Got me an Eico HF-81 worked by NosValves

vaathi

baski
Subscriber
Hi all..
I picked up Eico HF-81 which has work done by NosValves decade back.. I am yet to power it up since it was unused for 5-6 years now. Is variac only to bring it or should I blindly trust NosValves work and plug it in. Also it did have Mullard tubes with Black lettering. Is it Mullard reissue or old mullards?

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I have both DBT and Variac... I was thinking of connecting DBT to Variac and slowly bringing it up.. Do let me know if I am missing something...
 
I've never heard of Mullards with black labeling, original or reissue (except the date/production codes on vintage tubes). I've seen reissue Telefunkens with black labels (which are selected, cryo-treated JJs IIRC). Any pictures of the tubes in question?
 
I've never heard of Mullards with black labeling, original or reissue (except the date/production codes on vintage tubes). I've seen reissue Telefunkens with black labels (which are selected, cryo-treated JJs IIRC). Any pictures of the tubes in question?

I may have jumped the gun here or I am seeing things or my eyesight is not 20 year old anymore.. Anyway It is grey/white lettering and it is made in Russia.. I guess it Mullard Reissue tubes. I dont know how good this tube is. I will try to bring it over the weekend and do it slowly... Any input is appreciated. Do I need to pull out all the tubes when I bring it up in the variac or not?

Image of the EL84 in the amp.

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It doesn't look like the multi section can capacitor was part of the rebuild so I would definitely replace it.

My recently acquired Dynaco ST-70 seemed to be working fine with the original can cap. I replaced it anyway and once the old cap was out of circuit I wasn't measuring any capacitance in one of the four sections.

If you have a variac, by all means, bring it up on the variac.
 
NOSValves is a well known and professional tech, so I think you may be being over cautious. No harm in that of course.

If the multi-section can has not been replaced, it's time to do this. But check whether this has been done. Assuming this is good, or replaced, I'd just use a dim bulb tester before a first power-up.
 
Use your variac. This has nothing to do with who did the work on it. It has to do with the amount of time that has passed since it has been used.
 
Craig (NOSValves) is a member here and you could always contact him...I'd go the safe rather than sorry route...by the way, I also have a NOSValves rebuilt 1959 vintage HF-81 and love it...

Bill
 
+1 on the Variac, as the parts list doesn't include the filter cap. That being said, Craig probably found it didn't need replacing, so perhaps thst's still the case a few years later.
Replacing it couldn't hurt much except your wallet, but you might want to look into using single caps under the chassis if there is room; there seems to be plenty adjacent for 3 single caps. They are always less costly, allow for some tweaking as far as increased values, and allow you to leave the can on top for looks once you disconnect it.

This is a well respected amp and I bet there's sites that have addressed this already you can follow.

Nice amp; it's an EL84 classic and should serve you well.
 
I'd do the variac route, just to be on the safe side. Also, make sure you have a pair of "test" speakers or a "dummy load" hooked up when you bring it up.
 
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