Just got the new newsletter. WOW!!!!! Hold onto your hats, Bruce is on a roll. Changing the 300B OTL to DC and lowering the price and introducing a 300B push/pull [I figured this one was coming]. Way to go Bruce.
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I've always wanted to try a 300b amp. Most of the available were SET types with either really expensive output trannies, or inferior units that were still fairly expensive.

I'm going to be very interested in the P/P model. Hell, I'm going to design a speaker for it.

Let me echo sailor. Way to go Bruce.

steve
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Ray P
Will be interesting to see how DC filaments for the 300B SE-OTL are achieved, especially if there is a corresponding price decrease?

And I wonder if there will be LM317 or TL783 current sink devices?
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thegorn
Wow! People that think there is no where else to go in OTL technology, haven't met Bruce!
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Bruce Rozenblit
You see guys, I'm the anti-establishment amp company.  The old line establishment companies give you the same thing year after year, put a different box around it, and tell you its something new and improved. Then they boost the price because the new box is supposed to be better when its really just the same old thing.  Then the audio press chimes in and glorifies the new box because they get their money from the same companies that make the same old thing in the new box.  People have been swallowing that manure for decades and they are fed up.  They are tired of spending their hard earned money on things that never did work well and cost a fortune.  Then they come to me.        
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PetrL
If the new push-pull 300B will be sonically at least close to the present 300B OTL, then there is no more reason for transformer coupled  SE 300B to exist.
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Steve_S
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Boy, this web page is doing  crazy stuff for a while now. It looks like it's working in shuffle mode regarding posting times and replies. Does anyone else have these problems?

With  all this new and wonderful  development on the amp side we would only need somebody or some small company that would produce speaker cabinets for these 300B amps. I am thinking of the real stuff with Lowther (and maybe Fostex as cheaper alternative), no wasting of precious OTL power in  x-overs and low sensitive speakers anymore.

Backloaded folded horns as easy to build kits made out of Baltic Birch (no finish) but at reasonable prices (like  TS products!). Is anybody out there that has access to CNC routers? How many people would be interested  in such a project?

It's more or less a nightmare if you have to build it with a table- and mitersaw although it works.
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Wolfgang wrote:


With  all this new and wonderful  development on the amp side we would only need somebody or some small company that would produce speaker cabinets for these 300B amps. 



One of these small companies (one man company like Bruce's) is Ed's Hornshoppe. The Horned Heils should be a great match. I have them, but no 300B, but they will jam well with 1 or 1.5 Watts.
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Ray P
Capt. Z wrote:
One of these small companies (one man company like Bruce's) is Ed's Hornshoppe. The Horned Heils should be a great match. I have them, but no 300B, but they will jam well with 1 or 1.5 Watts.


Sorry but I'm going to stick my neck out. Whilst Ed's Hornshoppe speakers are, I'm sure, very nice products and to some extent will match the 300B OTLs they're not going to be the 'statement' speaker that the 300B OTLs deserve and that I think Wolfgang is talking about.

Wolfgang, I use a pair of Ketil Perow's AllFun BLH design using Lowther EX4 drive units. I built these myself but because of the nature of the complex woodwork, which is well beyond my carpentry skills, I invested my time in producing CAD drawings and had all the panels CNC routed. They slotted together perfectly just requiring most of my effort to go into finishing them. My day job involves working with CAD-type software and I would be happy to work on that aspect with you.

I've actually been considering another BLH project, my one regret about the AllFun build is that I shied away from building Perow's BigFun Horn and I've been thinking of remedying that. The BigFun is a little bigger than the AllFun but gets down to near 30Hz with the single Lowther unit. It uses a Tractrix profile rather than the exponential of the AllFun so the horn profile is actually of similar length. The EX4 units have excellent top end and don't need any tweeter support so crossovers are a non issue. Sound of the AllFun is amazingly detailed and dynamic and they really sing with the 300B OTLs. Of course, there are other premium drive units available that should be considered.

On the CNC routing aspect, shipping that amount of machined birch ply will be expensive so it may be better to produce CAD drawings that people can pass to a local CNC routing service, who will usually have access to suitable ply?

This guy has an interesting approach to achieving the horn profile;

http://www.diyaudio.com/forums/full-range/283795-pics-new-lowther-alfredo-horn-using-cncd-birch-ply.html

http://www.creationaudio.com.au/

Ray


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You must have read my mind, Ray!

The profiles glued together would float my boat. But I only would want to use Lowther and don't want to start again with calculations and adjusting the pressure chamber for a different speaker as I did with my Medallions for the DX4. The final measurement (near filed with calibrated test mike) looked perfect but I think it was more luck than anything else. They look very different (more linear without big dips and peaks) from what I saw in Stereophile reading the test about the Horn Shoppe horns with the Fostex.

