Sonab OA-4 (mkII) & Visatron TW 70 tweeters?

[iub]

Hello

I've recently been gifted with two Sonab OA-4 (mkII). While the speakers were quite dirty, the general state was pretty decent, and there does not seem to be any damage due to moist or similar. However the Tweeters look to be in rather bad shape, with some rusted areas.

I am aware that the Obi t22oa are the "standard" replacement tweeters, since the Peerless C62 has been discontinued. Sadly, though, the t22oa's are rather expensive, especially since they would have to be shipped to germany. Thus, I was wondering whether someone has any experience fitting similar speakers with the Visatron TW 70 (http://www.visaton.de/en/chassis_zubeho ... w70_8.html)?

These would be significantly cheaper and easier to acquire, and while they are slightly differently shaped than the MT20HFC's I am sure they could be made to fit.

Any advice and/or experience with similar equipment would be more than welcome!:)

[Villee]

Hello!

Rust doesn´t affect to the sound if the tweeter´s membrane or/and voice coil are not damaged. Before thinking about changing the tweeters check the original tweeters and measure their dc-resistance (should be for a 8 ohms tweeter about 8 ohms +/- 10% and for a 16 ohms tweeter 16 ohms +/- 10%). OA-4 has two eight ohms and one sixteen ohm tweeters per box.

If the original MT20 tweeters measure okay and functions you are not going to gain anything if you change to Visaton. MT20 in good shape sounds better/fits better to the loudspeaker design than TW-70.
I have a pair OA-4 type II original from my grandfather (bought new in 1973) and they still sounds fine with original tweeter units. However, if your MT20HFC´s sound bad, you can also try to coat the tweeter cone by using some diluted (?) glue which remains flexible. If your MT20´s are dead, then you have to consider to buy 1. T22OA (recommended is to do some filtermodification, instructions can be found on carlssonplanet) 2.used MT20HFC 3. something else with fitting specs
More accurate information regarding on OA-4 renovation, check "how to renovate" from carlssonplanet main site.

BTW.I think that OA-4 is a nice speaker and looks beautiful, although it´s crossover point is a bit too high, at 3500 hz, which is too high to tame the Philips 9710´s peak somewhere at 3000hz and it does not go as low as OA-5 or especially my OA-6 type 2A

[iub]

Thank you for your answer! You are probably right, I will check the resistance and do an actual listening test before I buy anything, I actually haven't had a proper chance to do that yet. Last night I did stumble upon another alternative: http://www.hoejttalerbutikken.dk/produc ... roduct=515

The guy in the .pdf used them as replacements in an OA-14 and seems to be pretty happy about them.

Thank you for the tip with the diluted glue, might be useful!

Regarding the 9710s, I've actually considered replacing them with some Visaton BG20s, since I have a pair lying around. The 9710 are in decent condition, but the general agreement seems to be that they haven't exactly aged well, so I thought it might be worth a try.

[C-man]

the BG20 is a good and cheep replacmant,i juse them in my popboxes,BUT i still prefer to run my Oa5 whit 9710 on my tube-amp they sound litel more "alive" then the BG20 that i run on a solidstate amp(Proton) but when i use the 2paiers love is in my ears!
But now i need to listen to my 48 new Cds from today!

[Villee]

I should only replace the Philips 9710 with Visaton BG 20 (I´m planning to do this) as a woofer in OA-6 type 2, because it´s larger cone excursion and therefore superior bass-handling (am I wrong?). BG20 is also easier load to the bass-energizer (which drives the 9710 as bass placed downwards, midrange 9710 + 4 MT20s is driven directly from your receiver/amplifier etc) and the risk of killing the energizer with higher volume is reduced (energizer is a bit hard to repair, but it´s possible, I can prove that).
Although I haven´t listened the BG20 so I don´t know how it´s going to perform ass a bass-mid in OA-4. 9710 has it´s own unique sound and therefore using Visaton BG-20 can destroy the typical sound of OA-4, OA-5,OA-6 and V-1.
Recommended replacement for the 9710 is Obi F87 (Hifi-kit 1495 kr/about 150 euros) which i would buy immediately, if the price would a bit lower
Sorry my negativity for using BG20, but I´m a fan of 9710M (have listened OA-4 since I was two...).

[Villee]

You bought 48 new cd´s at one day? whoh:D I buy about a few LPs per month (don´t like cd-format) and "download" cds and lps from library to computer and cassette tapes!
As you see I like vintage stuff

[Martin Dellstig]

Hi

Just a minor comment to avoid misunderstandings.

The glue for the tweeters is not to be used on the whole cone, only in the groove around the cone.

In my ears the 9710 is better than the BG20, the "problem" is a problem mostly on axis.
I don't usually listen to the music standing over the speaker.

The BG20 has it's points but some minuses also.
The sensitivity is a bit low in he low-frequency region, it starts dropping from, if my memory serves me right, approximately 200 Hz.
This disturbs me.

Best regards

Martin

[Villee]

"The glue for the tweeters is not to be used on the whole cone, only in the groove around the cone."

forgot to mention that

[C-man]

You bought 48 new cd´s at one day? whoh:D I buy about a few LPs per month (don´t like cd-format) and "download" cds and lps from library to computer and cassette tapes!
As you see I like vintage stuff

Well i dident buy them,i did get them at work from a customer that did a clear-out on his workspace!(A lot of goodies i can say to!)
Sorry fore the OT!

[jansch]

I agree with Willee and Martin - Do not replace 9710 with Visaton BG20 in OA4, OA5 or in OA6type2 for MIDRANGE.

BG20 is perfect as BASSPEAKER in OA6type2 and there is no need for any trimming.

It is hard to find a fullrange speaker with equal or better midrange than the 9710 in a Carlsson if the X-position is correct. I have tested different Fostex, F87, Visaton, Monacor, JBL.

It,s rather easy to fix the X-position..... if it's not to bad (max 1mm out of spec)