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Multi-Way Conventional loudspeakers with crossovers

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Old 6th October 2017, 09:13 PM   #11
Kay Pirinha is offline Kay Pirinha  Germany
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I've replaced those non-polarized 25µF electrolytics by myself, using a combination of 15µF + 4µ7 + 4µ7 foil capacitors each, 'cause I don't like any 'lytics in xover networks. I've done the same in the xovers in my lb 3522C speakers previously, with good sonic results.

Yes, mine are the lb 3521B version, probably somewhat newer than yours'.

I don't know if this epay speaker will fit, let alone that there's only one offered. You may want to find a 4 ohms 10" driver with a fres next to 20 Hz - a rather difficult task, I'm afraid.

Best regards!
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Last edited by Kay Pirinha; 6th October 2017 at 09:15 PM.
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Old 6th October 2017, 09:34 PM   #12
Kay Pirinha is offline Kay Pirinha  Germany
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I've found these two rather affordable speakers: Kenford and DYH. I don't know whether Pollin wants to ship to your country, but for that money I'd give one of them a try. In addition you need four clamps each for mounting them, of course.

Best regards!
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Old 6th October 2017, 09:56 PM   #13
Lojzek is offline Lojzek  Croatia
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Quote:
Originally Posted by Kay Pirinha View Post
You may want to find a 4 ohms 10" driver ...
Best regards!

It appears that original woofer unit was an 8 ohm since the XO frequency is cca. 700 Hz and the LP filter from the schematic is consistent with this conclusion.
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Old 6th October 2017, 11:58 PM   #14
muzyk_ant is offline muzyk_ant  Romania
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Kay, I found the SBX2530 in my country at quite a good price: SAL SBX 2530/BK Difuzor de medii-joase, 250mm, 8Ohm, kevlar
I guess it is about the same thing but in black kevlar. But then again 4 or 8 ohms ?

It seems that the original PCH 245 was indeed 8 ohm or they made it in 4 and 8 ohm versions ? : Heco Pch 245 >> Seite: 1 >> Beendete Produkte >>
Thanks for the guiding Lojzek.

At the end of the day I do not plan to make them as original as they where in 1971 an maybe a fresh new woofer would be a good surprise. I do not indend to change the filter config. dough, maybe changing those electorlitic caps.
will try to run a simulation with the sbx... hmm

Last edited by muzyk_ant; 7th October 2017 at 12:05 AM.
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Old 7th October 2017, 09:55 AM   #15
Kay Pirinha is offline Kay Pirinha  Germany
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As said before, the PCH 245 in my lb 3521B measured RDC = 3.2 ohms. So supposedly it's impedance is 4 ohms. WEGA, the manufacturer of the speakers, names their impedance at 4 to 8 ohms, though, and allows two pairs of speakers to be connected to their receivers and consoles, rated at 4 ohms minimum.

Best regards!
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Old 7th October 2017, 01:30 PM   #16
Boden is offline Boden  Netherlands
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Hello Muzy_kant,

None of the woofers suggested come close to the original German woofers from the early seventies: extremely compliant/low fs, classic acoustic suspension woofers, typically with fs around 25-26 hz for a 20 cm woofer and around 22-23 Hz for a 25 cm woofer. Sort of Geman variety on the AR theme, but then with Dr. Kurt Müller rubber surrounds and occasionally (e.g. Braun) cast frames.

If you can trace one or two of the Hungarian Videoton/Hangszoro HA1038 25 cm woofers you come very close spec. wise.

Good Luck,
Eelco
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Old 7th October 2017, 02:35 PM   #17
muzyk_ant is offline muzyk_ant  Romania
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Hi Eelco, never heard of HA1038 ,Videoton dough I'm from the area..
22Hz fs is extremely low ... found some new speakers that can do that but they are way over the budget for this restoration
What about some Heco's from the Superior 600 speakers ?
Tieftoner HECO SUPERIOR 600 | eBay
Found a couple in my country at a resonable price and condition.
Anyone know some Thiele Small for those woofers ?
Thank you !
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Old 8th October 2017, 09:29 AM   #18
muzyk_ant is offline muzyk_ant  Romania
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Eelco, if you mean this woofer: Hangszoro VT HA25/1038(451) 8R110W | Elektronika
that is pretty cheap, do you think it will do the job ?
found also this:
VIDEOTON 25 cm-es MELYSUGARZO PAR nagymagneses - Vatera.hu
VIDEOTON HA25/10KS 4Ω - Vatera.hu
HA25-450 Melykozephangszoro - Hangszoroshop - Minden ami hangszoro
VT - HA25-503

Regards

Last edited by muzyk_ant; 8th October 2017 at 09:41 AM.
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Old 8th October 2017, 12:34 PM   #19
Kay Pirinha is offline Kay Pirinha  Germany
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Be careful with these! Due to their lack of a suitable gasket, at least the 1st, 2nd, 4th and 5th one appear to be dedicated for front mounting solely. You need a rear mount driver. For the 3rd one it's hadly to tell from the picture.

Best regards!
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Old 8th October 2017, 12:43 PM   #20
Boden is offline Boden  Netherlands
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Looks like it, but seems to have a much smaller magnet than the 12 cm dia magnet assembly mine have. Bought them in Hungary some 15 years ago for a few Forint. Replaced the foam surrounds with rubber surrounds.

In case you want rear mount simply make a 4 or 6 mm MDF ring between surround and frame as a sort of hard gasket.

Eelco
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