• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Aikido Octal line stage kit info needed

BillWojo

Member
2014-10-30 3:54 am
NJ
I'm about to purchase an unbuilt Aikido Octal line stage kit, includes board and all parts to build the board along with a matched quad of RCA 12SN7 tubes. Comes with the manual for 100 bucks. I have heard good things about GlassWare kits and their performance.
What I want to do is to use this as a preamp to drive my Mac MC40 amps. I'm currently working on a Dynaco PAS3X, rebuilding with new boards and power supply but I'm thinking this might perform better.
I'm not familiar with building kits from scratch, this Aikido is going to need a PS and GlassWare is not getting back to me. Seems a common complaint.
So if I get this kit, what am I in for? Do the manuals give enough information for a tube novice to get by with?
By the way, this is not the stereo octal line stage shown on his website but an older version that has all 4 tubes in a single row. Rev B. Has anyone used this version?
So what advise can you guys give me?
Thanks

BillWojo
 
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I've ordered a lot of boards from Glassware and never had an issue, but I've never sent correspondence so I can't comment on him not getting back to you. I have a buddy who has the Akido octal set and he really likes it. The boards are top quality. The only "issue" if you want to call it that, is the built in flexibility of the boards. For example, there are a number of ways to configure the heater and ground connections. This can become confusing for people! The boards I've used from him (all PS boards) have been excellent quality. My advice to a complete novice is, however, buy the all in one board that includes the PS and go with the simplest possible heater configuration. Oh, and speaking of heaters, be sure to get an appropriate transformer. Can be easy to undersize the heater winding.
 
I have built The all in one nine pin as well as a point to point wired octal Aikido. They both sound great. The nine pin was one of my first builds and it took me a bit to work out grounding to make the system hum free. As smbrown stated the options can be confusing for a new builder.

I started this hobby with a pair of mc30 amps. They sounded very nice. I sold them when I learned how much they are worth.

I believe that your mc40 amps will produce full power output from a 2 volt input. Most sources produce 2 volts. What I'm getting at is you probably don't need a preamp. I drove my mc30s with a passive preamp. A direct coupled b1 buffer might be a better choice then the Aikido. simpler build and will get the job done.
Food for thought.
Evan
 
Just wondering if you ended up building this pre? I have built the version you are discussing. Glassware has power supply circuit boards for low voltage and high voltage both. I used there low voltage heater circuit and my own high voltage circuit. I have been using my pre for about 8 years now. If you still need info let me know.
 
Bill,
Ditto on the filament trans. Choose one with about 2X the AC current as you'll need for DC once rectified. The Tubecad PS-1 works well. Options make it a bit confusing just take your time. Broskie doesn't respond to emails well. He states in his blog posts he get about 1000 a day. Don't be upset. Par for the course. There are enough people around who have built these things so a support system exists.

Cheers, Steve

PS-1 link: PS-1 High & Low Voltage Regulator Kit