Simply awesome! So far, I've done a bog standard build two Mullard Gold Pin ECC88s with only the addition of Kiwames on cathode bypass duty, but it is significantly superior to my hotted up Pre 3 and CF designs. I is currently running off a slightly modded PSU3, to give 200v ht.
It will probably improve with a bit more running in, never mind a sprinkling of boutique components.
David
My New Aikido Cathode Follower Preamp
#4
http://glass-ware.stores.yahoo.net/acf9pin.html if its the same as mine
its in the instructions i think (not built mine)
its in the instructions i think (not built mine)
#5
Hi All,
It is indeed the second half of a traditional Aikido-an Aikido with no gain.
Greg, I think you would like this a lot, it really is a big step up from the CF, even in modded form, and very economical.
The link Dave gives doesn't work for me. Anyone else having problems? The circuit is in fact identical to the second half of the Aikido all in one, which does work on the site, but I will try and post when I get a chance.
The only bit that differs is that there is no psu decoupling between channels, which I guess Broskie did in the name of component count /simplicity.
I would expect to rap similar gains as I did on a basic CF design by introducing psu decoupling between channels.
The other beauty is it fits very nicely inside the WAD/WD Pre case, and runs very nicely off PSU3, with only a change to the dropper resistor. A big advantage!
David
It is indeed the second half of a traditional Aikido-an Aikido with no gain.
Greg, I think you would like this a lot, it really is a big step up from the CF, even in modded form, and very economical.
The link Dave gives doesn't work for me. Anyone else having problems? The circuit is in fact identical to the second half of the Aikido all in one, which does work on the site, but I will try and post when I get a chance.
The only bit that differs is that there is no psu decoupling between channels, which I guess Broskie did in the name of component count /simplicity.
I would expect to rap similar gains as I did on a basic CF design by introducing psu decoupling between channels.
The other beauty is it fits very nicely inside the WAD/WD Pre case, and runs very nicely off PSU3, with only a change to the dropper resistor. A big advantage!
David
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simon
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#6
That's interesting to hear. I've built a few Aikidos and had excellent results with a Broskie Cathode Follower (different animal) but I've never tried just an ACF. I may just need a pre without any gain so might try it one day.
#9
Yes, I have no problem opening the link davebms attached.
I'm a little confused but much of that is based on my own ignorance. I have never previously looked at any John Broskie designs. GlassWare Audio Design seems to be his commercial outlet based in the USA and the Aikido seems to be his exclusive design. Is that correct?
On the link davebms attached, at the bottom of the page is a link to the instruction manual for the build but that does not open for me in either IE or Safari, so I can't access the schematic. I really want to explore this further so any help would be much appreciated. I believe Mark (islandpink) has done a lot with some of Broskie's amp designs.
Dave, please can you answer the following.
Have you simply accessed the circuit online and adapted the CF final section for your own use or have you purchased the PCB from GlassWare Audio and built on that or have you done something totally different? Please give us (me) a more detailed description of what you have done. Thanks.
Greg
I'm a little confused but much of that is based on my own ignorance. I have never previously looked at any John Broskie designs. GlassWare Audio Design seems to be his commercial outlet based in the USA and the Aikido seems to be his exclusive design. Is that correct?
On the link davebms attached, at the bottom of the page is a link to the instruction manual for the build but that does not open for me in either IE or Safari, so I can't access the schematic. I really want to explore this further so any help would be much appreciated. I believe Mark (islandpink) has done a lot with some of Broskie's amp designs.
Dave, please can you answer the following.
Have you simply accessed the circuit online and adapted the CF final section for your own use or have you purchased the PCB from GlassWare Audio and built on that or have you done something totally different? Please give us (me) a more detailed description of what you have done. Thanks.
Greg
Last edited by Greg on Thu Aug 22, 2013 9:29 pm, edited 1 time in total.
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Paul Barker
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#10
I couldn't find the instruction manual either Greg.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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pre65
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#11
Nor me.Paul Barker wrote:I couldn't find the instruction manual either Greg.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
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IslandPink
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#12
I wouldn't say I've done a lot with Broskie's amp designs, but I have built an Aikido as a DHT-driver, and I have built the power supply ( 'T-Rex' ) that he and Steve Bench designed back in 2004 . That was what you heard powering my 4P1L/300B XLS amp at Owston.
The 'Aikido' circuit is John's invention, hardly 'exclusive', as he openly described it and its many variations, in 2004. He merely sells PCB's that make it easy to build for people building pre-amps and driver stages.
I met Broskie in 2005 at ETF . He was very interesting to talk to - a very sharp and self-confident guy who's also very imaginative - there are many very original and thought-provoking designs on his blog if you take the time to dig into the archives.
Dave Dove built some of his phono designs as well as the Aikido as a driver for his 300B amp that won the prize at Eggborough a few years ago.
The 'Aikido' circuit is John's invention, hardly 'exclusive', as he openly described it and its many variations, in 2004. He merely sells PCB's that make it easy to build for people building pre-amps and driver stages.
I met Broskie in 2005 at ETF . He was very interesting to talk to - a very sharp and self-confident guy who's also very imaginative - there are many very original and thought-provoking designs on his blog if you take the time to dig into the archives.
Dave Dove built some of his phono designs as well as the Aikido as a driver for his 300B amp that won the prize at Eggborough a few years ago.
"Once you find out ... the Circumstances ; then you can go out"
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IslandPink
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#13
It looks like what Dave has is the second half of the basic 'Aikido' circuit :
http://www.tubecad.com/2004/blog0011.htm
ie. it's the active-loaded cathode-follower, with the noise/distortion injection into the ( grid of the ) lower half of the CF , to improve PSRR and distortion.
http://www.tubecad.com/2004/blog0011.htm
ie. it's the active-loaded cathode-follower, with the noise/distortion injection into the ( grid of the ) lower half of the CF , to improve PSRR and distortion.
"Once you find out ... the Circumstances ; then you can go out"
#14
Things are becoming clearer. I sent an email to GlassWare Audio Design requesting the size of the AFC Buffer PCB. I got a reply from an address being tubecad.com which had John Bronskie's name attached as the replyer so I'm now pretty well convinced that David has used this kit or at least the relevant schematic. The PCB kit certainly will fit inside a WAD Pre 2/3 chassis being 4 X 6 inches as David has suggested.
In those circumstances, I'm inclined to shell out the $24 and give it a go.
Thank you David for bringing this to our attention. Just to be sure, it would be good if you could confirm I'm on the right track.
In those circumstances, I'm inclined to shell out the $24 and give it a go.
Thank you David for bringing this to our attention. Just to be sure, it would be good if you could confirm I'm on the right track.
#15
The website suggests several valve choice options. These are 6AQ8, 6CG7, 6DJ8/6922A, 6H30, 12AU7, 12AT7, 12BH7, 5963, 5965 and ECC99.
Please can you knowledgable valve aficionado's give me some guidance on which valves worth prioritising here?
Thank you.
Greg
Please can you knowledgable valve aficionado's give me some guidance on which valves worth prioritising here?
Thank you.
Greg