2. amps-preamps
  3. 1359333599

Tube amps and loads.

My search may have not contained correct phrasing for an answer.
So to you guys;

I have a Scott 299 & 299b. Both restored about 1 1/2 years ago. Unfortunately circumstances have precluded playing with them.
I asked one of our esteemed audio nuts if they needed to be brought up on a variac, answer was no although if I were more comfortable it wouldn't hurt.

Question; if I did use a variac do they need speakers hooked up, or a resistor of some type.

I have read here if amps are powered with no signal a load is unnecessary.
And others have said load is necessary.
Please help.

Best,
Dave
corazon
atmasphere's avatar
atmasphere
11,958 posts
 
Normally Scott amplifier design was pretty forgiving and no load was required. I would not go with that now. If the controls are clean there are probably no worries, but if there is a problem and your output transformer pays the price, then a load to prevent arcing would have seemed like a good idea.

However if its got new caps I would just plug it in with speakers and see how it goes. You might need to run it a day or so before you take it seriously!
marakanetz's avatar
marakanetz
5,473 posts
 
I've worked on Scott amps and they're the easiest tube amps to use. Even with no restoration if the main filter caps do not show the signs of leakage, you may b OK to just turn on. As previously mentioned, use the load resistor at least if you're affraid to damage your speakers, but will less-likely be the case.
hifigeek1
770 posts
 
I usually do not load the output of the amp unless there's an issue with the amp i.e. coupling caps leaking etc.. What I do however is to place shorting plugs at the input.
corazon OP
210 posts
 
Thank you gentlemen for your responses.

All you guys are among my favorite reads.

As suggested, will forego the variac and hook up the AR 7s and give it a whirl! And if the 7s develope a problem, there are always the Boston's!!!

All kidding aside, I'll give it a try this weekend. Will report back afterwards.

Thanks again,

Best

Dave
dill
2,545 posts
 
I have a Scott 299B and like it a lot. If your restoration is about 1 1/2 years old, I would not worry about using a variac, however, I never power up any tube amp without a load connected. You are going to like that 299B. BTW: Do not use EL-84's in the 299B, use 7189's. These can be expensive, however Jim McShane has the Russian 6P14P-EB which is a direct replacement for the 7189, they are affordable and sound great. I replaced my quad set of Telefunken 7189's with them!
More to discover