Monitor 4, About 6HB5 Tubes

Read more on the Acoustat Monitor 4 in our home audio section

Massimo2005-08-16 19:51

Hello, I have a pair of Monitor 4 and for a problem with 6HB5 tubes(wear) I need to change them.In your opinion and experience which brand is to prefer in term of sound and musically. Sincerely Massimo


Massimiliano Conte2005-09-02 13:18

Hi Massimo, after long time on my Acoustats X, now implemented in a pair of Monitor 4 type, I can say that the best tubes, in my experience, are Sylvania and G&E, in particular on time reliability. National ones are banished from my tube stocks. About sound and musicality parameter, what you can also mount on 6HB5 are Herbie\'s Audio Lab rings: this test is very interesting. Ciao Massimiliano

Massimo2005-09-15 21:30

Caro Massimiliano, ti ringrazio per la risposta datami sulle 6HB5:condivido il tuo parere e presto sostituirò le vecchie valvole(due delle quali ahimè bruciate) con un ottetto di Sylvania. Inutile dire che fa piacere sapere che anche tu sei completamente soddisfatto delle tue Monitor 4 per le loro assolute qualità in termini di musicalità.Hai mai avuto problemi tecnici con gli OTL?Se sì ti avvali di un riparatore in particolare e per le parti da sostituire attingi da qualche riserva affidabile? Cosa mi dici degli anelli antivibrazione di Herbie\'s ,intendo dire quale modello è da preferire e mi consigli? Ti ringrazio e saluto. Il mio email è

Mario2010-11-20 20:39

buy n° 8 type 6hb5

Luciano Veneziano2017-02-08 11:11

Salve a tutti. Ho ereditato una coppia di monitor 4 che credo non funzionino bene. Mi servirebbe qualche indicazione su quali possano essere i punti deboli. Credo che siano le unita OTL a non andare.
Vorrei parlare con Voi per riuscire a farle funzionare.

Grazie a tutti.

Bill Cross2017-11-29 01:39

I am interested in driving a speaker with an RC coupled plate of a 6146B with a back chamber a foot deep going below 1 kHz for the electrostatic element. I want to roll off the lows between 1 kHz and 500 Hz and use more gain for the 4 dynamic speakers at 500 Hz from the microphones behind the electrostatic diaphragm with one microphone for 2 speakers, one on each side of the electrostatic diaphram which is 3 inches wide. The 4 speakers have 15 W each and go down to 80 hz. there is a hybrid switching/non switching amplifier with 143 kHz carrier and a 6100 Hz lowpass with a trap for the fundmantal and another 12000 Hz lowpass and at no output the ripple is 3 u V p-p and then a transformer and two speakers in series and the current sense resistor for the transconductance amplifier for reduced magnetic distortion from the voice coils. The transformers have 15 times as many turns in the primaries as the secondary and the 2 complementary symmetry common emitter stages drive the primaries with plus and minus 22.5 V power. The bias current is 60 mA. The power supply for the 6146B is 5000 V with 25 mA at full power setting. There is also half, quarter and eighth power to save on your electric bill. The 2 speakers are supported by a subwoofer with possibly spring compensation for the speaker and air stiffness.

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