jarthel said:
Well, it's a 1:1 transformer, which is what you need to drive high-Z cans if you are building the high-Z Aikido.
Edcor might not be such a good deal if from down under. Hammond also makes these:
http://hammondmfg.com/140.htm
here's the schematic again for reference (and so you don't have to scroll up) http://www.tubecad.com/2006/04/27/aikido_high_impedance_headphone_amplifier.png
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hmm maybe I wasn't clear and I apologize for that.
I am building the high Z aikido. but I want the flexibility of using low Z phones.
I am planning to install 2 headphone jacks. The jacks has a built-in switch. If I insert phones on the 1st jack, these would cut-off the connection to the 2nd jack.
1st jack is for high Z. This is connected directly to the coupling caps which is the 47uF.
2nd jack is for low Z. I was hoping I can use a transformer so I can use low Z phones.
from what I understand and from what you just said, a 600:600 matching transformer is not the right one when driving low Z phones. If so, what transformer would be suitable?
Thank you very much
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hmm maybe I wasn't clear and I apologize for that.
I am building the high Z aikido. but I want the flexibility of using low Z phones.
I am planning to install 2 headphone jacks. The jacks has a built-in switch. If I insert phones on the 1st jack, these would cut-off the connection to the 2nd jack.
1st jack is for high Z. This is connected directly to the coupling caps which is the 47uF.
2nd jack is for low Z. I was hoping I can use a transformer so I can use low Z phones.
from what I understand and from what you just said, a 600:600 matching transformer is not the right one when driving low Z phones. If so, what transformer would be suitable?
Thank you very much
A 600ct:150ct with 32ohm phones connected from center tap of secondary would give 512ohms at primary. Edcor WSM 600/150 $10. Not bad if you can avoid any brokerage piracy on shipping.
Hammond 850C, 600ct:48ct looks nice, if rather spendy. $100 ea.
Hammond 140N, 1500:50 is another possibility. MSRP for 2 units is $37USD each.
Hammond 850C, 600ct:48ct looks nice, if rather spendy. $100 ea.
Hammond 140N, 1500:50 is another possibility. MSRP for 2 units is $37USD each.
Replacing the resistors of front tube with chokes
Hi,
I want to replace the upper and lower resistors of the first tube of Aikido line amp. with the dual coils (340 ohm dcr and 20 H each) of Lundahl 1668 plate choke. Should I connect the coils in phase or out of phase?
Thanks for any input.
Regards,
T.C. MA
Hi,
I want to replace the upper and lower resistors of the first tube of Aikido line amp. with the dual coils (340 ohm dcr and 20 H each) of Lundahl 1668 plate choke. Should I connect the coils in phase or out of phase?
Thanks for any input.
Regards,
T.C. MA
Tweeker said:
I'm intrigued by that schematic. I'm not sure I understand the capacitor divider fully, other than it holds the bottom tube's plate at a constant voltage. Did JB say much about it? Wouldn't those caps be just as much in the signal path as a cap coupled output or parafeed style output?
Sheldon
Am I wrong???
I just want to share my feelings here in respect of the above.
In my last two posts (Post #24 & #25) on this thread, I am asking Tweeker (and others) with respect to the circuit he has kindly shared about the Aikido with Output Transformers (Post #5). The questions that I am asking are pure technical questions to the Aikido circuit with output transformer that he has posted and are never considered by me to be out of topics. Neverthless, I think I can do better by grouping the two posts into one, but as a slow learner, the questions will never come to my mind simultaneously. But I do feel that there are some posters who always think that only the questions that they have posted are relevant, others aren't.
Making a new thread is always easy, but I don't like it and I don't think this is in line with the forum policies: the system will always prompt you to search similar topics before posting a new thread. I can see that some people are too lazy to search before they post. The outcome is: too many threads. I think they have the freedom to do so, but so do I.
Today, I am feeling quite astonished but glad to receive a personal email reply from John Broskie of www.tubecad.com who is busy travelling around but did reply to my such questions in an informative, orderly and courtesy manner. I truly respect such a great, competent and kind person who always like to share his bright ideas with others and respond kindly to some stupid readers such as me.
Just my two cents. PERIOD!
Regards,
T.C. MA
jarthel said:no hijacking of thread please.
in my experience, off-topic replies tend to sway the direction of the topic which usually leaves the original topic unanswered
it's easy enough to create your own
I just want to share my feelings here in respect of the above.
