I fitted the ULN-RD78A low noise regulator to my BHL kit last weekend. At the same time I moved my lundahl SUTs from an external enclosure into the main preamp chassis. The two changes have removed mains hum (I speculate that this is due to the shorter connection from SUT to preamp) and a large amount of background hiss, which was not bad to begin with. My playback chain after the BHL phono preamp is passive TVC preamp > Bottlehead Stereomour 2A3 > Tannoy Little Red dual concentrics (about 94db sensitive, from memory). With no music playing I don't hear hum or hiss from my listening position approx 2.5m from the speakers.
excellent, very good choice.
but a component that ULN i think is too expensive for a project like this.
imho logically.
I'm not a technician, just a fan but I think that the problem is inherent to the project.
Based on personal experience and reports by others, low noise level is one of the strengths of the Boozehound Labs JFET phono preamp kit. Before adding the ultra low noise regulator I was using a cheap 24VDC power supply and MC7818 and noise levels were already lower than my Clearaudio phono stage. If you experienced high noise levels I think this must have been due to your implementation or system, rather than an inherent issue with the BHL kit.
Normally, in small applications such as the pacific, use this power supply:
Semplici regolatori di tensione Parte 4: Il rumore - [Italiano]
there is in english too.
however, in this case, the problem lies elsewhere: it seems to me that the drawing is wrong.
Semplici regolatori di tensione Parte 4: Il rumore - [Italiano]
there is in english too.
however, in this case, the problem lies elsewhere: it seems to me that the drawing is wrong.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.