Eico ST-70 Makeover Thread

[BuzzK]

I decided to simplify the messy selector switch circuit down to three inputs: phono, aux, and tuner (or CD). This allowed me to use an $8.00 switch with PCB included from Broskie. His PCB is well-marked, making the wiring of the switch a breeze.

I'm using some silver-plated copper coax wire for the signal connections.

Here is a photo of the old switch on the left, and the new one on the right.

 

[Hofy]

Do we ever get to see the finished project? I have an Eico ST-70 that my grandfather built in 1962 that I have been wanting to rebuild for years. Both your threads offer so much in getting me started on doing this. Thanks.

 

[BuzzK]

My friend sent me a photo of the front panel he designed on the ST-70 (the musical notes are from the song "Bad to the Bone"). He later replaced the black knobs with gold ones. It's finished and making music, but that's all of the photos I've got for THAT one.

He doesn't show the cage that he designed, but I will . . . I'm building one from scratch myself, but it will have a black color scheme. Photos of that project are on this thread:

http://www.audiokarma.org/forums/showthread.php?t=392447&highlight=eico+rebuild

I will have a lot of photos of the process including the finished product. Time to add a few more . . . ;-)

 

[Dandy]

In the long run, I'd like to do the same to my ST40. I've got the popcorn out...

 

[BuzzK]

My friend made extra front and rear panels, so if anyone is interested, PM me and I'll give you his contact info. I can't speak for prices, etc. but they should be reasonable.

 

[Hofy]

Weird. My other reply just disappeared. Anyway, thanks for posting an update, Buzz.
I look forward to seeing to finished results inside and out. Also, thank you for the plan for the new read apron.

Both threads are a great inspiration to get me going. Now all I need is spare time. (Swamped at work.) I will be posting my own thread of the progress I make when I get started.

 

[BuzzK]

To try to minimize confusion (don't know that it is possible!) I'll post updates to the other thread cited earlier, i.e. the scratch-build of the ST-70.

An ST-40 / ST-70 is a very competent amp when simplified and upgraded. In my opinion, it's worth the time, or else I wouldn't be investing mine.

If you're standing on the pier, it's time to jump into the water.

;-)

 

[BuzzK]

My buddy dropped over with the amp, and I took some more photos of it.

He does nice work with the sheet metal.

Remember, this was an ST-70!

 

[Foamman75]

My buddy dropped over with the amp, and I took some more photos of it.

He does nice work with the sheet metal.

Remember, this was an ST-70!

How did he get the writing on the sheet metal?

 

[jaguar06]

Quite a beautiful piece out of something originally a bit homely (I have one).

 

[shelly_d]

Really nice. I envy you your skills at building.

Shelly_D

 

[BuzzK]

How did he get the writing on the sheet metal?

Silkscreen.

 

[bktheking]

Sweet build!

 

[klamsoss]

Buzz, I know this is a VERY old thread, but I've just picked up an ST-70, and over the course of familiarizing myself with the updates I need to perform, I found this thread. Your unit is AMAZING looking. Truly impressive. I would be interested in discussing some of the mods you did over the next few months once I have a chance to get mine on the bench.
Do you still have most of the info from this? A lot of the links provided in this thread are now dead, so some of the upgrades/mods aren't 100% clear. I'm familiar with the tronola suite of revisions and I plan to implement those. I also have seen/read about the KT-88 half impedance mod which can get 70wpc out of this iron (which I'm also considering somewhere down the line), but I think I may need to get more in-depth on the 4ohm tap issue, sorting out the confusing.... hell.. just the entire back panel, and possibly adding both a preamp-out, and preamp-in set of jacks (so this can be used as a power amp fed by an external preamp, OR a preamp feeding an external power amp).

 

[BuzzK]

Buzz, I know this is a VERY old thread.

Yes, I almost missed it! Might be good to send me a PM to get my attention as I am likely to overlook things.

Yes, I have schematics on the work that I've done, and I'd be happy to send them to you. PM me with your e-mail address and any other questions you might have. I did many of the Tronola mods but I also added Dave Gillespie's EFB™ circuitry and tried some other things too.


Jon

 

[klamsoss]

Jones, many thanks! As soon as I have my Fisher FM-100B sorted out, I'll have the eico on the bench! I'll be in touch!

 

[hob]

My buddy dropped over with the amp, and I took some more photos of it.

He does nice work with the sheet metal.

Remember, this was an ST-70!

Clean, clean work. If you ever thought an ST70 could look beautiful! Nice job, congrats.