Tube Amp Archive

I tried connecting the two RCA together. The amp screamed like a banshee, and gave a pretty harsh distortion when playing. Scream and distortion was still present - but faint - when the reverb pot was turned two 0. About the valvestate sound, I kinda like it for a practice amp, particularly the OD1 ...

Hello guys, long time! I wish you all a happy new year. Allthough this is not a tube amp related thing, it is still an amp thing :) I bought a broken down Marshall Valvestate 8080. It is sort of a hybrid amp with a ECC83 tube in it. I've managed to fix everything in it except the reverb. I had to re...

Hi, I tried to google but I couldn't find them... maybe I'm searching wrong.

I'm using LTSpice, since it's free.

DocZ

Anyone know where I might find some spice models for these tubes?

6X4
6V6
12AX7
12AU7

I got a bunch of new transformers off ebay, and I'm contemplating my first scratch amp build. But I want to model some stuff first to check out what works best together.

Regards,

DocZ

Thank you for your reply, that was something along the lines of what I was thinking, I'll do that. I think this was all that was wrong with it, since when I clipped the broken lead to the lug, and hooked it up to the wall everything seemed fine. I think that this may have been all that was wrong wit...

Here are some pictures.

I was thinking I could try to strip that old insulation off, and solder a bus-wire to the stub, and use some shrink-tubing or electrical tape - but I am afraid that might be unsafe, any suggestions?

Regards,

DocZ

Sorry to revive my old thread, but I finally found out what was wrong with my amp. I let it sit under my desk for a while, I had some health issues again and Christmas took most of my time so I haven't had time to work on it. I did re-measured the fuse and tested it to make sure it was not gone. I t...

Sorry to bump my old thread, but I thought I'd post it here since I allready started here. I haven't had time to work on my amp for a while, I have been busy on the road for quite some time now. Anyhow... I went over the amp again and checked all pots, switches, I even swapped all the tubes out for ...

Yes I tried to chopstick while playing, didn't give me any clues. It doesn't use a 37189, it uses an EL84. Probably been replaced in the past. To remove the tubes I have to wiggle them like you say, and when inserting them the rectifier and power tube offer the most resistance. The preamp/effect tub...

I didn't try different tubes, I guess I'll order a new pair. I thought these tubes would last a long time?

But isn't it weird that both tubes would wear out at the same time?

DocZ

Hello, after enjoying my amp since I fixed it with a lot - and I mean a lot - of great help from you guys something happened. I was practising, then suddenly the volume dropped down real low. Upon further investigating I found that turning the volume pot has no effect - other than on 0 then it cuts ...

Ok, what you are saying makes sense. It was just the idea I got at 3 am, seemed like a good idea at the time. Oh well - at least this thing is not going on the road, it will be a practice / studio amp. I hope that pop is like you say just the parts breaking in :) If it stays the way it was after I'l...

Checked the coupling caps, no leakage, I did check the bias, but I don't remember what it was, I will check it again later. If the distortion keeps away I will not do more until something else is wrong because it is a bit of a pain to disassemble. I will chopstick and check the solder joints and com...

What is wrong with my AC socket?

DocZ

One weird thing just happened, while I was playing. I wanted to know how dirty I could get it, so I cranked everything up to 10, the distortion was there, then suddenly on a hard power chord there was a pop, and then all distortion went away, suddenly it was much louder, distortion free, just creamy...