Aikido and output transformer

jarthel · 14th July 2006, 12:20 AM

I am thinking of building one of this: http://www.tubecad.com/2006/04/27/ai..._amplifier.png

I am wondering if the output caps can be omitted if I use an output transformer.

Thanks for the help.

leadbelly · 14th July 2006, 02:00 AM

Quote:

Originally posted by jarthel
I am wondering if the output caps can be omitted if I use an output transformer.

Yes. Proponents of iron for DC blocking claim fine iron beats the sound of fine caps. Can't verify that position yet but I plan to try it out with my Aikido boards.

jarthel · 14th July 2006, 02:03 AM

Quote:

Originally posted by leadbelly

Yes. Proponents of iron for DC blocking claim fine iron beats the sound of fine caps. Can't verify that position yet but I plan to try it out with my Aikido boards.

can you suggest an output transformer from the hammond range that is suitable for the aikido headphone amp? thank you

martinab2 · 15th July 2006, 05:43 PM

Can't see how you could use an output transformer with the aikido circuit other than in a parafeed (capacitor coupled) arrangement which would be a bit pointless in this case since you would still need the output caps

Tweeker · 15th July 2006, 06:42 PM

Requires an airgapped OPT, so Im not sure low end iron will beat capacitor coupling of similar cost. Consider using oil motor run capacitors for budget coupling caps as another alternative. From correspondence:

leadbelly · 16th July 2006, 03:17 AM

Thanks for correcting me. I was thinking of the attached schematic and thought that the capacitor was only needed for DC blocking for the High-Z output. I also thought non-airgapped transformers were suitable for this service if the DC current was low enough, but it sounds like that's not the case.

Tweeker · 16th July 2006, 06:07 AM

Fine iron may well beat fine caps, but, there are many fine iron proponents who dont feel Hammond quite qualifies. Also, finding an OPT whos DCR will set the bias for an optimal operating point may be tricky.

Geek · 16th July 2006, 07:09 AM

*cough*Edcor*cough*

This one looks useful.

leadbelly · 16th July 2006, 06:03 PM

Quote:

Originally posted by Geek
*cough*Edcor*cough*

You guys are confusing the bleep out of me. Why would you put in a 1:1 transformer if you still need the cap to block DC? I could see using the 10K/150 or 10K/600 to drive low-Z headphones.

zix · 18th July 2006, 10:42 AM

I can´t do the math, but to my eye the circuit first published would seem to work nicely with a Lundahl 1660SE/18mA. Is there something that would make this a bad choice in the Aikido output stage?
Edit: and the second one would do witout a coupling cap, if you don't need the high z output.

14th July 2006, 12:20 AM	#1
jarthel diyAudio Member Join Date: Jan 2002 Location: somewhere in Australia	aikido and output transformer I am thinking of building one of this: http://www.tubecad.com/2006/04/27/ai..._amplifier.png I am wondering if the output caps can be omitted if I use an output transformer. Thanks for the help.

16th July 2006, 06:07 AM	#7
Tweeker diyAudio Member Join Date: Dec 2004 Location: Cincinnati, Ohio	Fine iron may well beat fine caps, but, there are many fine iron proponents who dont feel Hammond quite qualifies. Also, finding an OPT whos DCR will set the bias for an optimal operating point may be tricky. __________________ Be sure your foil hat has a good low impedance ground.

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15th July 2006, 05:43 PM	#4
martinab2 diyAudio Member Join Date: Mar 2004 Location: aberdeen, uk	Can't see how you could use an output transformer with the aikido circuit other than in a parafeed (capacitor coupled) arrangement which would be a bit pointless in this case since you would still need the output caps

16th July 2006, 07:09 AM	#8
Geek diyAudio Member Join Date: Sep 2004	coughEdcorcough This one looks useful.

18th July 2006, 10:42 AM	#10
zix diyAudio Member Join Date: Jul 2003 Location: Sweden	I can´t do the math, but to my eye the circuit first published would seem to work nicely with a Lundahl 1660SE/18mA. Is there something that would make this a bad choice in the Aikido output stage? Edit: and the second one would do witout a coupling cap, if you don't need the high z output.