Haven't posted in awhile, hope everyone is doing well. I was privileged to own a pair of Mark IV amplifiers for a year or two and I became a tube addict!! Is there a tube-o-holics anonymous out there? If there was I would need to go! Well I sold the custom pair of Mark IV's that I had built, and decided to graduate up to something a little more grand, possibly the Mark III's, but I was thinking since the Mark IV's are basically the ST-70 on steroids!! I would need to build a pair of Mark III's on Steroids, so my idea is this, fully regulated front end B+, DC heaters to the front end, and a beefier power supply. Have the power supply PCB ready to go, and main board, just need a chassis now to house it in. Any thoughts?
4 posters
Mark III on steroids!!
j beede- Posts : 473
Join date : 2011-02-07
Location : California
- Post n°2
Re: Mark III on steroids!!
I am a fan of the MkIII. I don't think the power supply has any serious weakness other than the quad cap's marginal working voltage. I replaced the quad cap with an array of series pairs of modern (compact) 450WVDC caps with balancing resistors. This enables solid state rectification and higher B+ when running KT-88 etc.
GP49- Posts : 792
Join date : 2009-04-30
Location : East of the sun and west of the moon
- Post n°3
Re: Mark III on steroids!!
Good comment about modern capacitors. The era of the plasma big-screen TV has come and gone, but with it came renewed production of large electrolytic capacitors of 350-450 volt ratings, easily adapted, as J Beede described, to tube amplifier power supplies...if you have the space available.
sKiZo- Posts : 1530
Join date : 2013-04-01
Location : Michigan USA
- Post n°4
Re: Mark III on steroids!!
The era of the plasma big-screen TV has come and gone, but with it came renewed production of large electrolytic capacitors of 350-450 volt ratings
Can I take that as a "get em while they're hot" kinda thang? Wonder just how long they'll still be available as a major application slides into history ...
Can I take that as a "get em while they're hot" kinda thang? Wonder just how long they'll still be available as a major application slides into history ...
denny9167- Posts : 151
Join date : 2011-05-09
Age : 56
Location : Texas
- Post n°5
Re: Mark III on steroids!!
sKiZo wrote:The era of the plasma big-screen TV has come and gone, but with it came renewed production of large electrolytic capacitors of 350-450 volt ratings
Can I take that as a "get em while they're hot" kinda thang? Wonder just how long they'll still be available as a major application slides into history ...
Hopefully as the interest in tube audio continues to grow, the demand for high-voltage electrolytics will also continue!
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