very little chance of noise from there.
So long as you take your "Star" ground directly to your chassis ground and take all other grounds to that star ground point then you should be very well off.
The aikido is dead quiet when wired properly.
Things that will help:
DC heaters
Shunt the ground with a small value resistor and film cap
Star ground...run a discrete wire for each hookup to the star
Shield your transformer...if supplied with a shield wire try different points within the build to tie it to. For whatever reason my last build I had to tie the xformer shield to the heater center tap on the PSU.
Things that will help:
DC heaters
Shunt the ground with a small value resistor and film cap
Star ground...run a discrete wire for each hookup to the star
Shield your transformer...if supplied with a shield wire try different points within the build to tie it to. For whatever reason my last build I had to tie the xformer shield to the heater center tap on the PSU.
OK...not to be driving this thread into the ground but I've run across the Transcendent Sound grounded grid preamp kit. Though everything is in this kit including a chassis and all the hardware I'm still gravitating towards actually going with most everyone's suggestions here about going with the Akido 12Vac kit along with using a toroidal transformer as a power supply and the selector PCB. I'd like to use a stepped attenuator for a volume control.
Can someone tell me if this preamp is at least equivalent in sound quality (as long as I don't mess up the build) to the grounded grid preamp or better?
I'm putting this project off because I've been laid off and was avoiding spending money on this project....but I do start a new job back up in my hometown of Chicago on August 12th. I have a good feeling about this company. The last place I worked was too stupid to see how stupid they are. I was hired to work in a position where I could have added a lot more value and the guy that was doing my job didn't know his *** from a hole in the ground. I'm pretty sure I was laid off because I was making about the same as the manager but since they made me a CNC programmer instead I couldn't clean up the managers mistakes as well as 'teach' someone with no CAD skills or machining skills to help save time on the project. Instead the kid crashed the spindle and caused $25,000 worth of damage and a week of down time....
Anyway... I still need to find a chassis to use as well. I'm considering a chassis that's fairly shallow in depth. I'd like to have the tubes exposed and if needed I'd find a cylindrical cover for the toroidal transformer so it can be mounted on top of the chassis as well.
All this time is giving me the ability to research this project plus read a book entitled 'Electronic Communication' that a technician/salesman at Parts Express gave me to keep. Looks like a good textbook for newbies like me.
Suggestions are appreciated...Thank you. Blake
Can someone tell me if this preamp is at least equivalent in sound quality (as long as I don't mess up the build) to the grounded grid preamp or better?
I'm putting this project off because I've been laid off and was avoiding spending money on this project....but I do start a new job back up in my hometown of Chicago on August 12th. I have a good feeling about this company. The last place I worked was too stupid to see how stupid they are. I was hired to work in a position where I could have added a lot more value and the guy that was doing my job didn't know his *** from a hole in the ground. I'm pretty sure I was laid off because I was making about the same as the manager but since they made me a CNC programmer instead I couldn't clean up the managers mistakes as well as 'teach' someone with no CAD skills or machining skills to help save time on the project. Instead the kid crashed the spindle and caused $25,000 worth of damage and a week of down time....
Anyway... I still need to find a chassis to use as well. I'm considering a chassis that's fairly shallow in depth. I'd like to have the tubes exposed and if needed I'd find a cylindrical cover for the toroidal transformer so it can be mounted on top of the chassis as well.
All this time is giving me the ability to research this project plus read a book entitled 'Electronic Communication' that a technician/salesman at Parts Express gave me to keep. Looks like a good textbook for newbies like me.
Suggestions are appreciated...Thank you. Blake
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I can say for myself that I LOVE my Aikido 9-pin All in One.
I like it more with bypassed cathode resistors on 6CG7's all around.
It drives my F4 very well and it's dead quiet.
I would highly recommend building a Broskie kit.
Your 12V toroid will fit inside of a large tuna can, smooth sides would be best instead of corrugated.
A little primer and paint and you have a toroid cover.
Then you could make tuna sammiches while you wait for the paint to dry.
The Antek AS-0512 would be MORE than enough, the AN-0212 would be fine with the secondaries in parallel but it doesn't have the static shield between the primaries.
I like it more with bypassed cathode resistors on 6CG7's all around.
It drives my F4 very well and it's dead quiet.
I would highly recommend building a Broskie kit.
Your 12V toroid will fit inside of a large tuna can, smooth sides would be best instead of corrugated.
A little primer and paint and you have a toroid cover.
Then you could make tuna sammiches while you wait for the paint to dry.
The Antek AS-0512 would be MORE than enough, the AN-0212 would be fine with the secondaries in parallel but it doesn't have the static shield between the primaries.
Attachments
Einric...That photo does make preamp look good. I take it the 9 pin all-in- one is what you have in the photo. I take it the 12Vac Akido is roughly the same size. Can you tell me the inside dimensions of that chassis are? Mine will probably have to be metal (aluminum or steel or both) just because all my woodworking tools will be packed away. I image if I put in long hours at work on my dime I can somehow bribe the Tool Room Supervisor to let me borrow a Bridgeport for a few hours.
