The ST324 Tweeter in a Straight 8....wow!

kohked · 4047

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Offline kohked

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on: July 10, 2013, 01:48:51 PM
All,

I've been working from my "home office" lately (the living room) and sit just a few feet from one of my S8's.  The tweeter domes are mashed in a bit, and I was wondering how they actually *sound*.    So....I ran my Paraglow's to them directly and as expected, they sound like crap.   Some noodling around here in the Bottlehead galaxy has the FedEx man dropping off ST324 tweeters at the gate.   After looking at the two little boxes for a week, out comes the router and in go the new tweeters.

Understand that I didn't modify the existing (latest version) crossover at all; just wired in the new tweeters and surface mounted them.   Am I wrong to think these sound GREAT!?   Maybe I got used to the crappy old ones, but I'm hearing air and sound and nuance I haven't heard in a long time.  I play them non-stop just to confirm they sound so good.  I'm really happy I did this.

I suppose I'm wondering though....what's the acoustic result of these tweeters with the original crossover?   They seem *louder*, but overall I'm really happy and not inclined at the moment to build a new X-over.   Should I bother?


best,


Dennis


Offline debk

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Reply #1 on: July 10, 2013, 02:25:28 PM
Very cool

I have a pair to put into my Straight 8's.  One of the many projects I have.

Deb

Debra K

Eros 2Phono amp
BeePre2, Psvane ACME 300b
Kaiju, Linlai Elite  300b
Monamour 2a3 amps various tubes
Sota Sapphire, Pete Riggle Woody Tonearm, Kiseki Purpleheart Cartridge
Rega P6 Ania Pro cartridge
Roon Nucleus
MHDT Labs Orchid DAC
Jager speakers

Offline kohked

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Reply #2 on: July 10, 2013, 03:52:42 PM
Deb,

You really need a router to enlarge the existing hole...but after that it's only about an hour (tops) to do this job.


best,


Dennis


Offline Doc B.

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Reply #3 on: July 10, 2013, 08:42:55 PM
Yeah look at the relatively recent thread on this. The woofer crossover should stay the same. The tweeter crossover should be a single cap, but I do not recall the value. It's in the thread. The dome tweeter crossover is not optimal for the slot tweeter.

And yeah, it's way better than the old dome tweeter.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.

Offline debk

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Reply #4 on: July 10, 2013, 10:27:24 PM
Quote from: kohked on July 10, 2013, 03:52:42 PM
Deb,

You really need a router to enlarge the existing hole...but after that it's only about an hour (tops) to do this job.


best,


Dennis

Never used a router, it will be a good oppertunity to get one and learn how to use it!

Deb

Debra K

Eros 2Phono amp
BeePre2, Psvane ACME 300b
Kaiju, Linlai Elite  300b
Monamour 2a3 amps various tubes
Sota Sapphire, Pete Riggle Woody Tonearm, Kiseki Purpleheart Cartridge
Rega P6 Ania Pro cartridge
Roon Nucleus
MHDT Labs Orchid DAC
Jager speakers

Offline najo49

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Reply #5 on: July 15, 2013, 07:50:47 AM
The value of the cap is .6 i got that from Paul J.It somehow sets the level.

Jann Olsen, [email protected].  Lowther medallion 2 with pm2a./ extended foreplay lll,/EROS phono /Grado ref/ SOTA star Vacuum SME V, /  45 amp direct coupled,c4s,mQ nickel  / paramour  2a3 w MQ iron /Original SEX monos /Jena Cables /heathkit wm6a/ proAc Tablette 50 sig , with push pull

Offline Paul Joppa

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Reply #6 on: July 15, 2013, 09:35:39 AM
That value will get you in the ballpark, but it can be worthwhile trying other values nearby as well. Bigger cap - more treble.

Search the threads for much more detail, including the Climax design which was the best we ever did with that tweeter (also - of course - the many mechanical mods).

The tweeter has a peak around 3200Hz. It rolls off at 6dB/octave above there, and 8dB/octave below. By itself it's a fairly crappy tweeter! But a single-cap highpass at 20kHz changes that to flat 3200Hz-20kHz and -24dB/octave below 3200 - a classic 4th order Linkwitz-Riley response.

Paul Joppa

Offline Grainger49

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Reply #7 on: July 15, 2013, 11:00:37 AM
Rather than spend a fortune in capacitors buy some inexpensive metalized PP film caps.  Find the value then buy a nice one to match your findings.


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