suitable preamp for a tube amp (kt88+12ax7)

[kevinkuang]

Hello, I am totally new for tube amp. Just brought a tube amp 40wch, with KT88 + 12AX7. I really don't know how to choose a "suitable" preamp for it. What makes a preamp good? Should I look for tube preamp or ss preamp? what's their difference? My budget is $300-$500 (for used). Thanks for input

[Sherman]

Originally posted by kevinkuang
Hello, I am totally new for tube amp. Just brought a tube amp 40wch, with KT88 + 12AX7. I really don't know how to choose a "suitable" preamp for it. What makes a preamp good? Should I look for tube preamp or ss preamp? what's their difference? My budget is $300-$500 (for used). Thanks for input

I think for your amp any good preamp with a gain of 4 to 6 would probably work just fine. You need to decide on what features you want/need such as input selectors (some may have only a single set of inputs), phono stage (rare these days as a built-in feature) etc.

If you are looking to build one yourself the Bottlehead Foreplay kit would be a good choice. A ton of them have been built and there is a large community of builders/users to turn to for help and ideas on mods.

Also Lighthouse Electric has a suitable preamp kit the STA-1LG for about $100. With the LE kit you have to supply the chassis. I built one this winter and it had a fairly annoying 60 Hz hum but I converted the heaters to DC (not a bad idea for a preamp anyway) and the hum is gone. It now drives my KT88 SE monoblocks quite nicely.

[kevinkuang]

should I look for tube preamp or ss preamp for the KT88? thanks

[Sherman]

Originally posted by kevinkuang
should I look for tube preamp or ss preamp for the KT88? thanks

Yeah, not very specific about which was best was I? But honestly it depends on whether you intend to build or not. If you want something already built you have a lot of options but not quite as many as if you will build it.

The "tube sound" will still be there if you use a SS pre but I just like the idea of tubes end to end. If I were you I would build either the Bottlehead Foreplay or the Lighthouse Electric STA-1LG.

[kevinkuang]

how important is the preamp in the whole system? will a good or bad preamp make how much the sound better or worse? thanks

[Sherman]

Originally posted by kevinkuang
how important is the preamp in the whole system? will a good or bad preamp make how much the sound better or worse? thanks

That actually depends a lot on the power amp and how much gain you have to get from the preamp in order to drive the power amp. A bad preamp can make a good power amp sound bad but a good preamp can't make a bad power amp sound good.

I would say one of the most important things a preamp can do (or actually not do) is hum. Any hum from the preamp will be amplified by the power amp so it is important to have a quiet preamp. Most power amps don't require a lot of gain from a preamp, so a preamp with a gain from unity to maybe 6 should be fine.

Another function of many preamps is input source selection. If you regularly listen to more than one source (I use a tuner, CD player and turntable) it is nice to be able to switch between sources without having to change interconnects around.

[dshortt9]

Here is a quick suggestion:
http://cls.audiogon.com/cgi-bin/cls....ube&1115915942