Tweeter instelling 22ah587

Alles over onze geliefde MFB boxen in deze categorie.

Moderator: Moderators

Plaats reactie
Bernard83
Berichten: 4
Lid geworden op: 16 jan 2023, 16:14

16 jan 2023, 22:58

Hello. I'm a fan of mfb. I have a pair of 541 I repaired and renovated a pair of 532 with the thomas kit. I am pleased to have purchased a pair of mfb 587. The previous owner changed all capacitors. So I set the quiescent currents and the 3 levels.
After listening there was too much treble. For a comfortable listening I am obliged to adjust the treble of the preamp 551 a -2 -3
Before setting the treble I had a signal of 1.8vpp (+18db) instead of 2.14vpp (+19.8db)
I don't understand why after adjusting the levels correctly, listening is uncomfortable.
So I checked that my entry level was 0.22vpp. Everything is ok. I may open the speaker to check the reference of the tweeters (ad0163/T15)... Yet everything seems to bé conform externally.
Thanks you to give me your opinion

Bernard
Gebruikersavatar
Remi
Donateur
Berichten: 11774
Lid geworden op: 16 jun 2005, 21:04
Locatie: Didam

24 jan 2023, 23:01

the levels seem ok, correct frequency?
"Hoezo nu wel genoeg? D'r is toch nog plek!" jaja, waar dan? "Ha! d'r kan nog wat in de auto!"
Bernard83
Berichten: 4
Lid geworden op: 16 jan 2023, 16:14

28 jan 2023, 18:21

Hi
I just opened the box again and the tweeter is an AD21160 T8... Not T15.
I understand better that the factory setting is too high... Which setting to use now with a 8 ohm tweeter ?
Thank you for your help
Gebruikersavatar
Remi
Donateur
Berichten: 11774
Lid geworden op: 16 jun 2005, 21:04
Locatie: Didam

28 jan 2023, 18:34

can't say, it should be a T15. only thing to do now is adjust by ear i guess. and try to find a T15
"Hoezo nu wel genoeg? D'r is toch nog plek!" jaja, waar dan? "Ha! d'r kan nog wat in de auto!"
Bernard83
Berichten: 4
Lid geworden op: 16 jan 2023, 16:14

28 jan 2023, 19:19

Waiting to find an AD0163/T15, I will try to reason about the power for the setting.
On 15 ohms 2.14 Vpp gives 0.572w.
To have an equivalent power under 8 ohms I have to set the output level to 1.56v.
I'll do it like that and I'll tell you.
I could also add a 7 ohm resistor in series with the tweeter...
If anyone has another idea, I read it with interest. Thank you
Gebruikersavatar
Thomas
Site Admin
Berichten: 12099
Lid geworden op: 16 jun 2005, 15:55
Locatie: Lochem, Gelderland
Contacteer:

28 jan 2023, 20:20

Ad21160is the midrange. Please check the tweeter magnet for correct information. Is the midrange working correctly?
Thomas Baur
webmaster http://www.mfbfreaks.com
De Enige Echte Philips Motional Feedback Website!
Bernard83
Berichten: 4
Lid geworden op: 16 jan 2023, 16:14

28 jan 2023, 20:42

Both boxes are equipped with the same tweeter: AD2160 ST8.
I resumed the settings according to my logic of powers (1.57Vpp) and the laws of physics seem to be true.... I get clean, non-aggressive highs.
The medium bass and treble ensemble seems well balanced to my ear. I attach the photo of the tweeter caregivers.
I don't understand why there is this reference to tweeter.
Do I have anything to gain from changing them ?
Bijlagen
IMG_20230128_182838.jpg
Plaats reactie