Eico ST-40 pick up. My first Eico

sanford12

sanford12

Old Stuff New Stuff As long as it's Good Stuff
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Picked this up Sunday at the Antique Radio Club of Illinois meet in Chicago along with a nice Philco "Hippo" bakelite radio.

It was recapped and came with 4 strong RCA 7591's, 4 good Mullard 12DW7's, a couple of US 12AX7's and a Chinese 5AR4. It's very quiet and everything seems to work but the loudness switch is a little finicky. There is a fix for it but the link to the site where the fix was at is broken. I'll look some more and maybe I'll find it. Diana Krall was playing while the pictures were taken, very nice. It has good bass and the mids and highs sound good as well. I'll re access after I try it the main system. It will be interesting to see how it compares to the Sansui 1000A's 7591 sound.

Here's the pictures

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That's a beaut.
Operates mostly in Class A and has a very sweet and involving tone.
It's a science project to figure out how to get the speakers to work in stereo, and to figure out where to plug the inputs.

The only kind of wierdness I found was having the on/off switch be in the treble control. But I liked the one I had.
Yours looks like I fantasized mine would look some day, but never did.

I used to be able to scratch the 12DW7s and hear it in the speakers.
Congrats. I hope that one lives up to the promise I truly heard in mine.
 
Wow! That's beautiful, you are a lucky guy. If it sounds anywhere as nice as the EF81 I just overhauled for Special Idiot you are in for a treat. I've been giving him some cock and bull story about having to test the phono, but really I just don't want to let it go just yet.:music: BTW, don't tell him.
 
They wired the Loudness switch as an "attenuator plus loudness compensation". Nobody else did... so you may prefer to rewire it to the more conventional type. I think I posted here on the HF-85 a few months ago.
 
audiodon said:
That's a beaut.
Operates mostly in Class A and has a very sweet and involving tone.
It's a science project to figure out how to get the speakers to work in stereo, and to figure out where to plug the inputs.

The only kind of wierdness I found was having the on/off switch be in the treble control. But I liked the one I had.
Yours looks like I fantasized mine would look some day, but never did.

I used to be able to scratch the 12DW7s and hear it in the speakers.
Congrats. I hope that one lives up to the promise I truly heard in mine.
Click to expand...

Pretty much everything on this amp was designed to confuse. I've never had an amp that took me 5 minutes to figure how to hook the speakers. Your right the inputs were a real treat also. With that said I think the sound will justify it's quirkiness

jaymanaa said:
Wow! That's beautiful, you are a lucky guy. If it sounds anywhere as nice as the EF81 I just overhauled for Special Idiot you are in for a treat. I've been giving him some cock and bull story about having to test the phono, but really I just don't want to let it go just yet.:music: BTW, don't tell him.
Click to expand...
I'll put in the main system this week and give it a whirl. Maybe if you keep EF81 long enough he'll forget where it's at. What with all the gear we go through it could happen.

Tom Bavis said:
They wired the Loudness switch as an "attenuator plus loudness compensation". Nobody else did... so you may prefer to rewire it to the more conventional type. I think I posted here on the HF-85 a few months ago.
Click to expand...

I've never seen anything like it and the way it's working, I don't know if it's correct. In the bottom position you have volume change throughout the range just like normal but with the loudness in the on position(up) until you reach the 12:00 there is no increase in volume then just past and bam it's there. Normal operation?
 
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Bear in mind that a lot of these were built as kits, and the guys who built these often just wired the speaker outs normally. That's how my Eico ST-70 is.
 
And the EICO ST-70 is very similar to the ST-40, just a little larger output transformers and a little more output power. For more output, it may have higher B+; I don't have a schematic.

As for the loudness switch, there was a big controversy about the engineers being upset with the company and the design was intentionally done incorrectly. If you search the web, there is a very simple rewire that can be done, I think with different, easily purchased components, that will make it work just fine.

"Nice catch!" as they say...
 