I know we've been focusing on the 12Vac Akido just because the original Broski article talked about a Walwart PS...and simple components that are sold on the Glassware website..but a few contributors have talked about the 9 pin all-in- one. Considering how much I'm planning that's different than the Broski article how much more difficult is the 9pin over the 12Vac? Seems to me that perhaps I can go that route and have something better than the 12Vac....unless there is something about it that makes it more difficult to understand, assemble or troubleshoot in the build process....Blake
I know we've been focusing on the 12Vac Akido just because the original Broski article talked about a Walwart PS...and simple components that are sold on the Glassware website..but a few contributors have talked about the 9 pin all-in- one. Considering how much I'm planning that's different than the Broski article how much more difficult is the 9pin over the 12Vac? Seems to me that perhaps I can go that route and have something better than the 12Vac....unless there is something about it that makes it more difficult to understand, assemble or troubleshoot in the build process....Blake
you can also try the 6GU7 at the second stage..
for the first stage, you may want to try 6bq7, 6bk7, 7dj8...
i also tried the japanese 6R-RH2, if you want more gain, or the 6R-RH8...
the russian 6N23 is also very good at the first hole....
I have built 4 aikidos and I will say that the all in one is probably the easiest especially for your first one. 12v versus 250v is irrelevant, either way you need a power supply and or at least a transformer if you go all in one.
Your most flexible option is to go with a 9pin all in one kit. This offers the most variety with input and output tubes so you dont have to spend a bundle on exotics or har to find tubes.
Go with an all in one kit and a transformer from antek inc and done...add a couple rca jacks and a pot and voila you have a kick *** preamp.
Dont get bogged down on chassis. Ive seen people use cake pans from walmart. Also antek distributes par-metal products. Google search "ebay antek" and look at his chassis/enclosures. I have his 12x16x4 chassis and its really nice and was like $50. If you go that route just email john at antek with the xformer and chassis #s and tell him you are from diyaudio he will send you one complete PayPal invoice. Couldn't be easier.
Keep us posted
Ok....I know this thread seems to be taking forever for me to start...but I promise...I start my job this Monday and I'm going to start ordering parts, though it may take me a few more months to actually start building the preamp. I'm going to be staying with a few friends in Chicago while I'm looking for a place to live close to work. Anyway...I'm still reading and researching and since I don't know anything I need to ask questions that someone with a slight amount of knowledge may not need to ask.
I found this other thread today for an Akido preamp another member wants to sell. I'm convince I still want to build....but his post has me wondering about a few things again. First of all here is the other members post: http://www.diyaudio.com/forums/swap-meet/238081-fs-aikido-tube-preamplifier.html#post3590401.
In his post he has photos of the preamp with cover on and it shows a transformer which looks like its mounted to a PC board with a couple of caps on it. What is that PC board for and if I were to use a toroidal transformer for a power supply why is it that it seems I won't need it connected to a pc board? Or is that an option? Also in the first group of photos he shows the assembly without a choke? A few posts down he now shows it with a choke. What does a choke do? I've tried to research what it's for but maybe that's beyond my scope of understanding at this time. If the choke is optional what are the pros and cons of using one or not using one? If using one makes the preamp sound or perform better how do I go about spacing one out to use in the total assembly.
I've decided that I will building for a 12Vac power supply rather than 18Vac.
I'm figuring I'm going to start ordering the basic kit from Gassware in the next few weeks. Then the other components over the next weeks after that...and of course I'll probably have more questions after that.
Before I actually start ordering parts i will have a Bill of Material together so I hopefully minimize the number of incorrect parts I order.
Thanks...Blake
I found this other thread today for an Akido preamp another member wants to sell. I'm convince I still want to build....but his post has me wondering about a few things again. First of all here is the other members post: http://www.diyaudio.com/forums/swap-meet/238081-fs-aikido-tube-preamplifier.html#post3590401.
In his post he has photos of the preamp with cover on and it shows a transformer which looks like its mounted to a PC board with a couple of caps on it. What is that PC board for and if I were to use a toroidal transformer for a power supply why is it that it seems I won't need it connected to a pc board? Or is that an option? Also in the first group of photos he shows the assembly without a choke? A few posts down he now shows it with a choke. What does a choke do? I've tried to research what it's for but maybe that's beyond my scope of understanding at this time. If the choke is optional what are the pros and cons of using one or not using one? If using one makes the preamp sound or perform better how do I go about spacing one out to use in the total assembly.
I've decided that I will building for a 12Vac power supply rather than 18Vac.
I'm figuring I'm going to start ordering the basic kit from Gassware in the next few weeks. Then the other components over the next weeks after that...and of course I'll probably have more questions after that.
Before I actually start ordering parts i will have a Bill of Material together so I hopefully minimize the number of incorrect parts I order.
Thanks...Blake
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