In my last two posts (Post #24 & #25) on this thread, I am asking Tweeker (and others) with respect to the circuit he has kindly shared about the Aikido with Output Transformers (Post #5). The questions that I am asking are pure technical questions to the Aikido circuit with output transformer that he has posted and are never considered by me to be out of topics. Neverthless, I think I can do better by grouping the two posts into one, but as a slow learner, the questions will never come to my mind simultaneously. But I do feel that there are some posters who always think that only the questions that they have posted are relevant, others aren't.
Making a new thread is always easy, but I don't like it and I don't think this is in line with the forum policies: the system will always prompt you to search similar topics before posting a new thread. I can see that some people are too lazy to search before they post. The outcome is: too many threads. I think they have the freedom to do so, but so do I.
Today, I am feeling quite astonished but glad to receive a personal email reply from John Broskie of www.tubecad.com who is busy travelling around but did reply to my such questions in an informative, orderly and courtesy manner. I truly respect such a great, competent and kind person who always like to share his bright ideas with others and respond kindly to some stupid readers such as me.
Just my two cents. PERIOD!
Regards,
T.C. MA
Re: Am I wrong???
Now THIS is really threadjacking on my part...that's to try to curb the sheer amount of repetitive questions on the forum. There's probably one thread/week on "glue for loudspeakers" but only a handful of those threads developed into anything deeper than trivial knowledge.
What you say about threadjacking isn't really true. The *general* policy that the mods apply is that the thread starter be respected as to whether posts not specifically addressing his question be allowed in his thread. So jarthel was in his "rights" asking to avoid threadjacking. All I'm saying is you seem like a good guy so don't get upset.
I'll shut up now to avoid further threadjacking.................
snoopyma said:
Now THIS is really threadjacking on my part...that's to try to curb the sheer amount of repetitive questions on the forum. There's probably one thread/week on "glue for loudspeakers" but only a handful of those threads developed into anything deeper than trivial knowledge.
What you say about threadjacking isn't really true. The *general* policy that the mods apply is that the thread starter be respected as to whether posts not specifically addressing his question be allowed in his thread. So jarthel was in his "rights" asking to avoid threadjacking. All I'm saying is you seem like a good guy so don't get upset.
I'll shut up now to avoid further threadjacking.................
Re: The Tweaker schematic; the two series caps form a voltage splitter (B+/2). Half of the power supply nasties fed in opposite phase to each half of the output transformer where they cancel. As Tweaker says, I personally wouldn't use anything but high quality caps in this position or use alternate splitter means. Sorry if I am restating the obvious.
Thanks, understood, mostly. My post was inarticulate. My question really should have been this: What is the advantage (and/or disadvantage) of having the transformer between the tubes as shown, over just using a series cap to the transformer primary (recognizing of course, that in neither case does the transformer eliminate the cap)? Is it just that the schematic in question has DC on the transformer, which makes the transformer more linear at the zero signal crossover? And, if this is the reason, any thoughts on the relative weight of the possible counter issue, namely large electrolytics directly in the signal path, vs. a smaller film cap in a series cap arrangement? Or is this topology better/worse for noise cancelling than feeding the grid of the bottom tube? Can that divider be left out altogether (this last question is why I put the qualifier, "mostly" above)?
And understood that yes, the power supply is in the signal path for a SE output, but sometimes more than other times. One could have a ccs fed output stage or inductor/transformer fed stage, all of which would isolate PS nonlinearity to varying degrees from the output. In this schematic, the feed is taken from the PS end, so tied directly to those caps. I'm not making any attempt to argue which is better. I'm not qualified by experience or training to do so. But from what I read there seems little doubt that caps have imperfections that can cause some level of distortion. And if the distortion signal is reduced by voltage division, there is less remaining to affect the final signal. JB himself occasionally mentions the capacitor issue in his articles, though he seems less troubled by it than most.
In the TubeCad website, JB gives detailed explanations for his various proposed topologies. I learn a lot by reading those. I was just curious to see what, if anything, he said about this one. Or maybe is was just "you could do this"?
Sheldon
And understood that yes, the power supply is in the signal path for a SE output, but sometimes more than other times. One could have a ccs fed output stage or inductor/transformer fed stage, all of which would isolate PS nonlinearity to varying degrees from the output. In this schematic, the feed is taken from the PS end, so tied directly to those caps. I'm not making any attempt to argue which is better. I'm not qualified by experience or training to do so. But from what I read there seems little doubt that caps have imperfections that can cause some level of distortion. And if the distortion signal is reduced by voltage division, there is less remaining to affect the final signal. JB himself occasionally mentions the capacitor issue in his articles, though he seems less troubled by it than most.
In the TubeCad website, JB gives detailed explanations for his various proposed topologies. I learn a lot by reading those. I was just curious to see what, if anything, he said about this one. Or maybe is was just "you could do this"?
Sheldon
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