Aikido line & phono Guru's advice for a newbie pls

[webby]

Hi All,
I have decided to build an Aikido line and Phono as a front end for a Tubelab Simple SE Amp.
I also have a AT33ptg MC cartridge with the following spec;
# Type: MC type
# Playback frequency range: 15 - 50,000Hz
# Output voltage: 0.5mV (1kHz and 5cm/sec.
# Channel separation: 30dB (1kHz)
# Output balance: 0.5dB (1kHz)
# Stylus pressure: 1.6 - 2.0g (1.8g standard)
# Coil impedance: 17 Ohms (1kHz)
# Direct current resistance: 17 Ohms
# Load resistance: 20 Ohms or more
# Coil inductance: 70 mu H (1kHz)
# Static compliance: 40×±0 - 6 cm/dyne
# Dynamic compliance : 10×±0 - 6 cm/dyne (100Hz)
# Needle tip form: Micro linear (ML)

Can you help me select the tubes best suited to drive the SSE amp?
Do i still need MC step up transformers?
I was going to build the all in one kit, but not sure if I should build the Phono in the same case and share the power transformer.
My priority is sound quality, so if i should just build separately that's fine with me.
I just want to get as much right in the planning stage, so are there any other consideration i should be thinking of?
Many Thanks
Ian

[athos56]

People will say that the external supply is best for sound quality. Since the Tubelab SE doesn't need a preamp you could pick tubes and operating points that keep the gain low (for the line stage). If your going to build a line stage and a phono stage, I think you could do it in such a way that your total gain eliminates the need for a step up transformer. The back of the Aikido manual details the gain of various tubes in each position. See if you can pick the highest gain tubes for your phono stage and then pick the lowest gain tubes for the line stage that still gives you the total gain you need. Then add a switch to put the phono section in/out of the circuit. I'm basically doing the same thing but in a single chassis.

[MarkER]

I am using a combined Aikido phono/linestage into 300B amps into 96dB sensitive speakers. The phono is the maximum gain 12AX7/12AT7 combo into 6CG7 linestage; they have a common B+ supply and separate filament supplies. With a 0.7 mV Ortofon Kontrapunkt A MC cartridge, I can generate enough gain not to use step-up transformers, but only by really cranking up the gain; this brings in tube noise not audible at lower gain. Therefore, I am using Lundahl 1681 mu metal core step-ups and only using about 1/4 of the attenuation, but everything is quiet. You will probably need a dead quiet system (including quiet tubes) to avoid using the added gain of the step-ups unless you have more sensitive speakers or put more gain into the linestage (6922, 6n1P). Just my experience, but transformers provide quieter gain. I also use the system more with an even lower output (0.3mV) ZYX Airy 3 cartridge. Good luck, the Aikido designs sound great.

[athos56]

Yeah, your right, a transformer would still be a good idea.

[webby]

Hey all,
Thanks for the replies so far, very useful. Sound like step up's it is!
I am aided by a friend in the states, he is going to order all the parts then ship to me,Hopefully saving a good few £££'s. I am going to be using Edcor for the iron on the simple SE and this Pre / phono unit. Would Cinemag be a good choice for the step up's, could you advise me on what step up / tube combinations would be a good match.
This would dictate what power transformer to use?
MarkER, Can i ask how you achieved the line / phono combo power supply. The all in one PCB has the psu on it, so I am a little confused with what i need to do?

Many thanks
Ian

[MarkER]

Ian,
One problem with being an early adopter is that I got my linestage board before there was an all-in-one so I had to do the entire power supply. Your job is much easier; you just need an appropriate transformer and hook it up. Because the current demand is low on the phono stage, it is possible to use the same B+; not sure how to exactly connect the two. But the filament demand for the phono is large, so that will need it's own supply. My power supply for both is over at Audio Asylum under MarkER's system and is open for all to view. There are also two views of the board I built it on; still haven't figured out a real enclosure that can handle it all.
Good luck,
Mark
http://gallery.audioasylum.com/cgi/u...rkER&f=general

[GTHICM]

I am in the process of building up the Aikido Phono. I already have a 6cg7 / 5687 linestage that sounds really nice. I purchased the complete kit with the 12AX7 and 12AT7 tube complement. The part quality is just ok, but I would like to consider upgrading the components. Does anyone have some experience having done so, especially MarkeRr, or has anyone contemplated it?

[MarkER]

I wouldn't be too concerned about using designer capacitors. I used the NOS paper-in-oil capacitors for the RIAA and output caps and used the pictured Wima (red) and Phillips (blue) film caps. I really like the Russian PIO caps and may have added a couple from my own stock. I did take the precaution of wrapping the metal covers with teflon tape, then securing the teflon tape with electrical tape to avoid any accidental contacts. Again, I ordered before John was offering the new film caps; if he is offering them, then I am sure they are excellent. I also used the stock resistors (metal film), electrolytics and new production tubes that he offers. The circuit trumps the parts.
The advice to build things stock, then try new things is usually good advice. Let it break in, learn the sound, then see if changing anything improves it.

[GTHICM]

I agree with you, MarkeR, and I also advocate starting off with stock and going from there. I have had good results with Obligatto caps, which are reasonable in cost and good in quality. This approach has worked well with the linestage

Now that you are living with the Aikido, how do you like it and how would you describe what you are hearing? How does it compare with other phono amps you have listened to?

[webby]

Thanks Guys,
I have been searching about on the web for more info and making progress.
If i used a Cinemag CMQEE-3440A step up with my 0.5mv AT33ptg MC and wire the 16:1 I get 8mv output. does this sound correct?
Knowing this how do I choose the tubes / gain for the Aikido Phono pre and intern the tubes for the Aikido line?
To match Simple SE, is there a formula.
Thanks
Ian