Need Recommendations For Adding Tone Controls To SET Amps.

[Benesesso]

I'm running a pair of 1970's Klipschorns driven very nicely by Wright 2A3 SET amps and a Wright tube preamp. I added the 1.0uF caps. to the AA crossovers ala Al. Kap's advice. They extended the high end noticeably (big improvement, thanks Al !).

Very happy with the sound on most CDs/DVDs, but some of them are recorded with a lot of high end, and the sound is just too bright for me (69 year old ears).

I think I need to add some kind of tone controls so I can reduce the treble a little on these hot recordings--the bass is fine. Not looking to spend a bunch for this. Is a cheap, switchable-out graphic equalizer a good method, or is there a better way?

Thanks.

[tube fanatic]

A graphic equalizer will probably ruin the sound of your system. I'm not familiar with the x-over mods that you made, but your comment suggests that the high end frequencies were accentuated after making the change. It might make sense to do a switchable arrangement with some different capacitor values to create a high frequency shelving control. I don't believe that Wright uses any kind of negative feedback in their triode designs (not sure about this, however). If they do, however, it would be fairly easy to implement a variable feedback feature and use that to shape the high frequency response of the amp to suit the program material. I've done this with many of my pentode amp designs and it works quite effectively (I don't use any feedback in my triode designs as a general rule). Hope this helps you a bit.....

[Benesesso]

Thanks. OK, no graphic equalizer. The added capacitor works by removing unwanted frequencies which are below what the tweeter can handle, and allowing more of the high freqs. to reach it. Al Kap. on this forum has commented and run a lot of computer tests on the idea, and attempted to explain it in simple terms such that non-electrical guys like me can get an understanding of the improvement of the sound of a Klipschorn. I'll never understand HOW it works, but it does. MOST of my CDs/DVDs sound better, but some of my favorites are just too bright.

I temporairly disconnected the SET amps and am using an old Yamaha SS integrated amp. which has tone controls. On those bright recordings all I have to do is cut the treble by one or two clicks, and of course the Yamaha SS doesn't have the super-clean sound of the SET's, even with the tone controls set at neutral. Guess I need a tube preamp that has tone controls built in. Time for an internet search.

[bkrop]

I have wright 2A3s and klipschhorns also, I am running a vintage scoot 130 pre with them that has been rebuilt by NOSvalves. I like the phono stage and can't live without tone controls to change individual recordings. If the tonal shortcomings are generalized among most recordings people now compensate by using different interconnects to shape the sound since most new pres don't have tone controls. Room treatments are also an option. Good Luck!