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 Post subject: Aikido DIY preamp
PostPosted: Sun Jun 18, 2017 11:15 am 
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Joined: Tue Apr 24, 2012 11:35 am
Posts: 386
Location: Stoney Creek, ON, CA
I have read some very good reviews on these preamps
Are they only available in a kit or can you buy them assembled??
If anyone has one or has a opinion on this preamp I would appreciate any input
I would be paring it up with a YBA 2A amp

Thanks


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 Post subject: Re: Aikido DIY preamp
PostPosted: Mon Jun 19, 2017 4:02 am 
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Joined: Thu Jul 25, 2013 2:39 am
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Location: Copenhagen, , DK
Seems it's possible to send an email to sales@tubecad.com (http://glass-ware.stores.yahoo.net/index.html ---> http://glass-ware.stores.yahoo.net/info.html) and ask them if they can assemble an Aikido DIY preamp for you, and if it's possible I don't think it will cost much extra. Also keep in mind that tubes have limited life span maybe 5 - 6 years before tube replacement, so you need to ask the company if it's possible to send the preamp to the company and let them replace the tubes for you in the future when that time comes.

https://www.canuckaudiomart.com/forum/viewtopic.php?f=9&t=36703&start=15
http://www.diyaudio.com/forums/tubes-valves/175683-my-first-diy-experience-aikido-tetra-preamp.html

'Erik' from https://www.canuckaudiomart.com/forum/viewtopic.php?f=9&t=36703&start=30 mentioned that it's possible to get an login id on diyaudio, and post a wanted ad in the "swap meet" forum (http://www.diyaudio.com/forums/swap-meet/). There are many folks that love building gear there, and they sell what they've built to fund the next project. I've no idea if they do build and sell Aikido DIY preamp there, but it's worth try to check it out.

http://www.instructables.com/id/How-to-solder/
http://www.instructables.com/id/How-to-solder-the-secrets-of-good-soldering/
http://www.wikihow.com/Solder-Electronics
https://www.build-electronic-circuits.com/how-to-solder/
http://www.aaroncake.net/electronics/solder.htm

https://www.youtube.com/watch?v=H3-TfdZVBCc
https://www.youtube.com/watch?v=AqvHogekDI4
https://www.youtube.com/watch?v=GDcp5l4kqR8

http://www.nmr.mgh.harvard.edu/~reese/electrolytics/
Quote:
WARNING - this method obviously leaves wires exposed while you work. These wires are potentially at HIGH VOLTAGES which can kill. For example, if you rest your right hand on the variac (ground) and touch the exposed clip leads, that will form a circuit from one arm, through your chest, and down through the other arm - potentially causing cardiac arrest. To me, this seems no more hazardous than working around live tube equipment with the covers off, though extreme caution is warranted in both cases. Proceed at your own risk!

http://diyaudioprojects.com/Tubes/tubes.htm
Quote:
Do-It-Yourself (DIY) vacuum tube (valve) amplifier and tube preamplifier projects. Please be aware that most of these vacuum tube projects use potentially lethal voltages that can kill you so do not attempt them if you are not familiar with high voltage safety! Some of the projects use low voltage and if you are new to tubes and high voltage safety you should start with these. For books on the subject of vacuum tubes, see our DIY Audio Book recommendations.


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 Post subject: Re: Aikido DIY preamp
PostPosted: Mon Jun 19, 2017 11:34 am 
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Joined: Tue Apr 24, 2012 11:35 am
Posts: 386
Location: Stoney Creek, ON, CA
Elos,

Thanks for the information, I will follow up on this :)


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 Post subject: Re: Aikido DIY preamp
PostPosted: Mon Jun 19, 2017 3:17 pm 
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Joined: Sun Oct 05, 2008 7:23 pm
Posts: 1040
Location: Victoria, BC, CA
http://www.diyaudio.com/forums/swap-mee ... -6sn7.html


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 Post subject: Re: Aikido DIY preamp
PostPosted: Mon Jun 19, 2017 3:45 pm 
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Joined: Fri Jun 28, 2013 5:25 pm
Posts: 30
Location: St-Leonard, QC, CA
Aikido > Tubes4hifi.com> Don Sach

It seems http://www.tubes4hifi.com/pre11.htm preamps are based on a Aikido design.

http://www.dsachsconsulting.com/custom%20line%20stage.html preamp is a custom tube4hifi SP14 with premium parts.


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 Post subject: Re: Aikido DIY preamp
PostPosted: Mon Jun 19, 2017 4:17 pm 
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Joined: Wed Sep 14, 2005 11:47 am
Posts: 3807
Location: Ottawa, ON, CA
markmiata wrote:
I have read some very good reviews on these preamps
Are they only available in a kit or can you buy them assembled??
If anyone has one or has a opinion on this preamp I would appreciate any input
I would be paring it up with a YBA 2A amp

Thanks

Image

Well a few comments

- this circuit has high voltages, so if your not used to working with electric circuits
this is not the place to begin
- the volume pot, output cap and tube will dominate the sonics.
- if you go with DIY make sure you calculate a bill of materials before you begin
the cost of the case, volume pot, output cap, power supply can add up pretty quickly.

