[terriblepaulz]

I was recently lucky enough to have a DIY tube amp fall into my lap. It also has speaker taps (cheapo clip types for bare wire). After doing a little searching, I am having trouble getting (definitive) answers to two questions:

1. Leave the amp on 24/7? I suspect that there is no definitve answer.

2. Should I attach some sort of load to the speaker taps?

 

[yashicaman]

I don't think that I'd leave a tube amp on 24/7. I would just turn it on and use it (knowing that it might take 1/2 an hour to warm up and start sounidng really fine). When done, I'd just turn it off (unless I was planning to return to it in an hour or two).

Regarding your 2nd question, I'm not clever enough to comment on it.

Cheers!

 

[Gabe Logan]

Turn off your tube amp when not in use.They can get quite hot and who knows what kind of damage can occur.

 

[roger_s]

It's generally a good idea to run tube amps with a load on the speaker outputs. Fried output transformers can occur otherwise. A couple of 10w resistors from Radio Shack will set you back a couple of bucks and will do the job nicely if you don't want to hook up speakers. Just make sure their leads don't touch the chassis.

 

[sunseeker888]

What kind of design are we talking about here? Pic? Schematic diagram?

You may not need any load resistors if you're using it with headphones. Reason being, most speaker amps actually have a voltage dropping resistor in line with the headphone jack so the outputs don't go haywire when using headphones. Does it have output transformers?

 

[Uncle Erik]

What kind of amp is it? Did you get a schematic with it?

If you don't know, you could tell us what tubes it uses and maybe snap a photo of the insides. Someone here will recognize it or will be able to tell you more about the circuit.

And how do you like it? Pics and impressions, please!

 

[bergman2]

as for leaving it on 24/7...NO, but it depends...personally, I have my audio days and non-audio days...when I know i'm going to listen to my dac-amp-hp setup i turn it on in the afternoon right when i get home from work, let it get warmed up, eat dinner, listen a bit, read, check email, listen some more, and then turn it off when its bed time....as for the speaker-load question, i defer to those with more knowledge on the subject

 

[terriblepaulz]

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif What kind of amp is it? Did you get a schematic with it? If you don't know, you could tell us what tubes it uses and maybe snap a photo of the insides. Someone here will recognize it or will be able to tell you more about the circuit. And how do you like it? Pics and impressions, please!

No schematic. No pics (yet - I'm working on it). The builder described it as an Eric Barbour design, but it's not the same as the design under that name at Headwize. I could not find anything similar after some research, but I am pretty ignorant re: electronics (don't know how to read a schematic).

It has a pair of Raytheon chrome-top 6SN7s, a single Sylvania chrome-top 6BL7 (I think output tube), and a single National Union 6X5 (I think this is the rectifier tube). There are 2 Hammond 25mA/3W output transformers, A Hammond 158Q filter choke, a 4 section (20uf @475 VDC) electrolytic capacitor, and a Hammond 270DAZ power transformer. Mind you, I don't really understand what all those parts do, but that's what I can see on top.

As far as how it sounds, it's pretty distinctly "tuby". I really enjoy my Grados with it. However, there is a pretty noticeable hum. I talked to the builder about this, and he kind of apologized for the fact that this was kind of a quicky project, using some cheapo old parts he had lying around, with too much crammed in the enclosure (it's 10" x 6"). Apparently, the solution to the hum problem was to let him build me a new amp, with a larger enclosure, and better parts

.

When I receive the new amp, I will definitely post some pics and impressions.

 

[cooperpwc]

Don't wear out those tubes! 24 hours all day every day is too much. Generally I am like Bergman: turn it on once in the day and then off when I go to bed. The difference is that I am working out of home so it is often on 12 to 16 hours a day. Still - when I rest, so does it.

 

[sunseeker888]

Agreed. NOS Raytheon and Sylvania tubes are getting more scarce every year; and they ain't making them anymore.