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W4BD
10-09-2010, 10:00 AM
Well I am kind of confused about how to change my amp to 240V. The manual is kind of confusing to me.


The AL-811HX (export model) is wired for 240V, 50/60 Hz
operation. The appropriate plug is not provided for this model.
You must wire the proper plug on the end of the power cord
supplied. Simply cut the existing plug off and wire the
appropriate plug in its place. If the line voltage in your country
is not 240V, then you must change the transformer to the
appropriate setting indicated by the chart below. Note: the AL-
811H transformer allows operation on 100V line voltage in
countries such as Japan.
NEVER REWIRE THE POWER SUPPLY TO BOOST THE
HIGH VOLTAGE ABOVE 1800 VOLTS. ALSO, DO NOT
ATTEMPT TO REWIRE THIS AMPLIFIER WHILE IT IS
CONNECTED TO POWER.
The wiring between the fuse box and the amplifier AC outlet
must be 14 gauge or larger in order to supply the operating
current required (10 amperes) without a significant drop in the
line voltage. The outlet should be fused for the wire gauge used.
VOLTAGE BUCK BOOST PRIMARY
*120 A to 1, B TO 2 C to D, E to F
110 1 to 2, (A,B OPEN) C to D, E to F
100 A to 2, B to 1 C to D, E to F
For 240, 230, 220 all three primary conditions apply ↓
**240 A to 1, B to 2 no connection C to D
230 1 to 2, (A,B OPEN) D to E
220 A to 2, B to 1 no connection E to F

Now it looks to me like I have to cut "CtoD" jumper but the start of the instructions say "Simply cut the 120V plug off and wire on a 240V plug" so which is the proper way to change it? I don't want to "Let the SMOKE OUT". There is a sort of diagram that will not copy and paste for strange reason.

KC2UGV
10-09-2010, 11:59 AM
You most likely have to do both. Because the transformer is stepping up 120 to whatever it needs. By wiring just the plug, and not the transformer, you would double all voltages after the power supply circuits, and let out the smoke.

Caveat being, I've never done this operation before for this piece of equipment, however, it would follow, as I've seen similar instructions for other rigs.

K6BSO
10-09-2010, 12:22 PM
DO NOT ATTEMPT TO REWIRE THIS AMPLIFIER WHILE IT IS CONNECTED TO POWER.

"Okay, important safety tip. Thanks, Egon."

http://upload.wikimedia.org/wikipedia/en/4/4f/Egon_GB1.jpg

W4BD
10-09-2010, 02:12 PM
Carl

Well I am crazy as hell but I ain't STUPID. I guess there are fools out there that would try to change it over with out unplugging it.

I am still reading the reflections you sent me.

K6BSO
10-09-2010, 02:46 PM
Well I am crazy as hell but I ain't STUPID. I guess there are fools out there that would try to change it over with out unplugging it.

Sadly, you are probably correct.


I am still reading the reflections you sent me.

Not exactly gripping reading, eh? But very educational. I probably should read it again myself.

KA5PIU
10-09-2010, 06:34 PM
Hello.

Read that again.

First, you cut off the plug if it is not the correct one for your country.

Second, if the voltage is not 220,,,do the transformer tap changes.

This is a 1, and perhaps 2 step change.

W4BD
10-23-2010, 10:30 AM
Well I got the time this morning to change the 811H over to 240V. I measured the voltage and I have 246V no load on the outlet. I unplugged the amp so I wouldn't let the SMOKE out of ME and wired the 240 plug white and black are the 2 hot leads and green is ground. I pulled the cover off the back and cut the wire from C to D and put cover back on. While I was at it I wired in another 240 receptacle so I can plug 2 amps in at the same time but only run 1. Plugged the 811H in and turned it on in Standby and after about 1-2 seconds it blew both fuses in the AMP. Anybody got any ideas as to where the problem can be. The directions are about as clear as mud on changing the voltage at least to me. I will get a couple more fuses and see if anybody can point me in the right direction.

KG4CGC
10-23-2010, 03:04 PM
http://www.nojolt.com/Understanding_240_volt_circuits.shtml

May or may not help. If you've wired the outlet correctly, double check your amp wiring and check the fuse ratings.
Please don't take my word for this as I am no expert on the amp.

W4BD
10-23-2010, 03:46 PM
Well if you look real close at the text it shows a tiny little arrow pointing down and the statement "ALL THREE PRIMARY CONDITIONS APPLY". For 240, 230, 220 all three primary conditions apply ↓
**240 A to 1, B to 2 no connection C to D
230 1 to 2, (A,B OPEN) D to E
220 A to 2, B to 1 no connection E to F. I went in and I had already cut C to D and I added D to E and cut E to F. Put new fuses in and plugged it in and turned it on and I have 1800V HV now where I had 1750 or so. I was getting about a 10:1 amp factor or 10W drive and 100W out and the light would kind of dim when I would key the amp so I will play around later on tonight and see if I still get dimming of the lights.