- the Akido circuit can be reconfigured depending on the type of tube desired

- I see someone designed these circuit boards placing a tube re beside an electrolytic cap - oops.

- the good thing about the Akido design is that there is only 1 cap in the signal path.
in this case its value is only 0.47 uF.
Meaning that you can buy a higher end cap at a lower cost if its only 0.47 uF

- does your YBA 2A amp have jFET's or bipolar transistors in the first stage ?


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 Post subject: Re: Aikido DIY preamp
PostPosted: Mon Jun 19, 2017 4:30 pm 
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Joined: Sun Nov 01, 2009 7:20 pm
Posts: 179
Location: Medicine Hat's where E's at, AB, CA
I am currently in the final stages of building my 2nd point-to-point Aikido-based (buffer stage, with 2 tubes) preamp. My first one uses the E88CC/6922/6DJ8 tubes, the latest will use the 12AX7 and its many variants.

Not a gain stage, the "Aikido Cathode Follower" has less than unity gain (around 0.94 - 0.98 depending on tube version selected), which in some cases is desired, and offers a means to improve the synergy between a high-impedance source and low-ish impedance amplifier.

It is not uncommon to read on other forums about Aikido preamp users (the gain stage version, with 4 tubes) trying to tame down the excessive gain that their units provide. Broskie (the tube Guru behind all the "Aikido" topology) also offers a high-quality attenuator module (the A3) that can be used to put things under fine control if the source signals are a bit too strong.

The reason I started experimenting with this type of buffer/preamp is because I had purchased a Decware CSP2+ headphone amp/preamp to be used as a tube preamp, but my experience with it is far from satisfactory. Like most gain stages, it offered way too much useless signal gain, was waaaaaay too noisy on every setup that I could throw it at, unreliable, picky with tubes, and simply proved to be ill-suited to work as I intended it to. To this day I have cured all of its vices and shortcomings, and learned a whole lot about tube-based gear, but even still I don't think that gain stages are for everyone.

I had also built an experimental gain stage unit based on Decware's "Z-Kit" cheesy schematic. Same deal: too noisy out of the box, way too much gain, and a completely unjustified use of passive components. I have already taken it all apart to re-use some bits on future builds.

Enter the Aikido buffer stage, and as my first build is already out being test-driven by another local CAMmer with positive feedback, my second unit can not be ready soon enough.

My experience with the first unit is that it's incredibly quiet, which is a nice thing to achieve when using tube rectification. I tried it with both SS and tube amplifiers and I am not going back to anything else.


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 Post subject: Re: Aikido DIY preamp
PostPosted: Mon Jun 19, 2017 6:24 pm 
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Joined: Sun Dec 28, 2008 7:49 am
Posts: 1625
Location: Fairport Beach (in Pickering), ON, CA
Glad to hear you like it. I've had the pre/PS boards here for a few years and haven't gotten around to building it yet. :D

_________________
Tom

Collecting vintage tube Pilot (Pilotone) HiFi gear.


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 Post subject: Re: Aikido DIY preamp
PostPosted: Tue Jun 20, 2017 6:47 am 
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Joined: Tue Jun 02, 2009 10:04 am
Posts: 60
Location: ottawa, ON, CA
Glassware audio has 2 low voltage aikido pre amp kits that are quite reasonably priced. The 12 volt can run from a simple wall wart or switching power supply.
The shipping is very reasonable from this company as well. I think for around $120 shipped you can have a nice little Aikido Preamplifier. I intend to have a go at one of these soon as well.


http://glass-ware.stores.yahoo.net/aikido12vac.html

http://glass-ware.stores.yahoo.net/aikidolv.html


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 Post subject: Re: Aikido DIY preamp
PostPosted: Tue Jun 20, 2017 8:06 am 
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Joined: Sat Feb 12, 2011 8:14 am
Posts: 77
Location: Windsor, ON, CA
Before, making any specific Aikido recommendations...
One would first need to know how much 'Gain' the OP requires.
--
As mechstek has already touched upon above...
I believe, that both of the 'above cited' LV Line-Stage Amplifiers have a fair amount
of (excessive?) Signal Gain... For Digital Sources (Amplification Factor: 14 to 22).

Therefore, one of John Broskie's Tube-Based Buffers... 'May or May Not' be more appropriate gain wise.

http://glass-ware.stores.yahoo.net/tubu.html

Then again, maybe the OP is planning on using this Preamp with an Analog Front End and a separate Phono Preamplifier? Thank-you! -Tim.
_______


Last edited by Takira71A on Tue Jun 20, 2017 11:37 am, edited 2 times in total.

