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Champ 5C1 with EL34 Vibrato Problem??

6/10/2005 10:13 PM
Champ 5C1 with EL34 Vibrato Problem??
I recently built a 5C1 Champ clone with a 5Y3GT, 6SJ7 but used an EL34 in place of the 6V6GT. I scavenged a power transformer that fed a 6973 P-P (plus 5Y3GT & two 12AX7 tubes) amp and seems very beefy. The amp sound very loud and clean upto about 1/2 volume and then grinds and fries (in a good way up to 9-1/2). When I peg the volume the last little tick to full (10) the amp starts cutting in and out like a vibrato but there is no vibrato circuit.  
Could I being overloading the demand on the 5Y3 to supply the EL34 at max volume? Should I change to a 6L6 or 5881 and rewire the OT to 5,000 ohm?  
I am using three 20 mf filter caps in place of the 8 mf caps called for in the original Fender schematic. The OT is a Hammond 125ESE set at 2,500 ohms into an 8 ohm speaker jack. The rest of the circuit except for the 500 ohm cathode resistor (for a 6V6) is exactly like the schematic. I used a 330 ohm resistor for the EL34 cathode.  
Thanks in advance to all the helpful people at this site! I still have a lot to learn.

Chuck Nothing wrong with the primary impe... -- 6/11/2005 9:34 AM