I believe I have an issue with one of the PS2 units I own. Ive been using it with a 100w Super Lead for the past couple years and haven’t had any issues with this particular unit (I own 2) till now.
As I was recording in silent mode the signal started dipping a lot, then suddenly went very loud. This was followed by a Valve blowing in the Super Lead along with the HT fuse being taken out pretty violently. I got the Super Lead sorted and it returned today, assuming the changes in volume were just down to it being about to give out. I’m aware valves have a finite life span so it seemed normal, although rather annoying.
I plugged things back in and something immediately wasn’t right. It was much louder than it should be, sounding as if the actual signal going into the load section was clipping. There were a few weird dips as well just like it was before the amp blew previously. This is all in silent mode.
Long story short, after a process of elimination, I tried running the exact same signal route with the same cables through my other PS-2 unit and everything was fine. I went back to the unit in question and the signal was not. I’ve recorded a sample of each so you can hear the normal sounding one and the other. It clips at the start followed by a big drop at the end. Please see follow this link to both the examples on Soundcloud: Stream George Twydell | Listen to amp playlist online for free on SoundCloud
Do you guys have any idea what this would be? Please also note I always have the unit on for the fan when using it with the 100w.
Just want to check a few things. I’m make sure the FX loops is unplugged and the level switches in the front panel are the same as well as the reactive load toggle switches.
If this is the case, then I think you have eliminated and differences. So just changing power stations is the only difference?
Yes I tried without the FX loop, running through my 4x12 and had the same strange clipping and volume blips. All switches and settings the same when comparing on both units. The unit itself made the difference.
Also worth mentioning using it as a power amp works fine still. I have a UA FX Lion pedal that I can use through it. It’s just using the real amp which is causing the issue.
I could listen to the clips. Yes I can hear the volume drop out.
Do you have a multimeter that can measure resistance? If not, I’d suggest sending it back for a service. The only thing I can think of is that there is an issue with the reactive load. If you do have a multimeter, with the power station off, disconnect everything. Then plug in a speaker cable to the Amp In and measure the DC resistance between the tip and shell at the other end of the cable.
I tested with a multimeter and it wasn’t giving me any reading back. Seems like the load section is indeed buggered
I bought the unit from Guitar Guitar a couple of years ago and their website says they have a 3 year warranty so I’ll contact them tomorrow.
If for whatever reason they can’t do anything it would be much appreciated knowing the closest recommend Fryette servicer to me, around Reading, Berkshire.
Hey dude I managed to get it in contact with Guitar Guitar and it was indeed still under warranty with the them.
I’m gonna see if they will sort the other problem out too but after this problem is sorted. Still need at least one with me so I can use the power section for in the meantime…
Without knowing exactly what resistors, it’s hard to say. Power resistors are also used in the valve biasing circuits. But yes, the big metal ones are in the load.
As it seemed to be an issue before the amp side of things on the power station I think was indeed referring to the power resistors in the load section. The recordings were made using DI. Would these blowing cause there to effectively be no load for the amp anymore?
I have had one of these resistors fail in a project of mine before. It failed open, and that makes sense if there is a break in the wire somewhere internally. The reactive load has a few of these, so probably the impedance curve was modified but probably not drastically.
I suppose the thing I’m a little worried about is my 1959 cooking it (I know I mentioned it before) it does get very hot… I aways have the fan on it though.
Unless you are overdriving the power stage of the amp so much that you are making a square wave (fuzz) for hours, don’t worry about it. Clean signal is going to be around 100W maybe a bit more. But then as the power stage distorts, it does not increase the voltage or current (instantaneous electrical power); that remains the same. What happens is that the waveform clips more and more so the area under the curve increases, so more power gets dumped into the load. This is called crest factor.
it does get very hot… I aways have the fan on it though.