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I am collecting parts to build a 2A3 SET amplifier for my Audio Nirvana 15" OB speaker. I'd like to 'future proof' my amplifier build by including an optional line-level cross-over. The idea would be that I could in the future use the same amplifier for a FAST OB set-up. This would mean driving a full-range speaker with the SET amplifier and a supporting woofer with something else, likely solid state.
To get the most out of my investment in the 2A3 amplifier I'd like to cross-over low - hence why a FAST approach and not the traditional 2-way with woofer and tweeter.
There are some obvious constraints - the full range driver needs to be of high sensitivity, at least 90dB. The woofer does not need to be sensitive because it can be driven by a powerful SS amplifier. To keep the size reasonable multiple woofers could be used, e.g. 2 x 12" (e.g. Linkwitz Orion).
This will be a mono speaker for general listening from multiple room locations, so I'd like to have good dispersion characteristics.
Out of interest - which speaker drivers would you consider for such a FAST speaker ?
To get the most out of my investment in the 2A3 amplifier I'd like to cross-over low - hence why a FAST approach and not the traditional 2-way with woofer and tweeter.
There are some obvious constraints - the full range driver needs to be of high sensitivity, at least 90dB. The woofer does not need to be sensitive because it can be driven by a powerful SS amplifier. To keep the size reasonable multiple woofers could be used, e.g. 2 x 12" (e.g. Linkwitz Orion).
This will be a mono speaker for general listening from multiple room locations, so I'd like to have good dispersion characteristics.
Out of interest - which speaker drivers would you consider for such a FAST speaker ?
The 90dB requirement limits it to just a handful of units.
The ones I have personally tested and can recommend are:
1. Radio Shack 40-1197 (FE-103). Very smooth great sound. 90.5dB at 2.83v. You can still get these on line.
2. Faital Pro 3FE25-8, also very smooth and great balance. 91dB. Very inexpensive but great sounding.
3. Faital Pro 3FE22-16, 16ohm good for tubes? Also 91dB and great sounding.
4. If you like high SPL and lots of dynamic reserve but don't mind if upper end is 15kHz only then PRV 5MR450-ndy 8ohm. 95dB.
All of these I would run a 270Hz to 350Hz XO.
Of course there are Lowthers, Fostex EN's etc., Lcao, AN, etc. I have not tried them but some have ragged frequency responses or a big 8dB peak somewhere in 5k to 7k range.
The ones I have personally tested and can recommend are:
1. Radio Shack 40-1197 (FE-103). Very smooth great sound. 90.5dB at 2.83v. You can still get these on line.
2. Faital Pro 3FE25-8, also very smooth and great balance. 91dB. Very inexpensive but great sounding.
3. Faital Pro 3FE22-16, 16ohm good for tubes? Also 91dB and great sounding.
4. If you like high SPL and lots of dynamic reserve but don't mind if upper end is 15kHz only then PRV 5MR450-ndy 8ohm. 95dB.
All of these I would run a 270Hz to 350Hz XO.
Of course there are Lowthers, Fostex EN's etc., Lcao, AN, etc. I have not tried them but some have ragged frequency responses or a big 8dB peak somewhere in 5k to 7k range.
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It's not boom boom - it's pro audio and mid and up only. No bass so has to be used with woofers in FAST. Very detailed ultra low distortion sound. Here is what it sounds like in an OB FAST with a slot loaded woofer complement.
Measurements and sound clips in this thread:
http://www.diyaudio.com/forums/atta...ob-resposne-5mr450-ndy-nearfield-thd-meas.png
Measurements and sound clips in this thread:
http://www.diyaudio.com/forums/atta...ob-resposne-5mr450-ndy-nearfield-thd-meas.png
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XRK971 knows his stuff...But, the RS 40-1197 is very difficult to source these days and the ones that come up for sale are around $25.00 each. Personally I am convert to Faital and PRV, very good products at inexpensive prices.
1197's: There was a German speaker website that has them in stock. They are ridiculously expensive at $70 - but maybe not compared to some modern drivers that don't perform as well in smoothness or sensitivity costing $85 and up. I can't find that link at present.
This is emphemeral just saw eBay listing for qnty 4 1197's for $95.
Radio Shack 40-1197 4" Speakers NOS FE-103 Quantity 4
That's a great deal of they are in good condition. They have fabric surrounds so no need to worry about foam rot.
This is emphemeral just saw eBay listing for qnty 4 1197's for $95.
Radio Shack 40-1197 4" Speakers NOS FE-103 Quantity 4
That's a great deal of they are in good condition. They have fabric surrounds so no need to worry about foam rot.
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I have done a 3 way open baffle with two 12in woofers and a pair of full range TG9FD's for mids and a dome tweeter. It sounds great with a lot of depth and dynamic head room and crystal clear highs. But the complexity and size is a lot more to handle. I found the 2 way FAST OB just as good on most material for a lot less effort. One thing that is nice with a single full range on top is the coherence of the telephone band so imaging and transients are very good as they are phase coherent and a point source.
my five to six watt 2a3 amp built `1993 has sat for over a decade - sounded pretty good with some tube era lps and good lp dubs of 78 - built so whomever wanted to steal stuff might not take. Faital 4fe32 seem a lot more detailed than say pa130. I can have fun now with a pocket sized tpa3116. I need to re-reference the ground buss in this clunker.
