Recent content by arts

  1. arts

    Oscilloscope Basics Part 4: Square wave testing and analysis

    When square wave testing any solid state amplifier, be very careful about your power levels when using higher frequencies. It is very easy to destroy an output stage if you push it too hard.
  2. arts

    Test Equipment Sub-Forum

    Good trick with the PS and multimeter. It's amazing how many caps will test good for capacitance & ESR but still fail miserably for leakage. I use a DE-5000 for checking capacitance, ESR & DF. I often need to match up a bunch of caps for tolerance, and this thing is great for that application...
  3. arts

    7591 tubes: What's the difference here?

    The one on the left with the butchered-looking plate material is just sloppy Sylvania manufacturing. I have seen this with many of their power tubes. You should have seen some of their 6550's I've encountered; Yikes! Doesn't affect performance, but looks like s**t. The one on the right has been...
  4. arts

    Test Equipment Sub-Forum

    Same here on the temp rating, especially when dealing with compact or poorly ventilated tube gear, and the 105°C types usually have longer rated lifespan hrs. I like a bit more capacitance to compensate for the cheapy tolerance game, and a bit more voltage never hurts either. Just curious; have...
  5. arts

    Electrolytic capacitor

    I can see we're in the presence of greatness....
  6. arts

    Electrolytic capacitor

    I could easily see that screwing up a tech who wasn't paying really close attention; quick glance, see the big black arrow. Yep, that's the negativeo_O
  7. arts

    Zenith 5AR4 GZ34 Rectifier Tube, Has anyone seen this version? Who made it? Fat Bottle?

    If it has lots of copper showing at the plate seams it's a GE. I believe that they used the three-ply plate material for rectifiers, but saved the five-ply for larger power tubes. The bottle is slightly fatter than a Mullard, but less than a Sylvania. Another excellent tube. Talk about memory...
  8. arts

    Zenith 5AR4 GZ34 Rectifier Tube, Has anyone seen this version? Who made it? Fat Bottle?

    Yep. And especially for any high-demand application, I'd take the Sylvania over the Mullard.
  9. arts

    Zenith 5AR4 GZ34 Rectifier Tube, Has anyone seen this version? Who made it? Fat Bottle?

    That is a Sylvania. In my opinion, likely the best GZ34/5AR4 ever made. Those tubby's are indestructable and last forever. Wish I hadn't wasted so many in guitar amps :(
  10. arts

    Zeners In Series?

    That'll work just fine.
  11. arts

    Power conditioners Snake oil?

    I use a Furman P-1800 PF R . Does it change anything? No idea. But nothing has blown up since I've been using it. ;)
  12. arts

    Things you can only hear on your high end systems

    Tape noise in the Echoplex? Guy I used to be in a band with used a Les Paul with P90's, through an ancient Vox AC50 head and an equally ancient Marshall 4x12 bass cab. I never heard any tape noise. In fact, it's surprising that I can actually hear anything at all after that :oops:
  13. arts

    McIntosh mc240 rebuild times 2

    While you are in there, I would highly recommend that you check all of the carbon composition resistors, as they've usually drifted all over the road by now. I believe that most can be verified in-circuit. Also, if you have a cap tester that can do leakage testing at the necessary voltages, I...
  14. arts

    Took a chance on some Matsushita’s. Glad I did

    Is that an Eames chair lurking to the left?
  15. arts

    Things you can only hear on your high end systems

    I have several pressings, and they range from WOW! to yikes, that sucks... The best? the original party-platter from my teens, despite having more beer and cigarette ash on it than most stages. The worst? The brand new copy from amazon.
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