I would get a pair of EX4 for my next project because to glue 3/4" felt inside the speaker was also not easy.

How did you find a company that does CNC routing for hobby speaker builders? I definitely would take your offer for helping me with the computer related stuff.


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ed schilling
Ray, you'd be shocked at the number of "statement" speakers my favorite speaker has replaced. Fancy drivers do not a statement make.

Look at it this way....I've been designing and building speakers for more than 40 years......I am not restricted to any brand or type driver. I can build any enclosure design you can dream up. So axe your self, why do I not use Lowthers? The reason is simple. I'm not swayed by all the BS claims and anecdotal comments about them and their cabinet designs. Overhyped, overpriced and mediocre performance. no thanks! A pair of Medallions (DX4? I can't remember the exact model but they were correct for the cabs)  once tried to stand in The Horns shadow. It was ugly and brutal for them. They sounded ok until we swapped them. They never got cut on again. Of 10 or 12 guys, no one cared to hear them a second time. For the whole weekend. They did look good standing next to the wall. The owner was not happy.

If I were building a speaker for the 300B it would be a backloaded corner horn  2 way with a series xover and a Heil driver. The Heil makes a Lowther sound broken BTW...............oh wait.............that system is  already being made and I've heard it! [smile]

I also must point out there are few iof any "BLH's" that actually are that. Not a single "BLH" that has a front exit is a proper horn...and I could care less who designed it (fostex, Lowther, etc)....period. The proper mouth on a 50Hz horn is almost as big as a door unless corner loaded and then it must be a rear exit. So it is not a proper horn with a front exit smaller than 1/2 a door in size. The term "BLH" is used fast and loose and seldom accurate.

For a Lowther in any cabinet to reach 30Hz it either must be making extreme excursion ( high distortion) at high outputs or it can not make high output. Those pesky laws and all..........

There is no way a Lowther that can play flat to 30hz can possibly play R&R at live volumes. A system  that can not play all types of music at live levels is simply severely compromised. Joni at a whisper or Metallica at 103db peaks should be easy for any system.

If people based their opinion of the quality of Bruce's amps based on cost or them being a kit he'd not sell a single one. They do not cost enough to possibly be any good and then you have to build it. See what I mean?
Ed

ps....I wish I had your CNC ability! I need a monocore made for my next form 1 silencer when I get the stamp [smile]



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ed schilling
Wolfgang, I just realized you had the DX4 in Medallions. Not sure how I missed that. I'm sorry for you. [smile]
Ed
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Don't be sorry for me, Ed...

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Ray P
ed schilling wrote:
Ray, you'd be shocked at the number of "statement" speakers my favorite speaker has replaced. Fancy drivers do not a statement make.

Look at it this way....I've been designing and building speakers for more than 40 years......I am not restricted to any brand or type driver. I can build any enclosure design you can dream up. So axe your self, why do I not use Lowthers? The reason is simple. I'm not swayed by all the BS claims and anecdotal comments about them and their cabinet designs. Overhyped, overpriced and mediocre performance. no thanks! A pair of Medallions (DX4? I can't remember the exact model but they were correct for the cabs)  once tried to stand in The Horns shadow. It was ugly and brutal for them. They sounded ok until we swapped them. They never got cut on again. Of 10 or 12 guys, no one cared to hear them a second time. For the whole weekend. They did look good standing next to the wall. The owner was not happy.

If I were building a speaker for the 300B it would be a backloaded corner horn  2 way with a series xover and a Heil driver. The Heil makes a Lowther sound broken BTW...............oh wait.............that system is  already being made and I've heard it! [smile]

I also must point out there are few iof any "BLH's" that actually are that. Not a single "BLH" that has a front exit is a proper horn...and I could care less who designed it (fostex, Lowther, etc)....period. The proper mouth on a 50Hz horn is almost as big as a door unless corner loaded and then it must be a rear exit. So it is not a proper horn with a front exit smaller than 1/2 a door in size. The term "BLH" is used fast and loose and seldom accurate.

For a Lowther in any cabinet to reach 30Hz it either must be making extreme excursion ( high distortion) at high outputs or it can not make high output. Those pesky laws and all..........

There is no way a Lowther that can play flat to 30hz can possibly play R&R at live volumes. A system  that can not play all types of music at live levels is simply severely compromised. Joni at a whisper or Metallica at 103db peaks should be easy for any system.

If people based their opinion of the quality of Bruce's amps based on cost or them being a kit he'd not sell a single one. They do not cost enough to possibly be any good and then you have to build it. See what I mean?
Ed

ps....I wish I had your CNC ability! I need a monocore made for my next form 1 silencer when I get the stamp [smile]





Ed, just get over it...
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