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Graziano
25th September 2012, 10:10 AM
Earlier this year my nephew was after a valve guitar amp and after picking up a box of 6CM5 valves fairly cheaply, I had a look round on the 'net for amp projects based around these valves and found: ECONOMICAL VALVE BASED AUDIO POWER AMPLIFIER (http://www.vk6fh.com/vk6fh/ECONOMICAL%20VALVE%20BASED%20AUDIO%20POWER%20AMPLIFIER.htm) and Grant Wills (http://home.alphalink.com.au/~cambie/6AN8amp/Grant_Wills_6CM5amp.htm)

I built a stereo version of the first amplifier fairly cheaply, probably well under $200 as I had most of the parts lying around already. It was fairly straight forward to make and after letting a few guitar players try it out the general consensus was that it was no good as a guitar amp: it sounded "too clean" and "no distortion there" which made sense as I built it with a fairly stiff power supply with plenty of 47 microfarad 400 volt electrolytics. I also used a 20 Watt PA transformer instead of the 15 Watt unit for the later guitar amp which should extend the ful power bandwidth a bit.

http://www.woodworkforums.com/attachments/f99/234077d1348528115-valve-amp-project-6cm5-amp15a.jpg

petersemple
25th September 2012, 11:18 AM
Nice. I bet you could get it to distort too - just need to plug a lot of gain into the front end...

Graziano
25th September 2012, 08:55 PM
Nice. I bet you could get it to distort too - just need to plug a lot of gain into the front end...

I do have to play around with the guitar amp version a bit to get some distortion happening, might try a cascode stage input and go from there.