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kevin gilmore

transconductance amp

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I could probably be into trying one of those with my orthos. See if it can unseat the DynaFET...


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1 hour ago, Pars said:

I could probably be into trying one of those with my orthos. See if it can unseat the DynaFET...


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I have my doubts about that ... However, the interesting thing (for me) is to try it.

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First, thanks to Dr. Gilmore and Soren!

My amp is working and everything is OK. It's perfect with low impedance and miserable sensitivity headphones. 

B: +/- 29Vdc

~2.1/50=41mA (L) 43.2mA (R)

~2.2/562=3.7mA (L) 3.9mA (R) 

Voltages are a bit lower than Congo5 but I think it´s correct.

I start working on the chasis now. I´ll install a switch to select the gain as I did in the SquareWave.

P.S. I know I have to put a photo to fulfill my part of the deal. I'll place it this weekend. 🙂 

 

 

Edited by jose
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After 1 hour voltage on 562r fall to 1.9Vdc.

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This was completed an hour ago.  It worked though I did not do any measurement.  I tried it with my only planar Hifiman HE6.  The volume was a dummy.  I used a preamp.  I could not afford a decent volume control for individual headamps.

e21e0bdc-d132-4afb-80ff-e1aba2b21f07.jpg

Edited by samsie
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Find "currentsource" here

I´m working on a F2J. It will be very interesting. I had not had any experience with this type of amplifier until now.

I don´t think that it´s a "definitive amplifier" (I'm in love with the balanced Dynahi) but as an alternative it's not bad for the planars.

 

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9 minutes ago, jose said:

Find "currentsource" here

I´m working on a F2J. It will be very interesting. I had not had any experience with this type of amplifier until now.

I don´t think that it´s a "definitive amplifier" (I'm in love with the balanced Dynahi) but as an alternative it's not bad for the planars.

 

Thank you very much sir, thats one big treasure of schematics:rolleyes:

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Just now, A_Zero said:

Thank you very much sir, thats one big treasure of schematics:rolleyes:

You have to thank Dr. Gilmore and everyone who has worked on it.

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On 2/29/2016 at 10:39 AM, wink said:

More realistically 2.27/35 = 0.0649A = 64.9mA.

 

Please guys, could you explain this to me?

I understand that 2.27volt. goes through 50r. Why replace it with the impedance of the headset?

Gain selector is quite a hit. I'm enjoying it enough!!! 

F2J and the KG Transconductance Amp have a very similar behavior; they shine with impedances between 30r to 75r from there they lose a lot.

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