There are lots of good choices for mid-tweeter in an OB.
We are not big OB fans, but have used FF85KeN (the new FF85wKeN is better) but doesn't reach 90 dB. Most of the rest of our experiments were single drivers on a big baffle. Our next OB will use A10p (with 2x10: helper woofers) which is near 90 dB.
My measures have this driver at just below 90 dB. These (and all the examples of the FE103 family before the basket change in 2000, ie late 50s till 1999) have a slightly annoying "honk" that lead to the original FE103 phase plug that we developed to cure the problem. Problem most noticable as an "edge" on female vocals.
The 1197 & 1354 were the goto drivers in the late 90s, early 2000s especially after RS cleared them out at $5 each. We probably saw over 100 of the former. Still have some. The much older FE103A were the highly desired version.
The lastest FE103 SOL is an outstanding driver, much better than any FE103 that preceded it. Measures at about 89 dB.
Re the 2A3 SE … when Bernie brought his by, we were fine driving speakers as low as 84 dB (ie EL70) as long as we didn't want to really crank it. High passed you'd be even happier.
dave
Edit: detail added.
We are not big OB fans, but have used FF85KeN (the new FF85wKeN is better) but doesn't reach 90 dB. Most of the rest of our experiments were single drivers on a big baffle. Our next OB will use A10p (with 2x10: helper woofers) which is near 90 dB.
My measures have this driver at just below 90 dB. These (and all the examples of the FE103 family before the basket change in 2000, ie late 50s till 1999) have a slightly annoying "honk" that lead to the original FE103 phase plug that we developed to cure the problem. Problem most noticable as an "edge" on female vocals.
The 1197 & 1354 were the goto drivers in the late 90s, early 2000s especially after RS cleared them out at $5 each. We probably saw over 100 of the former. Still have some. The much older FE103A were the highly desired version.
The lastest FE103 SOL is an outstanding driver, much better than any FE103 that preceded it. Measures at about 89 dB.
Re the 2A3 SE … when Bernie brought his by, we were fine driving speakers as low as 84 dB (ie EL70) as long as we didn't want to really crank it. High passed you'd be even happier.
dave
Edit: detail added.
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Here is what I measured for the 5MR450NDY in an OB. It has a peak at 7kHz, but it's not bad or annoying. A very enjoyable driver as an OB. You could make a notch with passives for it if it bothered you.
Bigun, xrq971,
What about this for a FAST as there is the 2A3 low power : JBL 2426J !
It's a 16 homs, so good for the 2A3 ! It can play in FAST design from around 700/800 to 17 k Hz in a Tratricx ! And the cerise sur le gateau, pardon : icing on the cake : it's a 1" !
Price is the limit... but hey; we are mono here
What about this for a FAST as there is the 2A3 low power : JBL 2426J !
It's a 16 homs, so good for the 2A3 ! It can play in FAST design from around 700/800 to 17 k Hz in a Tratricx ! And the cerise sur le gateau, pardon : icing on the cake : it's a 1" !
Price is the limit... but hey; we are mono here
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I'm not so sure that I want a horn speaker yet, but that one looks suitable indeed for a nice 2A3.
X, that 7kHz peak looks like a full 10dB from valley to peak, how is it not objectionable ? I wonder if my ears are overly sensitive (hyperacusis?) because my experience with the Fostex 127e was that I couldn't bear it and it had something similar in the FR plot ??? I tried to love the Fostex but it very nearly put me off FR drivers altogether. I still would not buy another Fostex without some carefull investigations.
Did you look at the slightly larger but also interesting sensitive 6.5" from Audio Nirvana? It looks to have more FR extension at both l.f. and h.f. http://www.commonsenseaudio.com/an6.5classicspecs.jpg
The FR isnt perfect either but the big nasty peak is pushed up to 10kHz, well outside the 'presence' range.
X, that 7kHz peak looks like a full 10dB from valley to peak, how is it not objectionable ? I wonder if my ears are overly sensitive (hyperacusis?) because my experience with the Fostex 127e was that I couldn't bear it and it had something similar in the FR plot ??? I tried to love the Fostex but it very nearly put me off FR drivers altogether. I still would not buy another Fostex without some carefull investigations.
Did you look at the slightly larger but also interesting sensitive 6.5" from Audio Nirvana? It looks to have more FR extension at both l.f. and h.f. http://www.commonsenseaudio.com/an6.5classicspecs.jpg
The FR isnt perfect either but the big nasty peak is pushed up to 10kHz, well outside the 'presence' range.
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That 7k peak was really bugging me too, so I decided to try the FX120. Glad I did, cause it's a really nice smooth sounding driver.
jeff
If you are using it as a mid-tweeter. Doesn't do bass (an optimum alignment sims at ~110 Fs, 85 F10)
Not useful much below 300Hz in an OB, i'.d guess
dave
From the trough to peak it is 10dB, but take it from middle average level and its 5dB. It doesn't sound bad like a 10dB peak which would indeed be objectionable. I think it's a simple notch filter to smooth that peak passively. Let me see if there is something I can come up with using PCD to smooth that out.
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If it would work with a PLLXO at 300Hz then would it be a better choice than the PRV unit ??
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