xdanx Posted January 14, 2019 Share Posted January 14, 2019 A vrea sa ma apuc de un amplificator SE clasa A cu 2 buc 300B finale pentru o putere mai mare. Rugaminte : daca are cineva o schema buna spre foarte buna cu 300B. Vreau neaparat sa fie 300B si sa fie 2 buc pe canal. Dupa o simpla cautare pe google am gasit schema de mai jos. Cum vi se pare aceasta schema?????? Quote Link to post Share on other sites
gg101 Posted January 14, 2019 Share Posted January 14, 2019 (edited) Cu un singur 300B vei putea obtine lejer 10 Watt ,suficienti ca sa-ti pui toti vecini in cap. Cu doua in paralel / canal , lucrurile se complica un pic . Edited January 14, 2019 by gg101 Quote Link to post Share on other sites
xdanx Posted January 14, 2019 Author Share Posted January 14, 2019 La 10w THD-ul va fi mare, dar daca scoate 18-20 w la 10 w va fi mai mic. Si am boxe cu SPL la 90db trebuie un pic putere sa la miste. Quote Link to post Share on other sites
GU50LOVER Posted January 15, 2019 Share Posted January 15, 2019 La 14.01.2019 la 12:55, gg101 a spus: Cu un singur 300B vei putea obtine lejer 10 Watt ,suficienti ca sa-ti pui toti vecini in cap. Cu doua in paralel / canal , lucrurile se complica un pic . Te rogsă ne explici cum se complică? Si eu sunt pasionat de 300B... Quote Link to post Share on other sites
Borin Dodea Posted January 15, 2019 Share Posted January 15, 2019 (edited) Tuburile nu sunt identice deci in final va apare o "sumare" a doua semnale. Daca luam negativare fixa avem asa: pentru acelasi curent idle avem tensiunea din grila diferita si excursia de semnal permisa (nu avem driver potent pentru a intra in clasa A2) la intrare la un tub va fi mai mica decat la celalalt tub (sa zicem -25V fata de -30V). Daca luam negativare automata pentru acelasi curent idle vom fi nevoiti sa avem rezistente inegale in catod deci in grila nu vom putea aplica acelasi semnal de o amplitudine U pentru ca unul din tuburi va intra in clasa A2 (asta daca driver-ul este potent). De aceea nu se agreaza ideea folosirii de tuburi in paralel. Edited January 15, 2019 by adrian_pic Quote Link to post Share on other sites
George Posted January 16, 2019 Share Posted January 16, 2019 (edited) On 1/14/2019 at 1:49 PM, xdanx said: La 10w THD-ul va fi mare, dar daca scoate 18-20 w la 10 w va fi mai mic. Si am boxe cu SPL la 90db trebuie un pic putere sa la miste. Amplificator push pull (PP) cu 300B poate fi luat in seama? Edited January 16, 2019 by George Quote Link to post Share on other sites
OLIMPIU Posted January 16, 2019 Share Posted January 16, 2019 (edited) Investiti in 300B-XLS de la EML si veti obtine cu un singur tub puterile din tabelul de mai jos: ...asa cum spune si in tabel,vom gasi o infinitate se PSF-uri care sa ne satisfaca din punct de vedere armonic... http://www.emissionlabs.com/datasheets/EML300B-XLS.htm Edited January 16, 2019 by LMOlimpiu Quote Link to post Share on other sites
Borin Dodea Posted January 16, 2019 Share Posted January 16, 2019 (edited) 2 hours ago, George said: Amplificator push pull (PP) cu 300B poate fi luat in seama? Strici orzul pe gaste 300B are o mare particularitate: este cel mai liniar tub. Si cu un tub liniar faci musai un SE. La PP poti folosi tuburi neliniare bine merci dar la SE cu cat tubul este mai liniar cu atat obtii ceva state of the art. 300B a fost creat anume pentru audio. Vrei putere mai mare => solutia indicata de LMOlimpiu : 300B-XLS Edited January 16, 2019 by adrian_pic Quote Link to post Share on other sites
