Amp suddenly sounds muddy

[Blaoskaak]

OK. Well I did mention early in the thread to check your cables too

Yes i did. None of the cable are bad.

Nice overtones !

Thanks! just practiced hybrid picking. Just started playing guitar for 4 months now.

What do you guys think when you hear the fragment?

 

[Troy T. Blues]

Yes i did. None of the cable are bad.



Thanks! just practiced hybrid picking. Just started playing guitar for 4 months now.

What do you guys think when you hear the fragment?

Oh! Sorry about that. OK, I haven't been able to listen to the clip yet. So, we still haven't figured out the issue?

 

[Blaoskaak]

Oh! Sorry about that. OK, I haven't been able to listen to the clip yet. So, we still haven't figured out the issue?

I thought you meant that i played the fragment bad. With alot of notes that aren't supposed to ne there. Lol. What you mean with overtones then?

No, havent found the problem. I also didn't replace the tubes, because the guy in the music store says they are good. Based on that they are glowing and playing radio over the amp.

I just checked all my cable's on continuity. They are all fine. So is the continuity from input jack on guitar to al pots.

Can tubes be broken, but flow anyway? And my amp gets warm. (Not hot) is this also normal?

 

[Troy T. Blues]

I thought you meant that i played the fragment bad. With alot of notes that aren't supposed to ne there. Lol. What you mean with overtones then?

No, havent found the problem. I also didn't replace the tubes, because the guy in the music store says they are good. Based on that they are glowing and playing radio over the amp.

I just checked all my cable's on continuity. They are all fine. So is the continuity from input jack on guitar to al pots.

Can tubes be broken, but flow anyway? And my amp gets warm. (Not hot) is this also normal?

A tube that is not warm and the others are? Either way, I would buy a 12AX7/ECC83 and follow what I said in the beginning. If it's not a tube, it's still a good idea to have a spare or two around. I'll listen to the clip later when I can.

 

[Blaoskaak]

A tube that is not warm and the others are? Either way, I would buy a 12AX7/ECC83 and follow what I said in the beginning. If it's not a tube, it's still a good idea to have a spare or two around. I'll listen to the clip later when I can.

They are probably warm. If i touch the amp it is warm. Tommorow i buy a different pre amp. Should i replace both?

He also said if i replace my tube i have to adjust something on the PCB

 

[Troy T. Blues]

They are probably warm. If i touch the amp it is warm. Tommorow i buy a different pre amp. Should i replace both?

He also said if i replace my tube i have to adjust something on the PCB

Start only with the 12AX7's/ECC83. Those you can swap out with ease. The EL34's are the power tubes. I'm assuming those are fine, don't mess with them. If you change EL34's, you'll need to bias the amp - If you don't know how to bias an amp, don't try it! Dangerous!

 

[Blaoskaak]

Start only with the 12AX7's/ECC83. Those you can swap out with ease. The EL34's are the power tubes. I'm assuming those are fine, don't mess with them. If you change EL34's, you'll need to bias the amp - If you don't know how to bias an amp, don't try it! Dangerous!

Oké. Got it! I don't know, so i leave it as it is. Thanks and you'll hear from me

 

[Iron1]

Have you tried a different guitar? If a professional tech told you the tubes were good/amp was good, you swap cables and no change, that leaves the guitar... Not usually a source of problems, but you never know.

 

[Trelwheen]

You should've played a guitar through the amp while at the music store so the tech could hear what you are experiencing.

Ecc83/12AX7 are preamp tubes. No re biasing is needed when changing these tubes.

EL34 are power tubes. The amp must be re-biased when these are changed.

I would do this:

Purchase a new ecc83/12AX7 tube.

Replace one 12AX7 in the amp with the new one. Now play your guitar through the amp. If it still sounds muddy, pull the new tube out and put the old tube back in. Now replace the next 12AX7 with the new one. Play your guitar through the amp again. Repeat until you either find the bad tube or have gone through all three preamp tubes.

Replace the tubes one by one as I described.
If you just indiscriminately replace all the tubes you will not know which one of the tubes is bad.

If swapping out the preamp tubes does not fix the problem then you need to take it back to the tech and have him play an actual instrument through it

 

[jo_gel]

I thought that the SV20 was fixed bias or something like that no?

