Tube amp for active tweeters

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chrisss

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Tube amp for active tweeters
« on: 24 Feb 2015, 03:15 pm »
Hello,

I am looking for a low watt tube amp to drive a pair of high sensitivity compression drivers from 450hz and up.

Any recommendations, ready made or diy, are welcome

Thanks
Chris

kentajalli

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Re: Tube amp for active tweeters
« Reply #1 on: 1 Mar 2015, 12:27 pm »
If you had said 2KHz or higher, I would have said any low power amp would do, since there is not as much energy beyond this point, you could even use a triode amp.
But from 450Hz, little-poweramp may not do.
How big is your bass amp?
What's the min/max impedance of your tweeters?
If the tweeters are high impedance, consider using a OTL amp, no transformer means cleaner treble (I can vouch for that)

chrisss

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Re: Tube amp for active tweeters
« Reply #2 on: 1 Mar 2015, 04:49 pm »
Compression drivers are rated 111db/w with 16ohm impedance.
Because they will be dsp actively driven, I wouldn't feel safe with an OTL.. (or maybe I'm wrong)

What would you think of this for example? Parafeed 6dn7 spud
http://bottlehead.com/s-e-x-2-1-specs/


Bass amp is a classd Hypex ucd400

kentajalli

  • Jr. Member
  • Posts: 49
Re: Tube amp for active tweeters
« Reply #3 on: 1 Mar 2015, 09:52 pm »
Your poweramp is rated at massive 400W right?
if I read the link you sent correctly , that sex amp is a headphone amp primarily.
I don't know, I am out of my depth about what speakers and configuration you are using.
But again, generally 450HZ upwards, is most of the audible bandwidth, even with a 110dB sensitivity unit, I think you need a topnotch, extremely quiet (hiss wise) amp with a few watts atleast.
Just because the unit is rated 16 Ohms, it does not mean it is that all the way through the bandwidth.
You should not be scared of OTL amps, I have used one for over a year now, but if you only need a few watts, go for a single ended (triode) amp.
What's your budget?
A single ended EL84 based amp should give about 3 to 5 watts of clean output.
Since your bass amp is a module, are you sure you want a tube amp?
Pickup a quality transitor amp from 70's or 80's from ebay, if they do not output bass, they do a very good job of  higher frequencies.
Meridian 103's or sugden A21's in good condition would be fine. 

shooter

Re: Tube amp for active tweeters
« Reply #4 on: 1 Mar 2015, 10:51 pm »
If you can DIY how about a SE VT-25 with Permalloy output transformer custom wound to roll off at the frequency you desire. My friend has one built this way sounds wonderful.

chrisss

  • Jr. Member
  • Posts: 3
Re: Tube amp for active tweeters
« Reply #5 on: 3 Mar 2015, 07:26 pm »
Thanks for your recommendations

@shooter
That sounds really attractive. I have considered this type of dedicated OPT, but it is very hard to find a transformer vendor with actual experience in such customary work.
I would be most interested in this amplifiers schematic, and the output transformer manufacturer.