Quicksilver 8417G User manual

Quicksilver Mono Amps use no circuit boards or transistors. They are hand-wired with the best
parts available. All tubes are run well within their ratings and are protected from turn-on surge.
All these factors contribute to the Quicksilver Mono Amplifiers' excellent reliability.
SPECIAL FEATURES
Tubes should be replaced only with the same type and brand originally in the amplifier. The
8417 output tubes must be replaced as a matched pair and should be purchased through
Quicksilver Audio or a Quicksilver dealer. Quicksilver Output Tubes are "burned-in" for 10
hours prior to matching, and their performance is guaranteed. IMPORTANT: The output
tubes must be biased when replaced (see Initial Turn-on).
TUBE REPLACEMENT
If the 2 amp (slo-blo) fuse blows, replace it with the same type fuse and check the bias. A large
change could indicate a damaged 8417 tube. No change in bias would indicate other
problems, such as poor system grounding, an unstable preamp, a shorted speaker, etc. If
fuse blowing continues these possibilities should be checked. Substituting the 8417s and the
fuse from the other amp will also help to diagnose the problem. If the problem follows the
output tubes then they are probably damaged.
FUSE BLOWING
To insure trouble-free operation from your Quicksilvers, the following tips are recommended.
Connect and disconnect the preamp only when the amps are off. Don't drive the amps hard
when they are cold, or with the speakers disconnected.
NOTE: The output tubes are very sensitive during their first 50 hours of operation.
AVOIDING POTENTIAL PROBLEMS
Screw terminals are used fer speaker connection because of their superior sonic
performance. The output transformer wires are silver soldered directly to the screw strips
eliminating any output wiring. Placing the amp directly behind the speaker with a very short
speaker wire will further improve the performance. The connection to the 4 or 8 ohm tap will
be determined by the rating on the back of your speaker system. The 1 ohm tap is for special
applications only.
SPEAKER CONNECTION
Insert the tubes in their proper sockets. Connect the amp into the system and turn it on. Make
sure the bias is between 80 and 110 ma after 60 seconds or so, and is between110 and 120
ma after 20 minutes or more of operation. Check bias once a month or so.
INITIAL TURN-ON
The Quicksilver Mono Amp is designed to give the best of tube amp performance at a price
previously not possible. To ensure this performance these instructions should be followed
closely.
THE 8417G MONO AMPLIFIER
OPERATING INSTRUCTIONS

4. Unplug bias meter.
CAUTION: Do Not Connect Bias Meter With Music Playing.
CAUTION: Bias Higher Than 125 ma May Damage Output Tubes.
1. Locate bias jack and bias control between transformers,
toward Input-output side of amp.
2. Insert bias meter plug into biassocket. (Generally it's easiestto
push bias meter plug into jack just far enough to get areading).
Remember, the tubes are hot.
3. Turn bias control slowly with ascrew driver until reading is be-
tween 100and 110milliamperes when amp iscold or between
115 and 125 milliamperes after amp has been on 20 minutes
or more.
BIAS INSTRUCTIONS
The mono amp has nosound-degrading protection circuitry, sothe
linefusevalue Ischosen closetothe minimum valuethatwill work. A
fuse can blow during normal use every now and then.
Ifafuse blows, Insertanew3amp slo-blo fuse and check the bias. If
the bias returns to normal shortly then there Is no damage to the
8417 tubes. If It Is more than 20 or 30 ma different than before, an
8417tube isdamaged. Turnthe amp off until thesetubes havebeen
replaced and cause has been corrected.
Damage to the 8417 tubes Is caused by:
a shorted speaker or speaker wire
large mismatch between speaker and amp impedances
constant hard clipping or overdriving
excessive bias setting
an unstable preamp (bewareof modified preamps)
If you need assistance, contact Quicksilver Audio 209-477-6428.
FUSE BLOWING

Voltage Chart
=/- 5%
Voltages measured to ground
Pin 12AX7 Pin 12BH7 Pin 8417 Pin 5AR4
10 1 310 10 1 0
2 0 2 150 20 2 465
3 0 3 158 3465 3 0
4 6.6AC(3.3)* 4 6.6AC(3.3)* 4 465 4 345AC
56.6AC(3.3)* 5 6.6AC(3.3)* 5-25App** 5 0
6150 6 0 6-25App** 6 345AC
70 7 0 7 6.6(3.3)* 70
8
.9
8 0 8 o (3.3)* 8 465
9 0
9 02 to 8 = 5.2AC
*(Va/ues for units with SN 101 through 1500) **Use high impedance volt meter
-
-
-25
-
120pf
I
12AX7 562.0
12BH7 8417
470 volts
B+
2
470 volts
B+
2
23.7K .18/400
Quicksilver Audio 8417 (Philips) Mono Amplifier Schematic