Let me start by warning you there may be voltages as high as 1000
volts in the power supply and near the output stages, so stand on dry
rubber mat, and avoid touching anything including the chassis with the
power on. I suggest you try replacing one tube at a time. Put the
original back in if you think the quality got even slightly worse. You
need to test each tube at both low and high volume. Stop if you get an
improvement. It is unlikely that parts with a tighter tolerance will
improve the fidelity, but different values may produce the over driven
sound you like at low volume. The new value may however produce bad
results at high volume. Generally resistors need more ohms to produce
the over driven sound at low volume. You can similate a higher
resistance by connecting a million ohm resistor in series with a 9
volt battery (or perhaps 2 each 9 volt batteries to get 18 volts). You
can then bridge each resistor with the battery resistor combo. Most
trys will produce no effect, but one may produce a change that you
like. You need to swap the battery/resistor connection for each test
to reverse the polarity. If you don't get a result you want, try again
with about 200,000 ohms and 18 volts or even 27 volts. The resistor
needs to be rated 2 watts or more, and should be connected for only a
few seconds before you check to see if the resistor is hot. Do not
touch the resistor while it is connected to the amp as you could get a
dangerous shock. The resistor will stay warm for at least a minute. A
warm resistor means you may damage something in your amp, so don't
connect less about a million ohms to that resistor for more than a few
seconds until you have determined that the 200,000 ohm resistor does
not get hot. When you find a resistor that produces an effect you
like, disconnect one end of that resistor, and instal temporarily a
resistor with 2 or 3 or or 4 times as much resistance to see if it
behaves some what like the resistor battery did. (There is a slight
chance that you need a resistor smaller by about 40%. Check frequntly
for resistors that may be getting hot most anywhere in the amp if you
get down to 1/2 or less of an original value. If you like the effect,
add a switch so you can select either the original value or the new
value. If you play for old folks, they won't care for the over driven
sound or much of anything other than high fidelity. If your Lanley is
sterio, you should find the same resistor in the other channel and add
a switch and resistor there. Hopefully the two channels will behave
the same. If a resistor somewhere else in the amp gets hot (warm is
OK) replace it with the same resistance value about double the watts
rating. Radio Shack carries resistors, or you can remove them from
junked electronics equipment. Neil |
