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Title: Half power switch for 18 watt. Post by: Aesg81 on February 18, 2010, 05:13:02 AM Is this simple to do? Like with the 36 watt. Or is the vvr option better?
Thank you all for any input. Title: Re: Half power switch for 18 watt. Post by: grod915 on February 18, 2010, 10:57:49 AM You need a multiple of two power tubes operating in a push-pull amp.(2, 4, 6, etc.) Because a 36 watt amp has four tubes, half (two) can be shut down for half power. So no, you cannot do this with an 18 watt amp. You could do the Triode/Pentode mode switch thing but it's not really the same. I've heard good things about Mr. Hall's VVR mod, that's probably your best bet.
Title: Re: Half power switch for 18 watt. Post by: cmoore on February 19, 2010, 02:24:35 AM You need a multiple of two power tubes operating in a push-pull amp.(2, 4, 6, etc.) Because a 36 watt amp has four tubes, half (two) can be shut down for half power. So no, you cannot do this with an 18 watt amp. You could do the Triode/Pentode mode switch thing but it's not really the same. I've heard good things about Mr. Hall's VVR mod, that's probably your best bet. You could fill a book with information regarding the topics that "grod915" has discussed. I have heard a lot of "Half Power" switches over the years, and a lot of guys have praised them. I just have never felt they worked that well. And do not confuse half power with half volume. Again, "grod915" has mentioned a VVR. I think those are a better solution for most circumstances. Of course, the best solution is trying as many different options as you can, so your ears can have a vote.Good Luck Title: Re: Half power switch for 18 watt. Post by: Udonitron on June 02, 2010, 10:50:10 PM I had Nik make mine with a VVR, it rocks!! Sure at lower wattages it breaks up very quickly but being able to play it at bedroom levels is the bee's knees baby! Nik, you know I love you eh? LOL ;D
Title: Re: Half power switch for 18 watt. Post by: Tone Control on October 15, 2010, 08:02:30 AM I had Nik make mine with a VVR, it rocks!! Sure at lower wattages it breaks up very quickly but being able to play it at bedroom levels is the bee's knees baby! Nik, you know I love you eh? LOL ;D I've had 4 amps made with power scaling or VVR, and to me it's no better than a THD hotplate (Note: it only works if you have a master vol, otherwise it's horribly fizzy). Triode mode is no worse I think. I recommend PPIMV + THD hotplate, but really, you never get the proper tone at quieter volume. Even the half power on the 4 valve models is not the same. I have it on a DZ30, on half power, the headroom is gone, the rectifier is over-spec and the output transformer is not saturating the same way, a different sound, but the closest to full power. But --- not a big decrease in volume. For quiet levels with real tone, the best solution is an ISO cab, and run you mic'd output through your recording setup into monitors or headphones. The Randall one is the best I've tried, but it's single skin and the speaker is attached to the outer chassis. Best to build one yourself. Double skinned is best with insulation in between, or convert a cupboard (closet?) into an ISO room. I have an Axetrak too. It's convenient, but the tone is poor. You can rescue it a little with EQ, but best to use 12" speakers Title: Re: Half power switch for 18 watt. Post by: arledgesc on November 08, 2010, 03:06:26 PM I've had good luck with PPIMV on my amps. They sound best on the upper half of the control. So everything is a trade off. They are cheap and easy to install especially on the 18W amps. Take a look in the mods section on the Ceriatone web site. The 1M ohm pot across the power tube grids is all it takes for these amps. If it doesn't work out two snips of a wire cutter and you are back to normal. Scott
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