ampage
Tube Amps / Music Electronics
For current discussions, please visit Music Electronics Forum. The sunn still shines online!

ampage archive

Vintage threads from the first ten years

Search for:  Mode:  

6L6 Deluxe suggestions

6/11/2004 2:25 AM
Tedd
6L6 Deluxe suggestions
Hello,  
 
I have been lurking on this site to learn a few things and build my second amp. I built a deluxe amp using the iron from a crappy knight stereo amp built using 6V6s (2 per channel PP). Being a cheapskate I pulled everything from the old amp (recycling is good)and built it using a Hammond aluminum chassis but did use a weber fiberboard and mostly new caps and resistors. The hitch was that the amp was built for 4 6V6 tubes and used an EZ81 rectifier. I essentially built the amp to the deluxe circuit using the EZ81 and it sounds quite nice.  
 
The problem, which I must admit I did not anticipate is the use of the oversized PT. With 6V6 tubes I get a cathode bias of 22.1 V and a plate voltage of 387.5-22.1=365.4 V. I am using a 258 ohm resistor which gives about 85 mA, very hot. I tried 6L6 tubes and got a cathode voltage of 26.2 V and a plate voltage of 378.3-26.2 = 352.1 V. So 101 mA and I calculate 35 watts. Still hot but more reasonable.  
 
I have decided that I like the way it sounds with 6L6s, so I am going to buy a new OT to match the wattage. In the mean time, what damage might I do to the amp by using the OT designed for 6V6 output? (I am not too worried about the OT itself as I have two).  
 
I also have too much gain in the amp such that the volume controls are very sensitive. I was thinking about putting a resistor in the circuit between the second gain and the PI. I have already replaced the 0.1 uf caps with 0.022 uf caps which dropped some gain and made my les pauls sound less woofy. I was also want to drop the plate voltage using a zener mod to lower the power.  
 
Tedd

 
Replies:
Bruce /Mission Amps Sounds to me like you're doing fine... -- 6/11/2004 5:30 AM