EL84 - Decware inspired build
I really just wanted to post some images in the gallery but couldn't find it. This is an EL84 power amp with attenuator. It is based on the Decware Zen. Tubes are Russian 6N1P and NOS Japanese National EL84s. I recently replaced the rec tube with a Sophia Princess 274B mesh plate. Looks better. Amp plays well through my 98db efficient Beyma 12" concentrics.
I really just wanted to post some images in the gallery but couldn't find it. This is an EL84 power amp with attenuator. It is based on the Decware Zen. Tubes are Russian 6N1P and NOS Japanese National EL84s. I recently replaced the rec tube with a Sophia Princess 274B mesh plate. Looks better. Amp plays well through my 98db efficient Beyma 12" concentrics.
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Not sure what the voltages are now - will measure and post when I get a chance.
I had big hum problems to start with - was using the power supply from another project that had a lot more filtering than the Morrison schematic. Reducing the size of the capacitors to 5 uf input and 50 uf after the choke made a big difference, but to get things really quiet I had to fit 50 ohm pots across the 2a3 heaters with the wiper connected to the cathode bypass cap.
I had big hum problems to start with - was using the power supply from another project that had a lot more filtering than the Morrison schematic. Reducing the size of the capacitors to 5 uf input and 50 uf after the choke made a big difference, but to get things really quiet I had to fit 50 ohm pots across the 2a3 heaters with the wiper connected to the cathode bypass cap.
...finished last summer - C3M Pentode and KT150 UL with global gnfb. Around 18W@10% THD. Works really well, have my other amps collecting dust on the shelves since
Marcus
Outstanding and beautiful! C3m + kt150 is a sure win.
805 and 8000 amplifiers
Photo of the 805amp and 8000amp; i recently made.
The 8000 amp uses a huge Hammond transformer, the 805 amps have C core's made by by Bob Sugden. both amps sound very good, the 805 best as the internal impedance, best suits the Altec horn boxes loaded with well damped RCF15N401's.
Phil
Photo of the 805amp and 8000amp; i recently made.
The 8000 amp uses a huge Hammond transformer, the 805 amps have C core's made by by Bob Sugden. both amps sound very good, the 805 best as the internal impedance, best suits the Altec horn boxes loaded with well damped RCF15N401's.
Phil
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Very nice!
If you use that speaker please do yourself a favour and remove the amp from the top... The tubes will thank you!
Greetings
Very nice!
If you use that speaker please do yourself a favour and remove the amp from the top... The tubes will thank you!
Greetings
Thought you'll write " If you use that speaker please do yourself a favour and remove the mouse from the bassreflex hole"
