Yeah, it was the final push that this 64 year old child needed to come out and play. I cleaned off the bench and started testing some ideas. The first step is choose an output tube, and how many of them it will take to get me to 500 WPC. I whipped up some test boards to test the biggest TV sweep tubes that I had sufficient quantities of to build an amp and have spare sets. I will need 4 or 6 tube sets that are sufficiently matched for a PPP amp.
Of course the child in me just had to try to blow a bad tube to pieces. It's really dead now and will meet the hammer soon.
Yes, I really did subject a well used TV tube to brief (long enough for me to read the meters) tests at dissipation levels over 600 watts (650 volts at 900 mA). That one is still alive! When I can devise a more accurate and less abusive testing method I am going to test some NOS tubes.
In parallel with the testing, I have found new and interesting ways to lock up LT Spice, or get totally screwy results out of it. Most of the tube models on the web vary from OK to pretty accurate when you operate them as they were intended. Things like screen drive still don't always simulate correctly, especially things like grid and screen current. Trying to simulate a driver topology capable of 1000 V P-P of output......simulator goes off into never - never land.
Attachments
More power Schotty
In the last video the power supply was being pushed around pretty seriously by the 400 watt tubes so I have now spent a little time fixing that.
https://youtu.be/aORvEjg90Og
In the last video the power supply was being pushed around pretty seriously by the 400 watt tubes so I have now spent a little time fixing that.
https://youtu.be/aORvEjg90Og
More power
And here it is just shy of making the woofers knock. Maximum of about 20 volts modulation in the power supply. Now all I have to do is figure out where to put another couple hundred pounds in my stereo rack....
https://www.youtube.com/watch?v=OrMFP1a3TK8&feature=youtu.be
And here it is just shy of making the woofers knock. Maximum of about 20 volts modulation in the power supply. Now all I have to do is figure out where to put another couple hundred pounds in my stereo rack....
https://www.youtube.com/watch?v=OrMFP1a3TK8&feature=youtu.be
Bass amp
Here is my first test of the gu46 bass amp I have been contemplating. I was rather surprised on how well it performed the first time out.
Now the hard part will be the chassis and all the staging and protection circuits that will be needed to keep it safe.
Next I need to dig out that old pair of 15 inch bass cabs and see how it sounds.
00007 - YouTube
Here is my first test of the gu46 bass amp I have been contemplating. I was rather surprised on how well it performed the first time out.
Now the hard part will be the chassis and all the staging and protection circuits that will be needed to keep it safe.
Next I need to dig out that old pair of 15 inch bass cabs and see how it sounds.
00007 - YouTube
Comnoz, do you have a schematic for your GU-46 amp? I have 4 of these tubes here and plan to go push pull when I find the time.
Thomas
Thomas
I don't have anything on paper yet -but I will.
Really nothing special. Just a transformer interstage driving the grids and four ceramic capacitors to prevent oscillation.
Really nothing special. Just a transformer interstage driving the grids and four ceramic capacitors to prevent oscillation.
Large tube amp now entertainment center
The large tube amp is now a wrap and boy does it sound great.
Here are pictures of it mounted in the rack with the completed GU-46 subwoofer amp.
I may do a video walk around if people are interested.
And here is the source
The large tube amp is now a wrap and boy does it sound great.
Here are pictures of it mounted in the rack with the completed GU-46 subwoofer amp.
I may do a video walk around if people are interested.
And here is the source
An externally hosted image should be here but it was not working when we last tested it.
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