I just got these three Fivre 6C5G dirt cheap at a local place and I'm pretty stoked. The two brown base ones look like what you would expect them to, but the black base one has me a little confused. Other than the different stamp, I have never seen the top section like this. I don't know what...

That's good to know. It's not really about leaving it on, rather than about those times when I just turn it on before making something to drink and get lost in my kitchen for some 20 minutes lol Still, that was an interesting thread. Thanks for sharing.

Yeah I was aware of output transformers needing a load, so I was wondering if there might be any other reason for a Crack to suffer with no output connected.

I saw a discussion come up, so I started wondering. Does leaving a Crack running with no headphones connected for prolonged amounts of time damage the amp? I'm used to leaving my headphones connected even while warming up, but never really made sure if it's the correct thing to do.

Thank you! I've been experimenting. I was also lent a pair of nos GEC L63 which I was eager to try, but unfortunately one of them is really noisy, so I'll have to wait for another pair eventually:triportsad: They're Mullard 6J5G's in an adapter made by Deyan. They're very pretty tubes. The...

I appreciate the concern. I have actually solved the issue some weeks ago (one of the resistances in the right channel path was causing the issue). I have been enjoying my amp every day since then :)

While looking at the speedball manual I noticed a difference between the layout of the ground wires for the center lug of the 9 pin socket: while in the stock Crack manual the ground wires do "center tube lug -> potentiometer ground lug -> terminal 3", the speedball has a wire going from the...

The first connector is exactly what I had in mind. Thanks, I'm off to finding one in the EU now. Your kit looks gorgeous by the way!

I'm happily listening to some recently obtained 5998's and a pair of new output caps as we speak. I'm thinking I will just go ahead and try the speedball too, and finally see for myself how it is :o2smile:

That's good to hear, honestly. I very much enjoy my Crack, but I have an assembled speedball pcb sitting on my desk ready to be soldered on, and I can feel the effects of upgraditis hitting.

I had actually thought about just saying "whatever, let's try to solder the speedball on and see if that fixes it" but stopped since it didn't sound like the brightest idea lol. Either way, I have yet to decide if I want to install the speedball, since I've heard mixed opinions about the changes...

The issue had to be most likely on the right channel, since it was the only one affected. Replacing the volume potentiometer, output caps and sockets didn't change anything, so it had to be something in between. Turns out it was that resistor.

On another note, since during this time I was also suggested to make sure to keep the headphones unplugged while turning on and off the amp, I got to thinking about something else. I don't dig the idea of inserting and extracting the headphone jack at least twice a day (and I do like to switch...

Just giving some brief positive news to close the topic: I finally managed to find the fault. It was actually the 22k ohm resistance in the right channel, that for some reason was being noisy. Replacing it completely got rid of the issue. I don't know why the issue wasn't appearing back at the...

I want to buy one so I would like to receive photos, if that is what you mean.

It is something that I had thought about too, so I made sure to test the amplifier into many different outlets. Even when plugged with no electronic decides in its area the noise has always been there. The source doesn't even matter, as the noise appears even when no RCA's are connected.

I haven't. Since I live in Italy, both the repair and the shipping costs are going to be very high compared to the price of the amplifier itself, and the idea of shipping the built amp in a box overseas does not fill me with confidence so I have been opting for locals instead. Plus, I don't know...

This is definitely something I mean to investigate, being by far the strangest thing about my situation. I had planned to bring my amp back to one of the two places yesterday, to make sure with the repairman that we were using the same gear (I only know for a fact that he was using my tubes and...

Unfortunately yes. I have spent a good number of hours going over every and each wire and connection in my kit, and after fixing a couple of sketchy looking joints everything looks orderly.

I have indeed felt the urge to open my window and throw my amp very far into the garden on multiple occasions, but I just couldn't. I have to find a fix to this, one way or the other. Even if I gave up and decided to spend my life savings on the best amplifier I could purchase, I wouldn't be...

I have not tried aluminium foil, but I have tested my amp in a house that has no wifi beacons for hundreds of meters and the noise was unchanged. I also tried placing my amp inside of a closed microwave, which should shield well, but that had no effect on the noise either.

Unfortunately, as I mentioned before, I have already tried a number of different tube combinations and cleaned each tube's contacts. I thought I might have dirty or bad connections on the octagonal socket, so I replaced that altogether. Nothing ever changed. I have also plugged it to my UPS...

I had looked into that and found contrasting opinions, but I'll stop doing that. Thanks for the advice. The noise is constant. The only moment it leaves is when I turn the amp off.

In the chance that, hopefully, someone might have an idea of what I could try, I'm going to explain my issue and what I have tried in the past months. My kit had been working perfectly fine for a couple of months, until suddenly it started having a noise issue on the right channel that with time...

Yeah, I have a 5 page long thread open since last October, and I have yet to find a solution. Even though it should be an easy amp to trouble-shoot, I have run out of ideas of things to try, other than replacing every single component in the path...