In the late 70s, the bass-midrange speakers VKN-1231 (index OH 0469274-82) were very popular for their fast elastic bass and rich timbre in the middle. In the periodical literature of those years, there were many developments based on these speakers, up to Hi-End. But few people knew that there was a broadband version of them (index OH 0969274-78), which was released in a limited series and which is just offered for sale.
The history of the creation of this series of VKN is interesting. In the mid-70s, a group of enthusiasts at the Voroshilov plant in Blagoevgrad, taking Japanese DS (Diatone) speakers as an example, developed their line of speakers, which were supplied both to the domestic market and for export (France, Sweden) … They had a heavy cast frame, a large Alnico magnet, a multi-wave suspension made of fine fabric with impregnation, and a lightweight dense diffuser. All in total provided a band of 25-4500 Hz without dips in the frequency response, sensitivity of about 95 dB, power of 40 W, Qts of about 0.3, weight 3.5 kg. After the 80s, the magnet was changed to ferrite, after the 90s, Chinese components were used, and clones of speakers based on the first models were no longer as interesting as all modern “Chinese meat”.
Difuzorul bulgăresc de 30cm, modelul BKH1221 (VKN1221 – mai multe despre denumire), căruia i-am măsurat acum 4 ani parametrii, între timp a suferit o uşoară degradare. Mai exact adezivul folosit la lipirea spider-ului pe coşul difuzorului s-a a devenit complet uscat, cauzând dezlipirea.
Am profitat de ocazie pentru a studia cum arată bobina. Am demontat şi capacul magnetului.
Coşul difuzorului este din aluminiu, la fel şi capacul magnetului, care se fixeaza printr-un şurub central. Eticheta cu modelul şi specificaţiile este tot din aluminiu inscripţionat cu vopsea şi este fixată de acelaşi surub.
Şi dacă tot l-am reparat, am zis să reproiectez şi câteva tipuri de incintă pentru el.