TAD replacement diaphragms

[Rocky]

I know TADs compression drivers, with their beryllium diaphragms are concidered some of the very best compression drivers available.. But how does they perform with Radians replacement diaphragms in aluminium? Opinions?

 

[Tim Moorman]

Radian Diaphrgms

Rocky,
From what I gather, they do a good job, at perhaps 90% of the performance of the beryillium originals.

I have the 2001 1", and when compared to the Radian 1" driver, the response in only slightly more rough, with an additional dip up around 8K as I recall, on the same horn.

Tim

 

[Rocky]

Great. Thaks Tim.
I will not use them all the way up to 8k. They will be crossed at 5k, although 1st order. Would you say TAD 4001 in good condition but no diaphragms, are worth a price of $150 each?

 

[Tim Moorman]

TAD

Rocky,
Heck of a good deal at $150. They easily have that much machining in them. Built like a cannon ball.

Tim

 

[Rocky]

Thank you very much Tim.

 

[roddyama]

Rocky,

I have replaced my failed 4001 diaphragms with Radians. I use them from 1200Hz up to ~12kHz where a pair of 077's takes over. I like them better than the TAD's. I will post more details later as I'm at work now.

 

[Rocky]

This keeps getting better

I am looking forward to hear your story, Roddyama.

 

[Tim Moorman]

TAD

Rocky,

Get all you can at that price, because you won't find them any cheaper.

Rodd,
What horns are using for the TADs?
What about the midbass?
Where in Michigan? I'm in Fort Wayne.

Tim

 

[Rocky]

I just posted my order

Radian diaphragms will be somwhere around $250 each from what I saw earlier tonight.. Anyone cheaper?

 

[roddyama]

Re: TAD

This keeps getting better

I am looking forward to hear your story, Roddyama.

The TAD diaphragms are detailed and have good extension (depending on the horn you use). They are very musical, but they have 2 major short-comings, one, they are a bit too laid-back for my taste and two, they are too fragile. The surround and dome are all one piece of beryllium so if you over power them or hit them with a little DC, pop, they're gone. The radians are far more robust and will take nearly double the power. Here's an email I sent to a friend.

As you said, the Radians seemed to have broken in and are really sounding good. It took a couple of weeks but I like them better then the TAD diaphragms. They are definitely more “alive” and dynamic. I don’t get any sense of compression and they blend very well with the JBL LE10A’s.

Radian shows a full range peak in the response of about 12db centered at about 1kHz. Since I run them from 1200Hz up, I put a single cap in line that roll off from 5kHz. This seems to work well in flattening out the response. Flutes, horns and violins all seem smooth and balanced without the single note blaring out at you. (find the plot at the end of this pdf http://www.radianaudio.com/products/pdf/high_res/1292.pdf )

Recently I began to use a friends mini-Aleph while I build my own. I never had the chance to hear the Aleph on horns. I have to say that I’m hooked. All the benefits of my old Mac tubes without the neuroses of worrying that my tubes are going bad. I never knew detailed could be so smooth and musical.

Rodd,
What horns are using for the TADs?
What about the midbass?
Where in Michigan? I'm in Fort Wayne.

Tim

Here's a link to pic and a description of my system before the TAD's diaphragm replacement.
http://www.diyaudio.com/forums/showthread.php?postid=305209#post305209
I'm just north of Detroit in Warren.

I just posted my order

Radian diaphragms will be somwhere around $250 each from what I saw earlier tonight.. Anyone cheaper?

I think my total bill from Radian was $312USD for the 2 - diaphragms + shipping.

 

[Rocky]

Order confirmation recieved Finally I got a good deal on mid+ compression drivers for my system. I have been scanning Ebay for a good while, but those japanese vintage freaks always snapped my JBL 375 or WE drivers don't they ever run out of money in Japan..

Now.. I checked the datasheet on the Radian diaphragm... Since I will power the system by 1.5W SET (I'm using 300B SET monos with 9W at the moment, but they need to go, and I am in the process of building a lower-watt replacement) , I will avoid the cap filter method for response flattening, and do this actively. I have an active DIY 2-way 24dB/oct LR XO currently splitting at 500Hz wich will be moved to 600Hz (on breadboard still, but it works fine... OPA2134s) so I think I will fix the response by equalization in the high pass (tweeter and mid will be crossed passively 1st order, using the same amp). With XO at 600Hz, i figure I'll make the TADs a 425Hz tractrix horn.. some 12,9cm radius... No reason why the TAD 4001s wouldn't perform good in round tractrix?