xdanx Posted January 16, 2019 Author Share Posted January 16, 2019 am gasit urmatoarea schema cu 300B XLS MERKUR is a Stereo Amplifier, with 2x14 Watt 300B-XLS Single-Ended Amplifier, by Dipl. Ing. J. Leven from Germany. This design is made around the Emission Labs 300B-XLS tube. As driver stage, the powerful tube is used in DC coupled configuration. This is a circuit diagram of an SE amplifier, designed for an EML 300B XLS tube. The driver stage consists of a DC coupled 6H30 tube, the output tube is the 300BXLS, that is a larger, stronger version of the 300B triode.The larger design is compared with a 300B, allows continuous operation with a higher Anode Dissipation (AVL). In the MERKUR-V1 circuit, this tube is operated with appr. 47 watts AVL. The use of a normal 300B is not possible in this circuit. The operating point of the 300B-XLS is to provide a simple, auto bias and negative bias allows a precise and permanent working point. This nice design is made by Dipl. Ing. J. Leven from Germany. The 300B-XLS amplifier was tested with various loudspeakers, and supplies enough power for a loudspeaker of 86dB or more. There is only one capacitor in the signal path and together with the Amorph Core 300B-XLS Transformer by Lundahl, it can be said that alls components match together excellent, and a detailed and well balanced sound picture occurs. The bias current of the 300B-XLS tubes can be adjusted easily and precise, because the bias scheme is a mix of Auto Bias and Adjustable Bias. This allows a stabile Bias from the beginning, which will remain stabile for a long time, before it needs re-adjustment. In the Circuit diagram, the connection schemes of the 300B-XLS Output transformer are given both for 4 Ohms and 8 Ohms. Quote Link to post Share on other sites
xdanx Posted January 16, 2019 Author Share Posted January 16, 2019 si versiunea de 20 w http://4tubes.com/SCHEMATICS/LUNDAHL-TRANSFORMERS/!LEVEN-Germany/300B-XLS/LE-300B-XLS-SE-2011_Gesamt.pdf Dar cand am vazut cat costa 2 tuburi 300B XLS mi-a cazut mousul din mana Quote Link to post Share on other sites
Borin Dodea Posted January 16, 2019 Share Posted January 16, 2019 Crezi ca 6H30P este ieftin? https://www.thetubestore.com/russian-6h30p-dr Quote Link to post Share on other sites
viobio Posted January 16, 2019 Share Posted January 16, 2019 Cine își dorește un amplificator SE cu 300B..... nu trebuie să aibe un buget anume. La vară vreau să îmi fac un PP cu 300B, o să fie fără buget, îmi doresc de ani buni un PP cu 300B, din păcate nu am avut timpul necesar pentru a-mi face acest amp, l-am amânat ani de zile. 300B merită tot ce este mai bun, din ce am citit, în lumea extremiștilor, audio,,numiți audiofili, este considerată lampa supremă. Quote Link to post Share on other sites
xdanx Posted January 16, 2019 Author Share Posted January 16, 2019 Suprema, suprema dar un 300B XLS este 900$ bucata. Totusi... 300B normal de la Genalex este 145 euro parca mai merge. Dar ce sa fac. Cu doua lampi normale este riscant sau greu de echilibrat, iar cu una este prea scump, asta ca sa ajung la 20 w. Exclus sa fac un ampliu de 8 w Quote Link to post Share on other sites
Kosmin Posted January 16, 2019 Share Posted January 16, 2019 Pentru 20W de ce nu 845 / GM70 polarizat mai la ralanti ? ... (in config. parafeed ca sa fie "smart_budget" ). Quote Link to post Share on other sites
maresaldeflota Posted January 16, 2019 Share Posted January 16, 2019 Acum 24 minute, xdanx a spus: Suprema, suprema dar un 300B XLS este 900$ bucata. Totusi... 300B normal de la Genalex este 145 euro parca mai merge. Dar ce sa fac. Cu doua lampi normale este riscant sau greu de echilibrat, iar cu una este prea scump, asta ca sa ajung la 20 w. Exclus sa fac un ampliu de 8 w https://www.rototubes.com/300B-EH.html Quote Link to post Share on other sites