 

[Blaoskaak]

Have you tried a different guitar? If a professional tech told you the tubes were good/amp was good, you swap cables and no change, that leaves the guitar... Not usually a source of problems, but you never know.

You should've played a guitar through the amp while at the music store so the tech could hear what you are experiencing.

Ecc83/12AX7 are preamp tubes. No re biasing is needed when changing these tubes.

EL34 are power tubes. The amp must be re-biased when these are changed.

I would do this:

Purchase a new ecc83/12AX7 tube.

Replace one 12AX7 in the amp with the new one. Now play your guitar through the amp. If it still sounds muddy, pull the new tube out and put the old tube back in. Now replace the next 12AX7 with the new one. Play your guitar through the amp again. Repeat until you either find the bad tube or have gone through all three preamp tubes.

Replace the tubes one by one as I described.
If you just indiscriminately replace all the tubes you will not know which one of the tubes is bad.

If swapping out the preamp tubes does not fix the problem then you need to take it back to the tech and have him play an actual instrument through it

Got 2 new pre-tubes in there and the problem still remains. Start doubting if it's not my guitar. yesterday I tested the continuity of my jacket to all potmeters and that's good.

On my input jack are 2 cables soldered. one white and one without jacket (ground?) if I check the continuity to the white cable then I have no continuity, the other cable does. What else can I test?

Have an appointment tomorrow at the music store, to play with a guitar from them over my amplifier. I will also take my guitar with me.
My other guitar I don't have pickups

in yet. these will probably be delivered tomorrow.

 

[Iron1]

Got 2 new pre-tubes in there and the problem still remains. Start doubting if it's not my guitar. yesterday I tested the continuity of my jacket to all potmeters and that's good.

On my input jack are 2 cables soldered. one white and one without jacket (ground?) if I check the continuity to the white cable then I have no continuity, the other cable does. What else can I test?

Have an appointment tomorrow at the music store, to play with a guitar from them over my amplifier. I will also take my guitar with me.
My other guitar I don't have pickups

in yet. these will probably be delivered tomorrow.

So weird. Hope ya get it figured out quickly.

 

[scozz]

I thought that the SV20 was fixed bias or something like that no?

The Sv20 and the Sc20 are cathode bias,...which means you can change the power tubes without biasing. There's no bias pot on the amp to do that anyway, sooo,...no biasing required.

I don't know if it's necessary @Blaoskaak, but when I purchased new power tubes for my Sc20, I ordered a "matched set".

As far as the audio clip you provided, It doesn't sound muddy to me. I'll go back and give another listen though.

 

[scozz]

I gave it another listen and it really doesn't sound all that muddy to me. Are your settings the same as they've always been? It sounds to me as if the eq section could improve what you're hearing.

 

[Troy T. Blues]

The Sv20 and the Sc20 are cathode bias,...which means you can change the power tubes without biasing. There's no bias pot on the amp to do that anyway, sooo,...no biasing required.

Oh OK, I sort of lost sight of that for that amp along the way. Thanks for the clarification.

 

[Jethro Rocker]

If the cable is bad it won't sound muddy it will cut out and maybe come back in with some static etc. Or stop completely.

 

[jo_gel]

The Sv20 and the Sc20 are cathode bias,...which means you can change the power tubes without biasing. There's no bias pot on the amp to do that anyway, sooo,...no biasing required.

I don't know if it's necessary @Blaoskaak, but when I purchased new power tubes for my Sc20, I ordered a "matched set".

As far as the audio clip you provided, It doesn't sound muddy to me. I'll go back and give another listen though.

Thank you very much for confirming this. Cheers!

 

[Blaoskaak]

The problem was a loose contact from the jack input in the amp. Thanks all for the help!

 

[Mitchell Pearrow]

The problem was a loose contact from the jack input in the amp. Thanks all for the help!

Glad you got it all squared away brother, but you where given awesome advice by my buddies here on the forum for future, tube issues that will pop up from time to time.
Cheers
Mitch

 

[Troy T. Blues]

The problem was a loose contact from the jack input in the amp. Thanks all for the help!

Glad you got it figured out. Honestly, I would've never guessed that.