Cathode Follower Pre-Amp

[Richard]

Cathode Follower Pre-Amp

Many members are experienced builders. Please think back to your earlier days of knowledge and ability and vote as you would see fit for the future direction of WD. This may be slightly different to your own requirement today.

Rich

[NealG]

I would say yes. Many tried the CF conversion of the WAD PreII and found it more to their liking, may not suit all but it's easy to implement and can be made cost effective.

[NickG]

I am not convinced that a CF would be the best choice, but I would certainly say a active pre should be in the range, a aikido (for example) might be interesting.

[david counter]

I would vote for a Aikido pre amp

[beelzebub]

Just my thoughts...
The Aikido pre certainly appears to perform well (from John Bronskie's measurements), but do we need this much gain these days - the Aikido gives roughly 1/2 the mu of the triode in the first stage, so even low mu valves may give the "full volume at 9 O'Clock" problem. My WAD 6550 integrated and my AMP3 class-D both clip on full volume with only a pot between source and amp. Matching source and destination resistance, and driving long cables seem to be the main reasons for active preamps these days (and being otherwise as invisible as possible). There was (is?) a thread on unity-gain preamps on the diyAudio forum that has some interesting ideas.
What are your experiences?
Regards,
Jim

[leo:)]

I'd like a nice valve pre so any suggestions would be great

[Global]

It would be good if a design could be achieved which had switchable or configurable gain and perhaps an option to take output from a CF or direct.

[A Stuart]

Forgive my ignorance.
It might be beneficial to more than just myself if someone could explain in a nutshell , or point me towards, what are the desirable (or otherwise) attributes of a cathode follower.
The same would apply to the other suggestions for new kits.
I could be totally wrong but suspect most kit builders (= future WD customers) look on it as a once in a lifetime extravagance and are not, until hooked, compulsive serial builders with encyclopaedic knowledge.

[NealG]

High input impedance, Low output impedance, very linear, simple cct to implement. Can drive long cable runs and, depending on valve, drive high capacitance cables.

Downside, less than unity gain IE typical .95 gain. Uses 100% negative feedback and some say its veiled sounding or slightly 'thick' sounding.

IME it works well and I'm sure some of the negative comments re. sound quality are down to valve choice, partnering kit or implementation.

CF fans will find this interesting Cy Brenneman cf single ended output amp, Bruce Edgars favouite builder.

http://www.enjoythemusic.com/magazin...sbrenneman.htm