1M-F5 - A 1 MHz F5 project

[jackinnj]

One of my F5's looking into the HP3577a

[triode_al]

Jack,
Nice to see your confirmation of what I saw. I assume top is voltage, lower phase.
Perfect isn't it?
Interesting, you get the same 6/7 MHz bump as I (but I assumed mine was higher, but out of range anyway for my measurement), and thought: it could as well be an artifact.
What output did you use? Which PCB?
albert

[jackinnj]

I think you can make the bump go away by matching the gate stoppers on the JFETs and MOSFETs. The original design just used a 1K resistor and tied the gates together.

I used my own PCB's -- I provisioned them so I could adjust the source resistors on the input stage for lowest THD% It turns out that the 200 ohm pot (P3) is much easier to implement.

[intrator]

We have built a differential version of the B1 Buffer. It sounds very good. Much more detail for the DIY set at

intrator.dyndns.org/Audio.html

[triode_al]

In the past months I have enjoyed my F5.
At times i heard that there was some slew rate limiting. This can be heard with violins or complex symphonics or singing. Either from my Aikido preamp or from my F5.
I have Quad ESL 57's, with a low impedance of 1 ohm virtual at 20 KHz. Hence my choice to implement it. But if it triggers, it hurts the ears. So I took out the limiter function of the F5 by disconnecting the collector legs of the transistors Q4 and Q6.
This gave some more clarity. But not enough.

So I decided to oust the Aikido. I had found that the Aikido is great for pop music and non complex material, but sort of dominated a lot of complex music like classical music. My choice fell on the SP6, for which I had made a test circuit in the past using ECC82 in the first position.
I now settled on the ECC81 and 12.5 dB of amplification and this way I came up with a very dynamic line amplifier. The combo gives an infinite dynamic levels of sounds. Less than 0,01% by the way and able to output 20V RMS.

It surprises me how the F5 shows all the small tinkering of the preamps, of DACs and other active components.

[nar]

Originally Posted by intrator

We have built a differential version of the B1 Buffer. It sounds very good. Much more detail for the DIY set at

intrator.dyndns.org/Audio.html

Nice to see some quality projects on your website dude Especially interconnects

Best,

nAr

[formula 22]

Originally Posted by triode_al

In the past months I have enjoyed my F5.
At times i heard that there was some slew rate limiting. This can be heard with violins or complex symphonics or singing. Either from my Aikido preamp or from my F5.
I have Quad ESL 57's, with a low impedance of 1 ohm virtual at 20 KHz. Hence my choice to implement it. But if it triggers, it hurts the ears. So I took out the limiter function of the F5 by disconnecting the collector legs of the transistors Q4 and Q6.
This gave some more clarity. But not enough.

So I decided to oust the Aikido. I had found that the Aikido is great for pop music and non complex material, but sort of dominated a lot of complex music like classical music. My choice fell on the SP6, for which I had made a test circuit in the past using ECC82 in the first position.
I now settled on the ECC81 and 12.5 dB of amplification and this way I came up with a very dynamic line amplifier. The combo gives an infinite dynamic levels of sounds. Less than 0,01% by the way and able to output 20V RMS.

It surprises me how the F5 shows all the small tinkering of the preamps, of DACs and other active components.

You can give a schematic that preamplifier with ecc82 or ecc81
thank you and cheers!

[triode_al]

Originally Posted by formula 22

You can give a schematic that preamplifier with ecc82 or ecc81
thank you and cheers!

I'll work on it.
Too bad when I made my distortion measurements I did not have my camera at hand.
The basic schema is:
audio research_SP6_schematic1.gif
It took me quite some time to get it under control, I started this time with ECC83 and I ended with ECC801S.
albert

[a.wayne]

Originally Posted by triode_al

In the past months I have enjoyed my F5.
At times i heard that there was some slew rate limiting. This can be heard with violins or complex symphonics or singing. Either from my Aikido preamp or from my F5.
I have Quad ESL 57's, with a low impedance of 1 ohm virtual at 20 KHz. Hence my choice to implement it. But if it triggers, it hurts the ears. So I took out the limiter function of the F5 by disconnecting the collector legs of the transistors Q4 and Q6.
This gave some more clarity. But not enough.

So I decided to oust the Aikido. I had found that the Aikido is great for pop music and non complex material, but sort of dominated a lot of complex music like classical music. My choice fell on the SP6, for which I had made a test circuit in the past using ECC82 in the first position.
I now settled on the ECC81 and 12.5 dB of amplification and this way I came up with a very dynamic line amplifier. The combo gives an infinite dynamic levels of sounds. Less than 0,01% by the way and able to output 20V RMS.

It surprises me how the F5 shows all the small tinkering of the preamps, of DACs and other active components.

Thanks for the update, glad to hear you are enjoying your f5 on the quads ...

[Telstar]

Nice work