- Different tubes do make a difference! - 3 Updates
- Broan QS2 range hood fan control - 2 Updates
- cmsg cancel <34838b98-0e4a-49ac-b468-9a362f7eb841o@googlegroups.com> - 1 Update
| John-Del <ohger1s@gmail.com>: Jul 20 12:17PM -0700 > >I never heard much difference between brands of EL34s, 6CA7s, and even 8417s I've used in my vintage Fisher integrated amp. They all sounded fine until they became flabby with age. > Yeah, I almost had a heart attack when I tried posting the name > brands. How did you know I was being literal? > The better sounding > tubes are Psvane brand tubes. The worse sounding tubes are > Electro-Harmonics. I've used EH EL34s and the 6CA7s in my audio amps and guitar amps, and I thought they were as good as a set of NOS Sylvania 6CA7s I keep on hand. Not to pick on your amp, but I'm not sure that amp is the right device to critique vacuum tubes/valves. Also, I've never listened to (or even seen) a single ended EL34 amp. > bias is adjustable? > Thanks, > Eric I've never actually owned any EL34 amp that was auto bias, so I never compared them. I do know that if you manually bias the outputs too cold, they become class B and sound like crap, which is why I asked. I bias my guitar amp a little hotter than design spec, and my vintage audio amps just a bit on the cool side, and they sound great, but I do rebias them every few months. Before modding your amp, I would measure the cathode current and see where the tube is running. You should be running close to but not over 100% plate dissipation of the tube you are using. You may have to replace your cathode resistors to get there. |
| Phil Allison <pallison49@gmail.com>: Jul 20 10:32PM -0700 et...@whidbey.com wrote: ======================= > This is the amp: https://www.aliexpress.com/i/1988522234.html > The amp has no bias adjustment. ** That is a pile of Chinese "audiophool bait". Cheap and very nasty, a lo-fi joke. Like I already said - your post is a troll. Like all the others you ever posted. .... Phil |
| "pfjw@aol.com" <peterwieck33@gmail.com>: Jul 21 04:32AM -0700 I would be inclined to call the Drongo from Down-Under the only troll here - but that would require it to have magical powers, live in a mountain and steal maidens - all beyond the capacity of this creature. Peter Wieck Melrose Park, PA |
| "G. Paul Ziemba" <unp@ziemba.us>: Jul 20 05:01PM Can anyone explain the electrical principles of the Broan "Quiet Series" (also called "Allure") range hood fan? This unit was made in 2005. There is an electronic control board with three relays that appear to activate three blower speeds (low, medium, high). The blower motor has four wires and there is a 7.5 uF capacitor involved. There are pushbuttons for the three speeds. Speeds 1 and 3 work correctly. After 14 years of use, speed 2 (most frequently used speed) worked only intermittently but did respond to impact adjustment. Now it doesn't even do that. I can hear a relay click for each of the three speeds. but the motor does not turn at all for speed 2. I suspect either failed relay contacts or a bad joint/broken trace, but I haven't gotten a look at the circuit board yet (pending arrival of new membrane button cover which gets destroyed when accessing control board). Anyone know how the motor circuit works? Given that there are only four wires it seems to be a bit more complex than common-cap-1-2-3. Oh, and although it would be easy to throw parts at it, the control board retails for $200. I'd be happer to see if I can resolder or throw a $5 relay at it. thanks! -- G. Paul Ziemba FreeBSD unix: 10:11AM up 50 days, 17:52, 41 users, load averages: 0.16, 0.18, 0.22 |
| "pfjw@aol.com" <peterwieck33@gmail.com>: Jul 21 03:47AM -0700 Three windings on the motor and a common. Most typically, such things are one/two/both, but in your case, it is one/two/three. So: a) determine the motor voltage - likely the same as the line voltage. b) If you can remove the motor from the circuit, do so. c) Determine the common. d) Apply voltage at each winding - additionally, not sequentially - and note if the motor speed increases as expected. f) If so, the relay is likely bad. 15 years is not a bad service life. g) If not, the motor likely bad - and it will be a close-run thing whether to replace the hood or just the motor. Best of luck. Peter Wieck Melrose Park, PA |
| bleachbot <bleachbot@httrack.com>: Jul 21 07:32AM +0200 |
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