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What tubes for sibilant SET Triode amp

I have recently bought a Cayin/Spark 9021DEX amplifier. This is a zero feedback SET design in which I currently use the original Chinese made 211 output tube a 6SN7 GTB by Sylvania as a driver tube and a late Siemens ECC88 at the input. The bias on the output tube checks fine the sound is great with a minimal tendency to sibilance. As I am going to buy a set of back-up tubes anyway - which tubes to buy to get rid of the tendency to sibilance? Opinions seem to vary considerably! Any suggestions??

Preamp is a MacIntosh C220, Speakers are Gallo Ref 3.1 and Analog Front End is a VPI Superscout with a Shelter 90X.
hanshhh

Showing 2 responses by dekay

dekay's avatar
dekay
5,716 posts
 
Start by changing the input tube.

If you want a rich/full 3D sound try Amperex solid dimpled disc getter 6dj8. Mullard made one as well (with a "G" factory code I think).

Slightly less full, but just as good is the Amperex Orange Globe label 6dj8.

These are much less expensive than similar sounding e88cc's and they work fine as an input tube (used them in an Audion Silver Night 300B).
dekay's avatar
dekay
5,716 posts
 
I didn't realize that you are Switzerland based.

Add Philips Miniwatt 6dj8 to the list as they should be fairly common on your Ebay.

I'd also like to note that using Siemens 6922 types in my old Audion (300B/5687/6922) amp caused sibilance, therefore my experience differs from that of Ralph @ Atmaspere.

80's Mullard CV4024's (used as drivers) make my current 2A3 SET amps sound like a cheap transistor radio. Telefunken 12at7's make them sound too bright.
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