DIY SET project - 2A3 vs. 300B

[lynnm]

I am considering building either a 2A3 or a 300B stereo power amp as a winter project. I run KLF30's and would be using the SET amp or amps,(might build monoblocks), in a biamp configuration with my AQ1003 DT or an SS amp for the low end.

If any of you were to build that kind of a setup which route would you go 2A3 or 300B?

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It is meet to recall that the Great Green Heron rarely flies upside down in the moonlight - (Foo Ling ca.1900)

[Deang]

http://www.diycable.com/images/billie_main0.jpg

With the KLF's I can't possibly imagine you actually needing SS on the bottom.

After I put my AE-25 DJH into my system with my RF7's I actually removed the subwoofer from the system.

There is something about the character of tube driven bass that just sounds great all on it's own. Any attempts to "add" to it -- just mucks everything up. At least, that's what I found in my system.

This message has been edited by deang on 09-11-2002 at 10:19 AM

[lynnm]

In the immortal words of Inspector Clousseau ^bemp^

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It is meet to recall that the Great Green Heron rarely flies upside down in the moonlight - (Foo Ling ca.1900)

[Radiohead]

I had to resurrect this post because I am in the same dilemma. I have searched on this forum for a definitive answer but haven't been able to find it. For those who have experienced both...how would you describe the difference between 2A3 and 300B sound? Is one just more watts than the other or is it a completely different sound?

Ryan

[mike stehr]

A average 300b puts out around 8 watts.

A 2A3 is around 4.5 watts.

A 45 puts out about a watt and a half.

They all have there own sonic signature and different brand tubes of the same designation also sound different.

There are different camps of folks who prefer any one of these tubes over the other.

I favor the lowest wattage tubes.

But then you have to factor in the circuit used.

Here's some pics of Jeff Korneff's 45 amps, and a 845 amp.

http://groups.msn.com/korneffvacuumtube

[artto]

The 2A3's tend to sound "sweeter, more subdued" while the 300B will probably have a "clearer sound" & somewhat more powerful bass. All this is dependent, of course, on the specific tube (manufacturer, date of manufacture, etc) & the amplifier design & how it interacts with your speakers and room.

The reason some people want to bi-amp using tubes on the mids & highs, and SS on bass is usually more for "tonal" reasons than for additional power. The SS amps tend to sound more solid, tighter & well controlled, although not as impressive on really deep stuff.

I've been playing bass for over 30 years & I've never really liked tubes for my bass amps, at least not live on stage. Some guys love their Ampeg tube amps. I don't. In the studio where everything is close miked or direct to the board, tube amps seem to sound ok to me. There are also very few tube amps I find acceptable in the lower register for hi-fi as well. To me, most tend to sound somewhat bloated, soft, sometimes kind of "wooly" & worse case, just plain muddy to me although the bass tends to sound fuller and the mids have more "body".

Main "listening" System:

Klipschorns left & right

Belle Klipsch center

Audio Research SP-6C preamp

Luxman MB3045 triode monoblocks (8045G tube based) If anyone knows where I can get some Luxman MB300's...LET ME KNOW!!!!!!!!!!1

Alternate amplification for general use:

Crown PSA2 left & right channels

Crown D150A bridged mono center channel

Crown DL2 Control Center

[mobile homeless]

I am not posting on here too much any more but I will add that I think it surprising that anyone says a 300B has a "clearer" sound than a 2A3. I found the exact opposite.

Also, in my opinion, tubes on bass and guitar give far better tone...If anything, it is only for impact reasons you go with a SS amp. I find the tone universally POOR with SS on guitar or bass.

Call me Mr. Curmudgeon. Heh... I only have two bookmarked forums left..this is one. Please mail me the final cure!

kh

[mike stehr]

Yeah, Audio Forums can be pretty counterproductive.

[leok]

From an engineering point of view:

If you're going to biamp .. don't have way more power than you need, it will make noise, so go with the 2A3.

If you might change your mind and use the SET for everything ..

leok

[NOSValves]

Mobile,

What we all want to know is what is the other forum you still have bookmarked ?? WHo rates as high as us

[mike stehr]

So many Forums....So little time....

[artto]

Well Kelly, you & I obviously aren't hearing the same thing and don't have the same preferences. But, as you know, I have the proper acoustical conditions/listening room to expose the audible differences between just about anything. So I win! . (sorry, just couldn't resist)

Its my "qualified" professional opinion that tube amps, 'GENERALLY', suck for bass amplification, especially in live applications. The tube gear is just too boomy on stage & has to be played too loud in order to cut through the mix. I have a number of old Kustom amps that are SS & have a remarkable tube-like sound, although they don't clip the same (very abrupt). They sound wonderful, by themselves. But on stage, they just don't quite cut it unless you're playing something more akin to background music or need that boom boom bloated sound for something like 50's jump blues. Guitar is something else.

For me, with the kind of music I listen to, and the size of the room, the 2A3 doesn't have quite enough headroom for me. But I'd still like to give them another try, especially since my room is currently being revised to be a little more "live" & I'm finding that I don't need as much power as when the room was stuffed with more exposed sound absorption.

Kelly, since your obviously one of the 2A3 gurus here, what's a good reliable source for some schematics of 2A3 monoblocks? I'd like to build my own. Someone had recommended subscribing to Audio Express but I can't seem to find a proper link for them on the web. These amp manufacturers are charging an arm & a leg, even for kits, for what is basically a hand full of parts that cost only a few bucks. These are all old basic designs. It can't be all that difficult to build.

[Tom Mobley]

here's a link to a few (or more) schematics

check out a few of these, lots to look at.

Tom

[Mike82]

One tube that I haven't seen discussed here is the PX-25. I had the Art Audio PX-25 (5 watt) to drive my old Lamhorns and SAP Quartettes and found that tube sonically superior to both the 2A3 and 300B. It had the most linear sound of any tube I've heard save the 45. Joe Fratus would admit the PX-25 is the best sounding amp in his stable, but being the least powerful, it has limited application. Admittedly, the Art Audio is expensive, but Audion has an affordable PX-25 amp which sounds quite close to the Art Audio version.

[tuber]

If price is a consideration good 300B's go for 3 to 4 times the price of a top of the line 2a3.

When looking for schematics go to your favorite serch engine enter 2a3 schematic, 300b

schematic, etc. I have used Yahoo for this and got more than I could read in a month.

Hope this helps.

[mobile homeless]

Some damn good 2A3 options:

~ JC Morison's Fi Primer

~ A DIYer tackles above

~ My buddy Jean-Francois' Parafeed 2A3

~ Triode Dick's 45/2A3 (in German but you can figure it out

~ Ray Koonce's Time Bandit 2A3

I tossed the same question my friend's way and he said about the same thing with a few additions:

"....I'd try the Micro 3.5 direct coupled from JC Morisson, The Horus (on MagneQuest Site) with a Air-Gapped or Parfeed Outputs, obviously the Moondog, The original Loftin-White, The Baby Ongaku. Most of these will easy show up with a Google search.... "

I linked a good few above. IF anyone is really interested in building the 2A3 Moondogs, drop me a mail and I'll see what I can do.

kh