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I have Searched and researched in lots of places, but...What I'm thinking about is using a 45-based SET, mono or stereo, on the tweeters of my DIY OB LA speakers. I'm using 22-Watt ASL 845s on the MR and have determined that I sort of never use more than a few Watts from them. Therefore I'm considering buying a Music Reference 6EM7/13EM7 SET for that; its about-3-Watts ought to be plenty. Then the 1 Watt or so from a 45-SET ought to be plenty for the treble. I've looked at the bottlehead Paramour IIs and the ASL Tulip; both are 2A3-based amps that can use 45s. Since OPTs and power transformers for 1 Watt per channel ought to be less expensive than those for 3-Watt amps, I'm hoping to find something in the $500 - $750 range. Altho I've done plenty of modding of electronics over the decades, I do NOT want to scratch-build an amp, but kits would be plenty fine.
Anyone? PLEASE include links; it took me 15 minutes to find Jeff Korneff's site last nite and I still didn't find any product info.
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Tin-eared audiofool and obsessed landscape fotografer.
http://community.webshots.com/user/jeffreybehr
Follow Ups:
actually, one of your premises is off- thinking you that you can get by with a cheaper output xfmr because of your needs. It's no secret the Bottlehead Paramour in stock form uses a very inexpensive output xfmr to keep the costs low for people to experience the sound. I don't think you could find one less expensive, if your goal is to save money that way. However, the stock output xfmr is very good in mids and trebles; the upgrades mainly give more bass. Since you don't need bass, you'd be getting what you wanted in the stock kit. YOu could also get good advice on the Bottlehead forum for adjusting the frequency cutoff to avoid even loading the xfmr's with the unneeded frequencies.
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Tin-eared audiofool and obsessed landscape fotografer.
http://community.webshots.com/user/jeffreybehr
here's a link about their output xfmr- as someone said below, the kit is an excellent value for the parts alone- the cost is as low as it is because it's an excellent circuit and they've worked very hard to source bargains like this that give outstanding performance. They've found the price points for everything you can get by with and still have great bang for the buck. I doubut if you'd find another xfmr that would handle mids and highs better for <$10!
Be patient and troll ebay and audiogon. 45 based amps come up all the time in the 400 to 600 dollar range, usually pretty decent DIY efforts, but it might take a while to find them.
I use a Korneff 45 on series strapped Aurum Cantus ribbon tweeters. Crossed over at 3500, the 45 tube is probably just about the best tweeter amp there is, incredible immediacy and tonal character added to the soundfield. 300b's are also excellent, but mostly to render space, they don't have the timbral excellence of the 45's in the same spot. I have never heard a 2A3.
Above 3500, the tweeters use only 10 to 15 percent of the total audio output, so if the tweeters are 90db efficient or above, a couple of watts is overkill.
Wait for the 45 it's worth it!If you email me I can provide you with a parts list and a ppt file on a really good 45 amp.
Same as a kit, you just have to buy the parts, which is a good thing as most kits have to skimp on expensive parts to cut costs.
The amp can be built in the $450-$700 range depending on how boutique you want to get with the trans and other stuff.
Simple build, even I could do it, with help of course from a guru!
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Tin-eared audiofool and obsessed landscape fotografer.
http://community.webshots.com/user/jeffreybehr
My tweets are the far-less-expensive $30 Daytons, and a month or so ago, I gave up trying to make them sound acceptable and reverted to a single softdome tweeter for a while. But then I learned the B/MR drivers require an at-least-2nd-order LP filter to get rid of their harsh-sounding treble, so I went digital with a dbx DriveRack PA speaker-management system. I'm now using 4th-order L-R filters at 2800Hz for both, and the system sounds MUCH better and in fact very good. I've had this SMS for only a few days, and I'm the kind of audiofool who sometimes needs a week or 3 to determine flaws, so we'll see...or hear.
Based on your comments, I guess I really should wait for a 45-based SET; I'll keep looking.
But I sure am tempted by a pair (= 4 channels) of Music Reference 6EM7/13EM7 amps.
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Tin-eared audiofool and obsessed landscape fotografer.
http://community.webshots.com/user/jeffreybehr
When I started looking for tweeter amps, i thought on theory that a transistor amp would be best because of specs and above 3Khz, how could it matter? I was so wrong, although all of the amps did a decent job. I still don't know why a tweeter adds so much to the rendition of the spatial presentation.
Class AB transistor: dry, dusty, and flat
Class A transistor: better tone and lustre, but still flat and a little glarey
Class A push pull Baby Sophia: much better space and tone
Fox ASL 6c33 SET: dramatically better space, a but the tone not that great
Agape 300b: Like the spice from the Dune fantasy, opened up space, tone and timbre to make a nice psychidelic breakfast, but lacked some immediacy and lustre.
Korneff 45: not as much space as the 300b, but a lovely melting sheen and texture to the tonalities and authority, like "this is THE tone, accept it."Another good option is a single ended tube rectified el 84, which I use on the tweeter of my center channel when it is in operation. It probably falls somewhere between the 300b and the 45, although a 300b does that space thing so well. These can be had really cheap, I got a pair of Akai mono pulls from the old tape decks and they sound wonderful both full range and as tweeter amps, $150 and they can be found for half that. They also have a little more power (5 watts) if you are using very large arrays ot tweeters in series.
...for the Paramour IIs they would sell me?
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Tin-eared audiofool and obsessed landscape fotografer.
http://community.webshots.com/user/jeffreybehr
Yes, of course. Bottlehead has the plans, parts list, and assembly manual for sale - we even throw in the actual parts as well.The design is not in the public domain, and I have not licensed the circuit to anyone except Bottlehead.
If so it would be cheaper. I might very well end up with a 45 for a tweeter amp too. So with that in mind could you give me a breif run down of the high frequenhy advantages behind parafeed? I understand it's advantages for bass.
"So with that in mind could you give me a breif run down of the high frequenhy advantages behind parafeed? I understand it's advantages for bass."Russ, as I understand it they are one in the same. In a nutshell, without the gap there is no need for more winds to keep the inductance up. Without the extra wire there can be less capacitance.
Somebody please tell me if I'm wrong.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
...all the parts. :-)Do you know if bottlehead will sell that stuff?
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Tin-eared audiofool and obsessed landscape fotografer.
http://community.webshots.com/user/jeffreybehr
about your desire to attempt to buy someone else's intellectual property from someone who doesn't have a license to sell it and w/out paying anything to those who do. I'll say that much for you. What are you planning to do with it if you get it? just curious.
I think all of us in this hobby should try to protect the ones who supply it, and try to make sure they can make a living and support their families, so they're able to eat, etc. and be around for us. I don't think anyone of them is making such a grandiose profit that anyone can even begin to rationalize ripping them off.
Best to ask Doc B directly - it's his business.
For a bit less than 350 per amp you are getting a 12at7, a 2a3, an output transformer, a power transformer, a plate choke, a parafeed cap, and a CCS kit as well as the chassis/jacks/resistors/caps/tube sockets.Without putting a price on Paul's engineering time and the excellent instructions I don't see how you can source the parts for less. Besides, great folks to do biz with and the best support around!
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