This is my first diy tube amp and i took some pictures on it. The chassie is made by me in 3mm steel with 10mm alu front. And the hood is made in 2mm steel. It will get black paint on the steel and the front gets natural brushed aluminium.
The tubes are 8 x 6C33C, 2 x ecc82 and 4 x 6n6.
Moore to come.
mats
The tubes are 8 x 6C33C, 2 x ecc82 and 4 x 6n6.
Moore to come.
mats
Attachments
excelent work mats!
Trying to do something like you did... not finished yet...
& for fun!
I'm assuming you're using brand-new 6C33C....
If so, Its VERY important to burn these in before using them 'live' in the amp...
Run 'em heaters Only for 3 to 4 days, with all the other connections (G1, C, P) wired together...
Then run them at 200mA for a 4-5 of hours with no speakers connected to the amp--Use a 20W 8 ohm resistor across speaker outlets on amp, and no input.
Keep an eye on the current for the first hour or two and trim back to 200mA. It will tend to climb over the first 20 mins or so from cold, which is normal for this valve.
This will much reduce the very early failures that can happen with a 'Green' tube....
--Normal mode of failure is arc-over/flash-over internally between Cathode and Anode, and even though the valve may still work after, it should be considered 'scrap' as it will only ever arc over again, and can if there's no fuses destroy a speaker in seconds.....
(I know this can happen, as it happened to me. Luckely I was using a cheapo stereo speaker for testing, so nothing really lost)
After burn-in, these tubes are pretty stable, but still take 20 minutes to thermally stabilise to their final bias-current from cold....
It was the same basic schematic that I re-designed when I made the 'Auto-Bias Inv Futterman' on another thread here, although I re-designed the front end slightly too....
Personally I would reduce the value of the coupling-caps to the 6C33C to 0.22uF....
--10uF in the original A. C. design causes 'blocking/pumping' issues I found on certain tracks and at high power levels....
If so, Its VERY important to burn these in before using them 'live' in the amp...
Run 'em heaters Only for 3 to 4 days, with all the other connections (G1, C, P) wired together...
Then run them at 200mA for a 4-5 of hours with no speakers connected to the amp--Use a 20W 8 ohm resistor across speaker outlets on amp, and no input.
Keep an eye on the current for the first hour or two and trim back to 200mA. It will tend to climb over the first 20 mins or so from cold, which is normal for this valve.
This will much reduce the very early failures that can happen with a 'Green' tube....
--Normal mode of failure is arc-over/flash-over internally between Cathode and Anode, and even though the valve may still work after, it should be considered 'scrap' as it will only ever arc over again, and can if there's no fuses destroy a speaker in seconds.....
(I know this can happen, as it happened to me. Luckely I was using a cheapo stereo speaker for testing, so nothing really lost)
After burn-in, these tubes are pretty stable, but still take 20 minutes to thermally stabilise to their final bias-current from cold....
It was the same basic schematic that I re-designed when I made the 'Auto-Bias Inv Futterman' on another thread here, although I re-designed the front end slightly too....
Personally I would reduce the value of the coupling-caps to the 6C33C to 0.22uF....
--10uF in the original A. C. design causes 'blocking/pumping' issues I found on certain tracks and at high power levels....
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.