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st70

  1. SKS

    Wild mods on Dynaco ST70

    Saw this posted on CL near me. https://sfbay.craigslist.org/sby/ele/d/san-jose-dynaco-dynakit-st-70-tube/7370428384.html Filter cap is bigger than the PT (cl post says 20x larger than stock). Has a giant U shaped bus bar, and a bunch of components i cant even identify. On one hand I respect...
    • SKS
    • Thread
    • dynaco st70 tube amp
    • Replies: 26
    • Forum: Tube Audio
  2. M

    Dynaco ST70 low bias - help needed

    Recently purchased a dynaco st70 and everything appears to work - sound seems decent, but measurements from unit aren’t aligning with manual. Quad cap, bias knobs and caps and selenium rectifier appear to have been replaced. bias measurements are low also - ~0.36 images and measurements...
  3. David_NC

    Dynaco ST-70 - Upgrade Time?

    I bought this ST-70 about 2 years from a local GW. It came with good T-S 7199's and Philips EL34 / 6CA7's. It's in great shape and worked well, but I replaced the selenium rectifier, multi can cap, caps and resistors underneath, and the six caps on the driver board before putting it into use...
  4. zastin17

    "Tube life" Anxiety Caused By Using My Amplifier

    So something has been really driving me crazy!! And that is using my Tube Amplfier, and finding myself way overally worrying about the tubes on my Dynaco St-70. (Which I fully restored) I love the sound, and I love everything about tubes and I'm a bit "emotionally" Obsessed with them and get...
    • zastin17
    • Thread
    • amp anxiety life st70 tube valve
    • Replies: 134
    • Forum: Tube Audio
  5. zastin17

    Dynaco ST-70, What an Amazing Amp!!

    So I got myself an early Christmas present. And I am very happy I did!! What an incredible midrange, and beautifull highs. So diffrent from anything I've heared, but is so fun to listen too. Sooo holographic, so mutch coherent texture. The sound has a physical presence that is very, very real...
  6. R

    Thoughts on restoring a Dynaco ST70

    Hi everyone, I recently came in possession of an ST70 factory wired, all original components. Other than a hum in one of the channels that I traced to the 7199 tube on one side, it's fully functional. I'm very comfortable around electronics but I am relatively new to tubes. I want to ask you...
    • radu_c
    • Thread
    • 7199 dynaco gz34 restoration st70 tubes
    • Replies: 62
    • Forum: Tube Audio
  7. J RR

    Yet another St70 issue

    Hey all tubers! Background: ST-70 with new board, can cap, bias circuit, selenium replaced diode, new Power transformer (about a year old, all of it). Started a low buzz a few days ago. Replaced all tubes: no go. Measurements: Can cap: A (Square): 227VDC B (triangle): 282VDC C (blank): 324VDC...
    • J RR
    • Thread
    • dynakit st-70 st70
    • Replies: 26
    • Forum: Tube Audio
  8. T

    Dynakit ST70

    Hey everyone, I just purchased a Dynakit ST70 Amp along with a PAS-2 PreAmp, and FM-1 Tuner. I am looking to restore them to original condition and this is the thread tor the ST70. I am looking for tips, tricks, and help to bring it back to life. My intentions are to replace capacitors and keep...
  9. J

    Dynaco ST70 Abbreviated Restoration video

    Here is the non-technical artistic version of the ST-70 amplifier restoration video for all to enjoy edited from the several full length videos that made up the original restoration. I make several of such videos a year for larger projects.
    • JRUBIN
    • Thread
    • dyna dynaco restoration st70
    • Replies: 0
    • Forum: Tube Audio
  10. FireGuruMN

    Dynaco ST70 Mystery Modification

    I recently acquired (finally) a Dynaco ST70 for a reasonable expenditure. I intend to do the obvious things like replace defective caps and clean the pots. And replace the ORIGINAL Dynaco output tubes. But after cleaning out the spider webs I found some unwelcomed modifications. Here is a...
  11. poorbastards

    Dynaco St70 hum. Not so subtle on my Klipsch kg4.2s!

    I bought a st70 a few days ago. There wasn't any hum when I first used it but wanted to wait until I had installed a potentiometer to fully test/use it. The prior owner installed a different switch for power and that sparked on me last night,I went in and cleaned up the connections and there is...
  12. CoolOhm

    Help Needed with a New VTA-70

    Hello Fellow AK'ers: Well I finally went out and got myself a tube amp! I have never heard one before and the curiosity got the better of me. Had my heart set on an Dyna ST-35 but this VTA-70 came up and the price was right... Looking for some opinions and advice prior to powering it up and...
    • CoolOhm
    • Thread
    • dynaco st-70 st70 vta-70 vta70
    • Replies: 15
    • Forum: Tube Audio
  13. J

    Dynakit ST70 Complete restoration Project

    This is the beginning of what is the second phase of a greater project going back several years, that being the initial salvaging of this amplifier after being found stored in a Florida attic for over 40 years. For this effort a complete video series exists where the amplifier was brought to a...
    • JRUBIN
    • Thread
    • dyna dynaco dynaco st-70 dynakit st70 restoration st-70 st70
    • Replies: 15
    • Forum: Tube Audio
  14. J

    DYNA ST-70 Harmonic Distortion Testing using all 1960's Heathkit Tube Technology

    In this video I will demonstrate harmonic distortion testing of my Dynaco ST 70 amplifier using all Heathkit tube gear from the 50's and 60's. This demonstration will show the THD produced from this amplifier at 2KHZ using three different power inputs. The equipment used includes: Heathkit...
    • JRUBIN
    • Thread
    • dyna dynaco heathkit ig-72 ig72 im-12 im12 st-70 st70
    • Replies: 15
    • Forum: Tube Audio
  15. cocovinyl176

    Trade MC250 SS for Dynaco st70 Tubes?

    Hello all, I know some of you will be bias in one way or another regarding SS vs Tube, but thought I'd throw this out to the AudioKarma world to gather some thoughts. A trade: Mcintosh MC250 for Dynaco st70 Both units are cosmetically 9/10 with zero rust or pitting Both units are in its...
  16. F

    Thinking about buying this Dynaco ST70, is it worth it for a beginner?

    Hey guys, I've never been on this forum before but I was refered here and thought you might have some good info. I can get my hands on a ST70 for around $350, but only until tomorrow. I've been really interested in getting into speaker set ups and especially tube amps as a fledgling headphone...
    • Fredark
    • Thread
    • beginner buying diy dynaco dynaco st70 fix st70 tube tube amp used
    • Replies: 4
    • Forum: Dollars and Sense
  17. Cabdiver

    Dynaco ST70 rebuild with Triode boards

    Hello everyone. I'm a newbie with more enthusiasm than good sense who bought the Triode E input (Driver) and capacitor (power) boards in an attempt to bring an ST70 back to life. I've completed the boards and placed them in position on the chassis, but have gotten stuck on the final stages of...
  18. J

    ST70 7199 / 6GH8A amplitude vs frequency

    Ive posted a 1 off video showing my issue of the amplitude change of the 7199 outputs in which the change increases with the frequency. I found something, however even though it corrects the amplitude, the phase does not align, tested with both a 7199 and a 6GH8A Surely this is masking another...
    • JRUBIN
    • Thread
    • 6gh8a 7199 frequency imbalance phase st70
    • Replies: 102
    • Forum: Tube Audio
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