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 Post subject: Re: Aikido DIY preamp
PostPosted: Tue Jun 20, 2017 11:35 am 
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Joined: Tue Apr 24, 2012 11:35 am
Posts: 386
Location: Stoney Creek, ON, CA
Hi Guy's

To be perfectly honest I'm totally new to the tube pre amp field :(
The question was asked??? does your YBA 2A amp have jFET's or bipolar transistors in the first stage ???
And I'm sorry to say I don't really know

The other question was asked,

Before, making any 'specific' Aikido recommendations...
One first would need to know how much 'Gain' the OP requires.
--
As mechstek has already touched upon above...
I believe, that both of the 'above cited' LV Line-Stage Amplifiers have a fair amount
of (excessive?) Signal Gain... For Digital Sources (Amplification Factor: 14 to 22).

Therefore, one of John Broskie's Tube-Based Buffers...
'May or May Not' be more appropriate Gain wise.

I have no idea how much gain I would need or how I would even figure out that information

Once again as I read this I'm totally lost and really feel like I'm over my head here...I honestly thought I could just buy a assembled kit and it would work fine, But I'm beginning to think that really isn't the case??

I have been offered a professionally built kit by another CAM member for $ 600 with the remote,
But now I'm wondering if I really don't know what I'm getting into and might not be happy with the results without not really knowing that much about my amp or the product I'm considering buying

I really don't know what my next move should be
Any advice would be greatly appreciated

Thanks


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 Post subject: Re: Aikido DIY preamp
PostPosted: Tue Jun 20, 2017 2:09 pm 
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Joined: Mon Dec 06, 2004 4:55 pm
Posts: 451
Location: Calgary, AB, CA
If you want to try DIY take a look at "bottlehead" kits, the basic starter preamp is about $100.00 US and may or may not work with your amp so consider it a soldering lesson without lethal voltages.
Good luck on whatever you choose.


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 Post subject: Re: Aikido DIY preamp
PostPosted: Tue Jun 20, 2017 2:42 pm 
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Joined: Wed Sep 14, 2005 11:47 am
Posts: 3807
Location: Ottawa, ON, CA
mechstek wrote:
Like most gain stages, it offered way too much useless signal gain,


Bingo -this is what I've found too - I built an SSPR - with a voltage gain ~ 3.8
and that's way too much.
Then took a cathode follower and added a current source.
The maximum gain with a shunt volume control is 0.8 (which actually attenuates the signal)
and that is plenty of signal for a power amp.

When building audio equipment - using a star audio grounding technique is quite important.
With a cathode follower, the output cap, volume control and tube will dominate the sonics.

-- 20 Jun 2017 22:45 --

markmiata wrote:
The question was asked??? does your YBA 2A amp have jFET's or bipolar transistors in the first stage ???

This is important to find out.
Most tube preamps will have the poop (current) to drive the stray capacitance of a jFET.
Where as a tube preamp may or may not be able to effectively drive a bi polar transistor.

BTW - the YBA 2A is a beautifully made amplifier - the power transformers are poetry.


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 Post subject: Re: Aikido DIY preamp
PostPosted: Thu Jun 22, 2017 4:23 am 
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Joined: Wed Sep 14, 2005 11:47 am
Posts: 3807
Location: Ottawa, ON, CA
mechstek wrote:
I am currently in the final stages of building my 2nd point-to-point Aikido-based (buffer stage, with 2 tubes) preamp. My first one uses the E88CC/6922/6DJ8 tubes, the latest will use the 12AX7 and its many variants.

Not a gain stage, the "Aikido Cathode Follower" has less than unity gain (around 0.94 - 0.98 depending on tube version selected), which in some cases is desired, and offers a means to improve the synergy between a high-impedance source and low-ish impedance amplifier.


A few things I've learned
- not sure why the Akido boards put caps right beside a tube - the heat from the tube will slowly degrade the cap
- check to see if the heaters need "lifting"
- using a star ground node is quite important (so everything gets referenced to the same "0" volts).
- even though film caps are non polarized the outside of the foil should go to the low impedance side of the circuit
- the 2 triode version of the Akido Cathode follower is nothing short of brilliant
because the bottom triode functions as a current source that adjusts with power supply noise.
So the PSRR must be quite good.
- the Clarity Cap CSR may be a best value cap - some other caps like WIMA's sound a bit rough.
.


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 Post subject: Re: Aikido DIY preamp
PostPosted: Thu Jun 22, 2017 9:34 pm 
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Location: Medicine Hat's where E's at, AB, CA
Uunderhill wrote:
A few things I've learned
- not sure why the Akido boards put caps right beside a tube - the heat from the tube will slowly degrade the cap
- check to see if the heaters need "lifting"
...


I am not sold on the idea of using PCB's with tube gear, but if I was building one of those buffer or gain stages on a bare PCB I would mount all the passive components on the underside of the board and get the sockets to sit flush with the top of the chassis to help get the heat to the outside.

From what I can gather, the Glass-Ware boards do not have the heater-to-B+ reference built in, although the instructions do point you in that direction and the circuit will need to be included as with every other design that calls for stacked Triode elements with such high B+. Unless you are Steve Deckert at Decware, who doesn't think that such safety net is necessary. Or maybe he still doesn't know? :o


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