donsachs
Responses from donsachs
| 300b lovers This has been an interesting thread. I didn't start it, nor did I expect it to have this long a life. It is very clear that there are many ways to build amps and preamps. I just want to restate my goal for this project. I am semi-retired. I w... | |
| 300b lovers Yes, these amps sound very good after 10-15 minutes and are very consistent. They sound the same every day. I have the preamp and amps plugged into a Puritan supply, which does clean up grunge in the AC line. Basically, you turn them on and th... | |
| 300b lovers The Blackbird amps are running the 300b tubes at about 400V B+ (plate - cathode voltage), and just a wee bit under 80 mA. About 31.5 watts at idle. They sound wonderful and should last a very long time. The tubes each have their own independent re... | |
| 300b lovers @tuckia08 Thanks for your comments. I have heard a number of 300b now, but not the new WE 300b and I have not heard the European expensive tubes. When I tried the Linlai WE300b copy I stopped looking. I can get them for about $750 a quad from ... | |
| 300b lovers Typo above, choke loaded is clearly not RC coupled, but rather LC coupled, sorry. At any rate, full interstage transformer coupling was easily the best sounding. | |
| 300b lovers Which is why, on my highly resolving system, I could clearly hear the differences between CCS loaded RC coupled, choke loaded RC coupled, and interstage coupled versions of essentially the exact same amplifier. IT coupling won hands down in all a... | |
| 300b lovers I have explored all sorts of variants of this basic circuit for about two years now, and have learned what I like and understood why. This is a deceptively simple circuit, except that there is subtle complexity. Often, we get caught up in the ... | |
| 300b lovers No, the comparison isn't really fair. The little Chinese amp is a nice value for the money, but it is a single ended design made of, shall we say, "cost effective" parts. It probably makes 7 or 8 watts per channel. The mono 300b amps are built... | |
| 300b lovers The regulated filament supplies for each 300b can deliver 3 amps, and the tubes draw 1.2 amps, so they are coasting along, like the B+ supplies. As Lynn described, the amp is lightning fast. I would love to audition the Elrog 300b in it. I ha... | |
| 300b lovers Charles, I am not sure what Meyer would think of the Blackbird! There are some elements of it that are aligned with his thinking and others that are radically different. I would be interested to hear some amp of similar power that he has built ... | |
| 300b lovers Thomas Mayer builds seriously good amplifiers:) I have his octal phono circuit saved, and one day I will build myself another phono preamp with my power supply and his signal circuit. I bet it will sound very good. His tube blog is wonderful. | |
| 300b lovers @alexberger Spatial Audio Lab will be in charge of presentation at shows. I know we are returning to the Pacific Audio Fest in Seattle again next summer. Beyond that I don't know. We are focusing on getting the preamp and amps into production... | |
| 300b lovers I managed to update my ancient website with the beginnings of 300b project page. There is a photo of the final prototype of the Blackbird 300b monoblock amp at the bottom of this page. Spatial will change the look a bit, but dimensions and layou... | |
| 300b lovers Yes, we are pretty much back to an updated Karna circuit with more modern power supply topology, and custom wound iron everywhere. I listened to every possible variant of the circuit and it is obvious that removing all coupling caps and going wit... | |
| 300b lovers @atmasphere First off, this thread was started by a fellow who has a rough first prototype of a zero feedback push pull 300b amp, so of course we are discussing that. I agree that in that circuit you hear everything. I will tell you that even ... |