EICO ST40 find...

Discussion in 'Audio Hardware' started by theron d, Jun 11, 2018.

  1. theron d

    theron d Forum Resident Thread Starter

    Location:
    Baltimore MD
    Yesterday's purchase in the neighborhood. Have not turned on yet. I believe this unit was factory wired since the work looks very good (IMO). Also the GZ34 rectifier tube is smoky grey at the top (see pic) so Im assuming it's bad? Those are Westinghouse 7951 Power Tubes (been looking for some for my Pilot 248B amp which is another recent adventure in itself.) Below are some pics, any feedback greatly appreciated, anyone have and can describe the sound? The small signal tubes are Mullard (Made in Great Britain), except the 12Ax7s which are Teles.

    Description
    The Eico ST40 amplifier was available as a kit or fully wired.

    Specifications
    Power output: 20 watts per channel into 8Ω (stereo)

    Frequency response: 40Hz to 20kHz

    Total harmonic distortion: 1%

    Damping factor: 11

    Input sensitivity: 3mV (MM), 360mV (line)

    Speaker load impedance: 4Ω to 16Ω

    Valve complement: 2 x 12AX7, 4 x 12DW7, 4 x 7591, 1 x GZ34

    Dimensions: 403 x 130 x 333mm

    Weight: 32lbs

    Year: 1960

    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
     
    Last edited: Jun 11, 2018
    Dave, Kyhl and JohnO like this.
  2. theron d

    theron d Forum Resident Thread Starter

    Location:
    Baltimore MD
    [​IMG]

    GZ34 Rectifier Tube looks bad
    [​IMG]
     
    Kyhl likes this.
  3. HiFi Guy 008

    HiFi Guy 008 Forum Resident

    Location:
    Connecticut
    Congratulations. Great pictures. Looks neat. How does it sound?
     
  4. theron d

    theron d Forum Resident Thread Starter

    Location:
    Baltimore MD
    Thanks, have not turned on yet, getting a replacement rectifier tube first. Also there is a local tube tech nearby that I want to look over (he worked on my pilot amp which I linked above)
     
  5. Paul K

    Paul K Forum Resident

    Location:
    Toronto, Canada
    I had this amp.
    It was awesome.
    My first intoduction to the worls of tube ausio.
     
    theron d likes this.
  6. theron d

    theron d Forum Resident Thread Starter

    Location:
    Baltimore MD
    Thanks Paul K :righton: Can you describe the sound?
     
  7. ZenArcher

    ZenArcher Forum Resident

    Location:
    Durham, NC
    If you have a tube tech, you know not to plug it in until he brings it up on a variac, yes? Sorry, I've seen too many disasters...

    Hope you enjoy your new amp!
     
    KT88 likes this.
  8. theron d

    theron d Forum Resident Thread Starter

    Location:
    Baltimore MD
    No I did not, whoops... for the Pilot amp we just fired it up (but this was a different situation where the previous owner had used daily for years). This one a different story, thanks I will inquire...
     
  9. ZenArcher

    ZenArcher Forum Resident

    Location:
    Durham, NC
    Exactly. If a piece has been fitting unused, best not to plug it in until your tech can bring it up slowly. It can help reform capacitors and any fireworks can be smaller...

    You have a very nice find there!
     
  10. theron d

    theron d Forum Resident Thread Starter

    Location:
    Baltimore MD
    thank you much appreciated for the heads up!

    Those Westinghouse 7591's may have to get put into the Pilot 248B for the time being though :)
     
  11. chervokas

    chervokas Forum Resident

    Yup, the vacuum is broken on that tube. It's dead.
     
    KT88 likes this.
  12. HiFi Guy 008

    HiFi Guy 008 Forum Resident

    Location:
    Connecticut
    Just curious. What is it that shows it's broken?
     
  13. allied333

    allied333 Forum Resident

    Location:
    waterford, mi
    White color on top shows tube lost vacuum. All tubes do this with same white color when the tube loses vacuum. It was chrome color before vacuum was lost.
    Anyways, nice find. It is a good amp.
     
    HiFi Guy 008 and theron d like this.
  14. theron d

    theron d Forum Resident Thread Starter

    Location:
    Baltimore MD
    thanks, arranging for local tube tech to look at....
     
  15. chervokas

    chervokas Forum Resident

    As notes above, you get that white gassy coating on the glass when the glass breaks or the vacuun otherwise fails. That's what it looks like. If you ever drop a tube and it cracks, you'll see it happen the second the vacuum pops.
     
  16. theron d

    theron d Forum Resident Thread Starter

    Location:
    Baltimore MD
    (4) 12DW7 / 7247 tubes and (2) 12AX7 / ECC83 tubes that were in the Eico ST40 when purchased. Mullards made in Gt. Britain :thumbsup: (my initial post was wrong and stated the 12AX7s were Teles, nope they are Mullards)

    [​IMG]
    [​IMG]
     
    Last edited: Jun 13, 2018
  17. KT88

    KT88 Forum Resident

    Very nice catch. These are excellent. The rectifier is toast. Probably a lot of the caps under there, and perhaps the main filters in the cans on top. Those shuld likely be replaced before even powering it up. Definitely have a good tech go over it before it is attempted.
    -Bill
     
  18. theron d

    theron d Forum Resident Thread Starter

    Location:
    Baltimore MD
    yes KT88,making arrangements for that with local tube tech! getting those caps replaced with the rectifier tube...fingers crossed!
     
  19. action pact

    action pact ^^ Sandy Warner, "The Exotica Girl"

    That looks like a terrific score!

    This kind of surprises me though... it can't reproduce low bass? Is this correct?
    Frequency response: 40Hz to 20kHz
     

Share This Page