Mikael Abdellah SE KT88 ideas and questions

[kacernator]

Hi,

I am planning to build stereo version if this schematics: http://www.diyaudio.com/forums/attachment.php?s=&postid=671676&stamp=1119993206

I am planning to make it fixed bias.

Can I use ECC88/6DJ8/6922 instead of 6N1P without any modifications?

Would using the cathode follower give better sound? From my own experiences, feeding from cathode followert hte sound is more compressed but also more focused and punchy instead of feeding from anode.

Thank you.

 

[porkchop61]

I just built a stereo (dual mono) version of this amp and am very impressed with the sound.

From what I've read, you can use the ECC88/6DJ8 without any modifications. I've been meaning to try this as soon as I buy an ECC88 tube.

I don't think you can drive the KT88 with a cathode follower, after all a cathode follower only has a gain of around 1. Others will know more about this than me though.

Good luck on your build, I think you will be very happy with this amp.
Glenn

 

[kacernator]

I meant keep the first gain stage as it is in original schematics and add after this stage the cathode follower. So you need whole one tube for one channel.

I have just ECC88, no 6N1P, so I hope ECC88 will work.

 

[Simpleton]

The ECC88 works with the resistor values for the 6N1P without a problem. I've been running mine that way since I built it and it sounds great, with enough drive for the KT88.

 

[kstagger]

if you want to try 6N1Ps - they are dirt cheap and sound good too.

I've been looking at this design and wonder why there isn't some loop feedback - at least in UL mode I would expect a high output impedance. What kind of speakers are you guys using with this?

 

[porkchop61]

This amp sounds good on my Altec A-7's
I mostly use it on my Yamaha bookshelf speakers though that are rated at 89db and I only run the volume controls at about 50%.
The Altec's are too big for the living room, and have a very low WAF.

 

[kacernator]

I havent build this amp yet, but speakers 90dB and higher will work very good.