 

[roddyama]

...I will avoid the cap filter method for response flattening, and do this actively.

Just a warning. The primary reason for the series cap is to keep low frequency amp output anomalies from the driver in my tri-amp setup.

No reason why the TAD 4001s wouldn't perform good in round tractrix?

None that I can think of.

 

[Tim Moorman]

TADs

Rocky
Sounds like you are all set. The Radians seem a little high, but not way out of line. Good luck with the system.

Rodd,
Interesting set up. I have 80 Hz Edgar horns under either Community M200s or JBL 2440 mids. TAD 2001 or Altec 902 above.
I also built a bass horn for the bottom end to about 28 Hz.
Takes up a lot of room, but has some snap.

Am considering changing to 40 Hz horns(2226 woofs) to about 250 Hz, then mids (JBL 2123 10") to 1200 Hz as you have done, then mids/highs. Bass horn below about 55 Hz.

I have the drivers, just need to get going on the construction.

Tim

 

[Rocky]

Just a warning. The primary reason for the series cap is to keep low frequency amp output anomalies from the driver in my tri-amp setup.

Thanks for the warning. I didn't think of that.. I'm just so notoriously afraid of passive crossover components in combination with SET.. Maybe I'll use a passive cap for this purpose.. but I guess I'll place it further down.. such as 600Hz providing another order to the already 24dB/oct slope, and still use active equalization to get correct response??

 

[Rocky]

Re: TADs

Rocky
Sounds like you are all set. The Radians seem a little high, but not way out of line. Good luck with the system.

Thank you Tim. Good luck on yours

 

[roddyama]

Re: TADs

Rodd,
Interesting set up. I have 80 Hz Edgar horns under either Community M200s or JBL 2440 mids. TAD 2001 or Altec 902 above.
I also built a bass horn for the bottom end to about 28 Hz.
Takes up a lot of room, but has some snap.

Put some pic in the Systems Pictures & Descriptions thread.

Am considering changing to 40 Hz horns(2226 woofs) to about 250 Hz, then mids (JBL 2123 10") to 1200 Hz as you have done, then mids/highs. Bass horn below about 55 Hz.

I would like to make a nice compact mid-bass horn to work down to about 70Hz or so. I bet I could build something about the same size as my LE10A boxes + stands. Them snares would really smoke than.

 

[roddyama]

Thanks for the warning. I didn't think of that.. I'm just so notoriously afraid of passive crossover components in combination with SET.. Maybe I'll use a passive cap for this purpose.. but I guess I'll place it further down.. such as 600Hz providing another order to the already 24dB/oct slope, and still use active equalization to get correct response??

If its any consolation, I use an active 12db/oct hi-pass at 1200Hz but use the natural roll off for the top-end x-over to the 077. The 077 has a coil (Alpha) in series and a cap in parallel, and oh yes, I use an L-pad on it as well. The point is that the one series cap is the only component attached to the 4001's.

 

[Rocky]

If its any consolation, I use an active 12db/oct hi-pass at 1200Hz but use the natural roll off for the top-end x-over to the 077. The 077 has a coil (Alpha) in series and a cap in parallel, and oh yes, I use an L-pad on it as well. The point is that the one series cap is the only component attached to the 4001's.

Sounds like a very smart setup indeed, but when I aim at using the 4001 down to 600Hz that is yet another octave and another -6dB from the response cap.. solves one problem, but creates another by a dip in the midrange 600Hz-1200Hz.. It is only usable in a setup like yours, crossing at around 1200Hz.

 

[roddyama]

Sounds like a very smart setup indeed, but when I aim at using the 4001 down to 600Hz that is yet another octave and another -6dB from the response cap.. solves one problem, but creates another by a dip in the midrange 600Hz-1200Hz.. It is only usable in a setup like yours, crossing at around 1200Hz.

Actually, if you size the cap for about 5kHz, it's only down 18db at
625Hz, but the FR is still +12db there so you really only down 6db. Now this is considering a flat impedence curve, which we know it doesn't have. I haven't ploted the impedence curve for the radians, but I would suspect that it will be rising in the 600Hz region. This is going to lower the effect of the cap and therefore be less attenuated. The beauty of the strategy is that it only cost you the price of 2 - 4.7uf caps to try it. BTW, don't make your judgement until the diaphragms have broken in.

 

[Tim Moorman]

Midbass

If you can, try horn loading the midbass. You will see a big improvement in kick drum, percussion stuff. Makes the mids sound cleaner, too, if the crossover is right (phase aligned).

Tim