My bro-in-law has a HF 81 and loves it. He calls it "the little rust bucket" and pairs it with LaScalas. I would imagine it difficult to integrate with most speaker pairings , especially due to its low wattage and speaker efficiency ratings. That said, he swears by it.
 
I'd posted to another AK'er about the loudness switch mod and other info concerning his ST-70 which applies to the ST-40 also, so I'll paste it here:

The best source for information on this amp is at the Eico Tube Amp Fan Club website in Yahoo Groups. Once you join you can access the information for this amplifier from the 'Files' and 'Links' sections on the left-hand column.
The loudness mod you seek can be found in the links section and is under 'The Wayback Machine..................'. There's lots of info available on your amp, so have at it and enjoy.

Larry
 
Hey...

I also heard about the "operates mostly in class-A" part...a few years ago one of my local tubetech-friends went as far as to say that the ST-40 was the EICO to find. At the time I was looking for an integrated to overhaul and keep.

Nice amp. :thmbsp::thmbsp:
 
a buddy of mine has a st40 and while he has lots of audio gear i found it interesting that the only piece of gear his wife liked was the st40 and told him never to sell it.

sanford12 it looks like your missing a knob.that's one thing i hate and i think i can help you out.i picked up a bunch at a hamfest years ago and just might have the correct one for your st40 but there were 2 color schemes for the same knobs.i'll have a look this weekend and if i can find the ones i have i'll send it to you for the cost of shipping.enjoy the new toy :thmbsp:
 
radioactive said:
a buddy of mine has a st40 and while he has lots of audio gear i found it interesting that the only piece of gear his wife liked was the st40 and told him never to sell it.

sanford12 it looks like your missing a knob.that's one thing i hate and i think i can help you out.i picked up a bunch at a hamfest years ago and just might have the correct one for your st40 but there were 2 color schemes for the same knobs.i'll have a look this weekend and if i can find the ones i have i'll send it to you for the cost of shipping.enjoy the new toy :thmbsp:
Click to expand...

Radioactive,

I am also in need of a new knob for my Eico ST-70 (the selector knob), which is missing the light color plate. Do you have a knob that matches the ones I have? Thanks in advance.
 

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Nice amp and in very clean condition. If you have time, it would be interesting to see a photo of under the hood.

I was just listening to mine, which I sort of have in storage, this evening. It was sold to me as broken, but all it needed was a new rectifier tube and fuse--and then recapping and the loudness mod and a missing knob!

The ST40 is sometimes seen as the lowest of the Eico range, but it is very easy to listen to. The only issue is the less common tubes.
 
idadude said:
I'd posted to another AK'er about the loudness switch mod and other info concerning his ST-70 which applies to the ST-40 also, so I'll paste it here:

The best source for information on this amp is at the Eico Tube Amp Fan Club website in Yahoo Groups. Once you join you can access the information for this amplifier from the 'Files' and 'Links' sections on the left-hand column.
The loudness mod you seek can be found in the links section and is under 'The Wayback Machine..................'. There's lots of info available on your amp, so have at it and enjoy.

Larry
Click to expand...

Thanks for the info. It got me where I needed to go. I'll do the loudness switch mod shortly. The switch acts just as described in the article.
Here is the link to the ST-40 & 70 mods page.
http://web.archive.org/web/20050212191916/home.netcarrier.com/~rstevens/st-40.html

Dandy said:
Nice amp and in very clean condition. If you have time, it would be interesting to see a photo of under the hood.

I was just listening to mine, which I sort of have in storage, this evening. It was sold to me as broken, but all it needed was a new rectifier tube and fuse--and then recapping and the loudness mod and a missing knob!

The ST40 is sometimes seen as the lowest of the Eico range, but it is very easy to listen to. The only issue is the less common tubes.
Click to expand...
I'll do that.
 
Sweet looker there. I'll agree that EICO had some real headscratcher designs. Some of their ham gear puzzles people to this day. Enjoy!
 
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