...hi All :D

I'm really not ready to start thinking about amplification right now...but I think I had better start thinking about it.

Here's my story. I will soon be done with some speakers I'm building...and the speakers will need to be bi-amped.
I have two restraning factors...I am almost out of money for audio products right now (but I will save up more :) ) and I don't have a ton of room on my rack for large or huge amps. I have one shelf for the mid/tweet int. amp...and one for the bass amps.


the speakers. The speakers are going to be bi-amped...with the mid/tweet being powered by one amp and the bass being powered by another.


The mid is a JBL2441 attached to a 650Hz round EdgarHorn horn...this will be crossed at 800Hz. The tweeter is a Fane 5022 which will be crossed at 10kHz. The total sensitivity for the tops will be 106db.
The bass cabinets are a 6cuft sealed enclosure housing a TAD (pioneer) 1601a 15" woofer. The sensitivity for the woofer is rated at 97db...but I have heard people say it is more like 95db.


I am thinking I may want to go with something 45 based on top...I am not opposed to building an amp either...although I would need someone to help me along the way. SAme with vintage gear...I'm not opposed...but would need some direction.


Any suggestions you can give for what amps to use would be great. If you can also give reasons why you like a particular amp for a given application that would be great too!

Thanks in advance!

GF,
Something wrong with the Cary's? If not a simple change of the filament transformers will let you go 2A3 and 45, and you can get some TJ 2.5Volt 300B mesh plates.
Things are working well with my amp at the moment but next time I go under the hood I am going to check out the filament transformer and see if it has a 2.5 tap on it. If so then later I will be able to roll some power tubes by just changing one solder connection.
I just posted an interesting site on caps in DIY that has some very insightful info on parralleling Polys with the Electros so if you have a SRPP like I do I know you can beef and or upgrade the Elecros, put in some good polys like Wimas(what I used) on your VT-229s.
I have some RCAs and love em!

Thatch...nothin' wrong with the cary's. But I really think they would be better left as a Cary300se. I would rather sell them in their original state than start goofin' around inside there. I just fear that once I change the Cary amps...I wouldn't be able to get anything for them if I sell them.

:dunno:

Fish -

What is your budget for both amps? You know what I think, put the bulk of your monies into a decent 45 amp for the mid / tweeter. If I haven't clarified myself, or you haven't followed my "Moth thread". The 45 tube alone, and not the SET topology alone, is what has made the greatest difference. Put a 2a3 in my SET amp and it is NOT the same thing, least for me. Put a 45 in there and it is, for lack of a better word, MAGIC. Not a great difference, or perhaps outside the relm of sonic significance for some, but one that for me either brings EVERYTHING together or puts My system over the edge; transforming it from a mere replay device to one capable of organic pleasure. YMMV, and all that crap.

Check out the Doc "Bottlehead" 45 specials that may or may not be available. Someone said, that "the 45 tube is hard to screw up". I'm inclined to believe that. http://www.audioasylum.com/scripts/t.pl?f=set&m=11966

MikE

Hey MikE...I have been readin' yer moth files ;)


I have heard a couple DIY 45 amps including the Jeff Korneff 45 , with and without his preamp too...very nice sounding!

As for your comments about the 2A3...many do like the 2A3...I am just not one of them...The 45 set and the 2A3 tubes have a very different sound...really nothing to compare...other than some amps allow you to drop one or the other in...they are quite different.

How much money??? :dunno: dunno. I may give Jeff Korneff an e-mail to see what the price would be for one of his 45's. If I go this route...I'll have to sell the cary's and Joule for sure. I think this is the direction I'm headed in...but I'm just a bit reluctant to start the process.

take care>>>>>>

Well...looks like I'll wait until the speakers are done (which I did plan to do). After that time I'll try to experiment with a couple different amp configs.

http://groups.msn.com/korneffvacuumtube

hopefully soon enough :)

... for the link to Jeff's page. Interesting stuff. Based on Jeff's comments looks like I made the right choice in which part to upgrade. Like Jon, I chose the teflon caps, and like the Korneff amps only needed two (2).

MikE

I've been thinking of bi-amping my Altec 604's but the advice I keep getting scares me off. The main problem I'm told, is the high cross-over frequency (1500hz) and your 650hz is up there as well. The common thread of the advice I get,

-It has to be a damn good active cross-over or you'll kill the magic - definitely tubes - something like the Marchand. Big $$.

-With a cross-over point this high, the amps must be identical. I have an unused CJ MV-75 and my current amp is a Golden Tube Audio 300BSET. I hear "no way" on this combo and the chance of getting another GTA 300B with WE 300B's is nil. Since it must be SET's for me, this means 2 new SET amps. Big $$.

-Some think 300B SET on the bottom but 2A3 or 45 SET on top might work but this is an expensive experiment - I still need a tube cross-over before I can even start to play around with borrowed amps.

-The 604's are a bit forward in the 2-3k range and supposedly sound best with a notch filter. A few designs are out there to accomplish this passively but to do it actively it would probably be best to get a custom cross-over. Marchand can apparently do this but again, the price is going up.

I'm going to put off the active idea for now, build new cabinets for the 604's and try a Mastering Lab type passive cross-over incorporating a notch filter. I'm real interested to hear how your set-up works out as this may put to rest some of my concerns with active. I heard the JBL/Edgar salad bowl set-up at the Midwest Audiofest as part of his Titan system and was blown away - best reproduced music I have ever heard. His system was bi-amped but all horn loaded and passive from 100hz up. Have you talked to Bruce about your plans? He sure seems to have the magic touch with horns.

Billf

Billfort...actually I'll be going passive. I have talked with Bruce...what a nice and helpful man!

I have heard some of the same stories about actives that you have. I have also heard stories putting down passives. I am not a speaker designer or a cross-over designer...not even close...not even close to being close. Back to my point (if there is one) I guess I'll really just have to wait and see...I don't have enough listening time with active cross-overs to conclude anything for myself...sure...I've listened ta systems which have used active cross-overs...but I wasn't familar with that system either.

I guess we'll both have to wait and see.

as far as passives go...have you talked to Wayne at the Pi forum at all? He is actually supposed to be working on an active-cross-over kit too(I think)

I hear ya on the we300B thing. (What other tubes are you using?...get that system posted in the gallery (http://www.audiokarma.org/forums/forumdisplay.php?s=&forumid=31) forum here;) )

basically it all comes down to a big :dunno:

I did post to the Pi forum a while back about cross-overs for the Altecs as Wayne's compensation approach to bringing down the level of compression driver/horns to match cone drivers seems a natural to tame the forward midrange of the 604's. Never pursued this however as Wayne wanted full specs - including response measurements - for the 2 drivers that make up the 604 before he could come up with a cross-over design. I've never seen anywhere close to this for these drivers and have no way of measuring them. Most I've seen is the woofer parameters - enough to build a box but not much more.

I'll post my system details later today if I get a chance.

Billf

In my experience active crossovers increase dynamics and reduce distortion, these are good things. Personally I wouldn't get too doctrinaire about tubes in this situation, improvements are improvements. I've used SS prosound actives with tubes on the treble to good effect, so do other hornys I know.

Passive filters between preamp and amps also work nicely, right now I'm using them instead of an active and I'm very pleased.



www.chicagohornspeakerclub.org

Hey Tom...How are things?

I'm really not sure what I'll end up doing...and I do plan to try a few amps out (once I get the speakers done) and I will look at SS and tube both...I guess we'll wait and see.


I really have no experience with active cross-overs...hmmm...you know what...maybe I'll start a new thread in the DIY section asking about them.