Eico HF-22 rebuild/update

[jaymanaa]

When you're good you're good. Looks fantastic as usual Jim. :thmbsp:

Thanks for posting man, a lot of people don't bother these days. Good Karma on ya. :yes:

 

[ab0ez]

When you're good you're good. Looks fantastic as usual Jim. :thmbsp:

Thanks for posting man, a lot of people don't bother these days. Good Karma on ya. :yes:

Thanks man. I wish more guys would post pictures of their builds as they progress. I sure get some ideas when I see what the really good guys are doing!

 

[dcgillespie]

Looks superb, Jim. If I may though, check the wiring on your input pot. It appears that the hot lead from the input jack and the 10K resistor going to the input stage are reversed on the pot.......

Great thread and build!

Dave

 

[ab0ez]

Nice catch Dave and thanks! My shoulder was killing me last night and it showed....

 

[jaymanaa]

Reminds me of a time I wired a volume pot bass ackwards. You just can't imagine how weird that is unless you actually experience it.

 

[ab0ez]

Reminds me of a time I wired a volume pot bass ackwards. You just can't imagine how weird that is unless you actually experience it.

Been there and done that....and it blew my test speaker when the amp came on at full output!

Let that be a lesson folks, soldering and pain killers don't mix!

 

[jaymanaa]

Been there and done that....and it blew my test speaker when the amp came on at full output!

Let that be a lesson folks, soldering and pain killers don't mix!

Ha, well I guess it's still a better club to be in than the broken cantilever club. I remember the day I joined that club with a dust rag an a Benz Micro. :tears:

 

[chinacave]

I had time today to get the first HF22 stripped down, power transformer bells pulled off and transformer inspected, not too bad. No signs of anything bad happening!

The underside of the chassis has some surface corrosion that will be cleaned off, but it's in pretty good shape for it's age!

Jim- really nice step by step photos! Thanks for enabling us to follow along.

May I ask how you cleaned up the slight rust on the underside so nicely? It looks great. So typical to find that crusty stuff on the inside...

 

[ab0ez]

Jim- really nice step by step photos! Thanks for enabling us to follow along.

May I ask how you cleaned up the slight rust on the underside so nicely? It looks great. So typical to find that crusty stuff on the inside...

Thanks and sure, no problem. I used two orbital pad sanders, one with a square pad and the other with a pie slice shaped pad. Make sure and wear a mask, because I'm sure that dust isn't very good for the lungs. With some 220 grit sander paper the cleanup is a snap. If you like, you can use an even finer grit to give the cleaned surface a polished look.

 

[ab0ez]

Got the output transformer wired in (to include 100 ohm screen stopper resistors) and decided where to place the cathode resistor and bypass caps. This will be the last update until, most likely, Friday or Saturday. Now, where did I put those 750pF 1000V silver mica caps???

 

[ab0ez]

Still waiting for the capacitors to arrive in the mail so I can finish the first filter section of the power supply. In the meantime, the power transformer has been mounted with vibration isolation in mind.

 

[Kegger]

Did you decide to do any mods to the circuit?

 

[Dukiedook]

Looks good, like kegger said, did you decide to improve the circuit a little?

 

[ab0ez]

The power supply is a given. I'm building the rest with some mild-ish tweaks in mind. If I don't like how it sounds, it will be written up that way and then I'll go for the full-blown Williamson conversion.

 

[ab0ez]

The 47uF 450V caps were waiting in the mailbox for me when I got home today. First filter node wired in. Rectifier socket fully wired in. Terminal strips for cathode bias and bypass network mounted. Components rough-fit in. 750pF cap wired in. Eyes cross-eyed. Time for bed!

 

[dcgillespie]

Textbook pics of how it should be done. Super job!

Dave

 

[Dandy]

Textbook pics of how it should be done. Super job!

Dave

+1. We are lucky to belong to this helpful AK community.

 

[ab0ez]

Thanks Dave. I did change the 10K dropping resistor to a 4.7K per your advice. This will be fun to finish it and it's left side brother and check out.

 

[BrokenHill]

Wow! your going to have some super nice amps when your done, where did you get the twisted pair of silver plated wire with Teflon insulation
that you used on the tube heaters? it really makes the wire job look very clean.

I have seen similar wire like you used on e-bay.

 

[ab0ez]

Thank you Sir. As far as the wire goes, I've bought it from Ebay, Amazon and a bunch of other places. I shop around and buy it in larger lengths when I find a really good deal. I've had a big roll of that twisted pair for about 8 years now and I still have a lot of it left!