For some time now time i've been planning to make a guitar amp with 2 x EL86 (= 6CW5) push-pull.
I looked at the schematic of the Hagström 620, which has 2 x EL86 in push-pull but i do not trust the schematic i could find on the internet. The screengrids are being fed straight out of the rectifier section, while the anodes are being fed from a point after a fuse and a resistor. I can hardly believe this to be right. If that fuse would blow, it would probably take the EL86's with it.
Because i allready have built a guitar amp with EF86 + 2 x ECL86 pp which is based on the clean channel of the VOX AC15, i now want to build a similar amp with EL86's, so i can hook the two amps up in stereo.
According to Philips datasheets, two EL86's in pp can produce 18,5 Watt at 4,5 % distortion, with Vba = 250 V and Vbg2 = 200 V.
Because the current for the screengrids varies a lot between no signal (2 x 2 mA) and full signal (2 x 13 mA) i plan to stabilize the screenvoltage with 2 ZZ1040 voltage stabilizer tubes.
I want to use the E92CC as the phase inverter because of the chassis i plan to use. The schematic for the phase inverter comes out of a Philips datasheet for the ECC40. Not exactly the same tubes but i am pretty sure it will work with an E92CC.
So here is my plan. I am a bit unsure about the 100K resistor that is connected to the point where the two ZZ1040 are connected to each other. I think this resistor is necessary for making sure that both ZZ1040's will start up.
Any suggestions?
I looked at the schematic of the Hagström 620, which has 2 x EL86 in push-pull but i do not trust the schematic i could find on the internet. The screengrids are being fed straight out of the rectifier section, while the anodes are being fed from a point after a fuse and a resistor. I can hardly believe this to be right. If that fuse would blow, it would probably take the EL86's with it.
Because i allready have built a guitar amp with EF86 + 2 x ECL86 pp which is based on the clean channel of the VOX AC15, i now want to build a similar amp with EL86's, so i can hook the two amps up in stereo.
According to Philips datasheets, two EL86's in pp can produce 18,5 Watt at 4,5 % distortion, with Vba = 250 V and Vbg2 = 200 V.
Because the current for the screengrids varies a lot between no signal (2 x 2 mA) and full signal (2 x 13 mA) i plan to stabilize the screenvoltage with 2 ZZ1040 voltage stabilizer tubes.
I want to use the E92CC as the phase inverter because of the chassis i plan to use. The schematic for the phase inverter comes out of a Philips datasheet for the ECC40. Not exactly the same tubes but i am pretty sure it will work with an E92CC.
So here is my plan. I am a bit unsure about the 100K resistor that is connected to the point where the two ZZ1040 are connected to each other. I think this resistor is necessary for making sure that both ZZ1040's will start up.
Any suggestions?
Attachments
You're right, fusing only the plate supply is a no go! Anyway, I'm convinced it's just a drawing errror: The 6 and 1 should be swapped in the amplifier circuitry (upper right handed corner).
Best regards!
Best regards!
