Here is an early picture of the internals of minimus' rebuilt Extreme.   Some of the wiring had to be shortened and rerouted.   Bypass caps were added to the output coupling caps.   The signal wiring was changed a bit.   This should give you an idea of what had to be done to...

Quote: -The transformers on all stock Extremes or all SinglePower Extremes appear to require replacement. This is not horribly expensive ($175-$300, installed depending on the transformer and hourly labor cost). The first part of this statement is absolutely true. The transformers on...

Here is a nice, fuzzy shot of a completely rebuilt Extreme. This unit was pretty much stripped to the chassis. The RCA input connectors, AC inlet, AC switch, volume control, LED and headphone connector are just about the only things left from the stock unit. The transformer was...

The 120 volt versions usually used Hammond transformers. There is a 120/240 series of Hammond transformers, that is probably what was used. What matters is what the filament current spec is. A fairly easy way to determine if your transformer is undersized is to measure the filament voltage...

Use as high current a diode as you can fit. The biggest problem will be to get rid of the heat generated by the current passing through the diodes. Something like a large bridge rectifier bolted to the back of the chassis may work best to radiate away the heat. This will not help if the...

Quote: Originally Posted by fongalv I understand the issues of the need for the bleeder resistors across the caps and the underspeced voltage switch(which would be more tricky to mod), but since I'm not touching the large caps all the time, and neither am I fiddling with the voltage...

I just finished looking at a MPX3. This one has the high/low voltage switch that is rated at 25 volts. No balancing resistors. Black Gates on the HV section. A couple of Russian Teflon caps and this: An under $30.00 power transformer. This amp was running a pair of 6BL7GTAs for outputs...

Here are some shots of the latest Extreme to visit me. First is the standard overheated transformer. In this amp's case, it led to failure of the capacitor in the filament circuit. In other words, the cap puked it guts out. Here is the bottom of the case with more cap puke...

Your amp is in fairly poor shape with all the overheated parts. The high voltage circuit should be removed. It does not improve the sound when running the output tubes at high voltage. If anything, it degrades the performance. The switch is rated 25 volts. It is likely to fail at any time...

Sorry to be the bearer of bad news, but the Plitron transformers used in the Singlepower Extreme Platinum are wired up the same way as the Hammond transformers discussed in the first post in this thread. The dual primary taps, which are supposed to be run in parallel for 120 V and series for...

Here are some photos of a Platinum Extreme sent to me. This one was built on a MPX board. The light blue cap in the middle is the smoothing cap for the filament supply. Does it look like it may have been under some stress? BTW, filament voltage was measured at 4.0. Other side...

Thank for your comments, Skylab. I just spoke to the owner of the Extreme after he saw the photos. He actually likes the look. Kinda like the Donald North amps with their bright blue chassis. Beauty is in the eye of the beholder The bridge rectifier for the filaments is bolted the the...

Here is the Edcor transformer mounted on a small chassis Extreme Same amp with transformer cover placed over the Edcor. This amp also had the HV diodes replaced and film caps added to the output caps.

PhilS Supra has been repaired/updated/made safe. Here is his picture of the unit. 100K 2 watt resistors were placed across the juice can caps. The rectifier diodes for both high voltage and filaments were replaced with HexFREDs. The transformer wiring through the chassis had additional...

Nice job, Miguel. The diodes directly under the power switch look like they have been getting warm. The circuit board is discolored under them. I suggest you may want to check their rating and maybe replace them with higher current and voltage HexFREDs. Two 6BL7 want 3 amps. Add in the...