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Old 29th November 2012, 09:44 PM   #11
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Quote:
Originally Posted by chrisb View Post
To address the original post's question - until I starting having issues with two different P/P EL84 amps that has since been quesstimated as bad rectifiers ( Sovtek 5AR4) and undersized fast blow fuse, I was driving my Castle / Towers with a Tubelab P/P ( Psvane 6BQ5 and 12AT7s- worth every penny as far as I'm concerned) at 12W and a DIY hack-job class A EL84 P/P at about 3.5W - neither ran out of juice for my needs.


I'll waffle a bit with the standard disclaimer "room/music/required SPLs" but I'd hazard a guess that if the MP301 is a real 6.5W of SE bliss, that'd quite probably be fine.
Yes. I would guess the same. My SPL requirements are not extreme.
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Old 29th November 2012, 09:49 PM   #12
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Originally Posted by cogitech View Post
I have pretty-much decided already to buy the Musical Paradise MP-301 MkIII, and I just wanted to run this by you knowledgeable folks to see if you think this amp would be a good match with my EL70 towers.
The extra headroom of a PP EL84 amp might come in handy. You could run in triode for casual listening.

Quote:
Originally Posted by chrisb View Post
To address the original post's question - until I starting having issues with two different P/P EL84 amps that has since been quesstimated as bad rectifiers ( Sovtek 5AR4) and undersized fast blow fuse, I was driving my Castle / Towers with a Tubelab P/P
Is it still "down for the count", or did you get it fixed up?

jeff
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Old 30th November 2012, 12:07 AM   #13
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Is it still "down for the count", or did you get it fixed up?

jeff

Wonderboy was going to bench test again with proper fusing - this one's already been converted to SS rectification - the lack of voltage drop and turn-on surge is likely the culprit. Maybe some thermisters on the HT secondaries wouldn't hurt either - if it's good enough for Jim McShane & Eli Duttman's El Cheapo circuit.... .
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Old 30th November 2012, 12:39 AM   #14
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Maybe some thermisters on the HT secondaries wouldn't hurt either - if it's good enough for Jim McShane & Eli Duttman's El Cheapo circuit.... .
Also good enough for Pete Millett. The DCPP amp has a CL140 right after the diodes for that very reason.

Another option would be to add SS diodes to the 5AR4 plates. That way you would benefit from the tubes voltage drop and not have to worry about reliability.

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Old 30th November 2012, 02:07 AM   #15
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The extra headroom of a PP EL84 amp might come in handy. You could run in triode for casual listening.


jeff
Well, I am really only assuming that my SPL requirements are not extreme.

I am running my SPL meter right now with the volume as high as I reasonably ever might have it.

Listening to Adele (live, acoustic), 12 feet from the speakers, SPL hitting 98.6dB.

Will a small tube amp keep up?

EDIT:.....David Bowie just kicked in and this volume level is too much for me (or maybe it is the Raytheon tubes I just stuck in the B283). Anyway, peaks of 99-100 dB at 12 feet are about as extreme as I get. David Bowie (China Girl) hovering around 80dB peak at 12 feet is comfortably loud and very, very cohesive...

Last edited by cogitech; 30th November 2012 at 02:18 AM.
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Old 30th November 2012, 02:33 AM   #16
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Barenaked Ladies... and the Mullards are back in the B283. I just can"t do the Raytheons for very long. 85dB-ish peak at 12 feet is very comfortable with these tubes. Could probably push it more before it gets unpleasant.

Just trying to give you all a sense of my SPL expectations...
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Old 30th November 2012, 04:37 AM   #17
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Listening to Adele (live, acoustic), 12 feet from the speakers, SPL hitting 98.6dB.

Will a small tube amp keep up?
Not a chance at that distance. At those levels, your Yamaha is probably getting close to it's rated output.

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David Bowie (China Girl) hovering around 80dB peak at 12 feet is comfortably loud and very, very cohesive...
At that level, a small amp would be fine. You'd only need a couple of watts. Bump that up to 90dB, and you'll need 16 watts to produce that peak. Every 3dB increase, you'll need to double the power.

It sounds like your B283 buffer is adding a lot of distortion.

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Old 30th November 2012, 04:45 AM   #18
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Not a chance at that distance. At those levels, your Yamaha is probably getting close to it's rated output.
A quick back of the hand calc, and giving some benefit to the doubt to room gain, the Yamaha is clipping at those levels.

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Old 30th November 2012, 04:54 AM   #19
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You're right, but I was trying to be generous.

BTW Dave, Ken dropped by today and picked up your MarKels.

jeff
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Old 30th November 2012, 04:58 AM   #20
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He phoned me so i knew that... thanx.

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