I think I killed my Splawn...

[psychodave]

About 10 yrs ago, at a gig I had no sound at sound check. But, I could barely make out the sound as I stood next to the amp. Turns out the speaker cable was out just like the OPs. I had tuned up prior and had sound when I muted with my tuner...sound guy was messing with things and pulled out my cable by mistake. But, it was weird how I could ‘hear’ the amp not attached to any speaker. Very quiet but it was there. After shutting it down, waiting 10 I fired it up and had no issues

What you're hearing it the output transformer. Its perfectly normal for it to make noise or sing.

 

[Racerxrated]

What you're hearing it the output transformer. Its perfectly normal for it to make noise or sing.

It was literally like a tiny speaker; I could hear myself playing but barely.

 

[LP Freak]

It was literally like a tiny speaker; I could hear myself playing but barely.

I think you must of been high or something ...lol

 

[Racerxrated]

I think you must of been high or something ...lol

I know it sounds 'out there' but I'd tell you to try it...except for the little fact that it puts your amp at risk.
I swear I heard it....really.....

 

[phil b]

I know it sounds 'out there' but I'd tell you to try it...except for the little fact that it puts your amp at risk.
I swear I heard it....really.....

I remember hearing something similar when I had played one of my amps without the cab plugged in. I always thought it was coming from the tubes.. this was like 15 years ago and had no idea it was the transformer.. oops! LOL

 

[John 14:6]

Thanks for the recommendations. I have been running Ruby EL34BHT tubes. Which I cannot seem to locate now...lol! I am highly embarrassed that I made such a foolish mistake.

I am guessing the tranny is fine but the power tubes may not be doing so well and maybe they were already heading south before this happened. Don't kick yourself because most of us who have been playing for years have done stuff like this before. As for new production tubes my favorite of recent years has been the Groove Tube EL34M's which try to copy the old Mullard XF2 Dual Getter power tubes. They sound fantastic in the Splawns and Marshalls I have owned and in my Friedman Small Box. They normally last for years in my amps. As Dave Friedman says "if you have tubes that sound great and they are working fine, DON'T CHAGE THEM. It just means you have some good solid working tubes in your amp." When it comes to 12AX7 preamp tubes I usually use NOS RFT's.

 

[SFW]

Just an update. Spoke with Scott. Checked the screen grid resistors and they are fine. Have a new set of tubes on order. They should be here by Saturday. I had a set of GT Mullard reissue tubes, but they are not even close to being matched. two are coming in at 40ma and two are reading 50ma. And that's as low as I can get them. I amp have to change the bias resistor to get the new tubes down to the 30ma I like to run the amp at. We'll see.

 

[CrazyNutz]

Just an update. Spoke with Scott. Checked the screen grid resistors and they are fine. Have a new set of tubes on order. They should be here by Saturday. I had a set of GT Mullard reissue tubes, but they are not even close to being matched. two are coming in at 40ma and two are reading 50ma. And that's as low as I can get them. I amp have to change the bias resistor to get the new tubes down to the 30ma I like to run the amp at. We'll see.

You could put the 50ma, and 40ma mullards in and run them for a short time to see if the amp is fine. Doubt they would red plate in a few mins of running low vol.

 

[harddriver]

Just an update. Spoke with Scott. Checked the screen grid resistors and they are fine. Have a new set of tubes on order. They should be here by Saturday. I had a set of GT Mullard reissue tubes, but they are not even close to being matched. two are coming in at 40ma and two are reading 50ma. And that's as low as I can get them. I amp have to change the bias resistor to get the new tubes down to the 30ma I like to run the amp at. We'll see.

That's good news about the screen grid resistors... Did you check your HT fuse as well?? Even if it is not blown you might want to replace it.

10 ma mismatch isn't a big deal just the two inner and two outer power tubes work together in the Class A/B push pull of the circuit so you can arrange the tubes so the mismatch is balanced with the different current draws between the 40ma and 50ma tubes.

As Cnutz suggests at least you would know if the OT is good to go and ready to go for when the new tubes come in.

 

[panhead]

So I arrived late to band practice tonight. In a hurry to get my gear up and running, I missed the connection from the speaker out to my attenuater. I started the why do I not have sound search on my pedalboard- as that is normally why signal isn’t coming though. A loose cable or something. When I still didn’t have sound I plugged straight into the amp. Nothing. Looked at the back of the amp and saw the cable dangling from the attenuater. HD a holy fuck moment and them plugged the speaker out in to the cab.

So I get full volume sound for about two minutes and then the volume drops in half. Then slowly comes back after about 30 seconds. This repeats about every two minutes. After the fourth time, I shut the amp down. So did I just fry my OT?!!?

That wouldnt have fried the ot

 

[panhead]

I will tell ya how tough tube amps are. Bass player back in day ran a SVT with a direct box to the pa. No speaker no load no nothing. I played out with this guy for 3 years like that. Crazy huh

 

[panhead]

I remembering now , then he bought a fender 400 ps svt equal and did the same thing. SVT still worked. You can run an amp off standby infinitely without a load as long as no signal is being passed through it. I left a marshall on once for two days without a load.

 

[panhead]

About 10 yrs ago, at a gig I had no sound at sound check. But, I could barely make out the sound as I stood next to the amp. Turns out the speaker cable was out just like the OPs. I had tuned up prior and had sound when I muted with my tuner...sound guy was messing with things and pulled out my cable by mistake. But, it was weird how I could ‘hear’ the amp not attached to any speaker. Very quiet but it was there. After shutting it down, waiting 10 I fired it up and had no issues

The sound was coming out of the OT

 

[SFW]

That's good news about the screen grid resistors... Did you check your HT fuse as well?? Even if it is not blown you might want to replace it.

10 ma mismatch isn't a big deal just the two inner and two outer power tubes work together in the Class A/B push pull of the circuit so you can arrange the tubes so the mismatch is balanced with the different current draws between the 40ma and 50ma tubes.

As Cnutz suggests at least you would know if the OT is good to go and ready to go for when the new tubes come in.

I ran the amp for about five minutes with these tubes just to make sure everything was working. Then I shut it off and pulled the tubes to avoid temptation... lol! I have a new set that will arrive in a couple of days. I'll get those in and get them biased up. I will be going to my local electrical parts store to get some fuses.

 

[CrazyNutz]

I ran the amp for about five minutes with these tubes just to make sure everything was working. Then I shut it off and pulled the tubes to avoid temptation... lol! I have a new set that will arrive in a couple of days. I'll get those in and get them biased up. I will be going to my local electrical parts store to get some fuses.

There you go, I bet everything is just fine. Honestly power tubes are not as robust these days so they tend to take a dump before the OT.

I bought an rm100 with modules (for next to nothing) from a guy that ran it with no load into his DAW for a week. LOL, he was convinced he blew the OT, the power tubes were cooked, you could see scorch marks inside them. I even told him it's probably just tubes, and fuses. But he insisted it was trashed. When I got it home, low and behold I popped in new tubes, and a fuses, works fantastic.

 

[japetus]

I will tell ya how tough tube amps are. Bass player back in day ran a SVT with a direct box to the pa. No speaker no load no nothing. I played out with this guy for 3 years like that. Crazy huh

Solid state amps don't require a load.

 

[panhead]

Solid state amps don't require a load.

Ampeg SVT is a 300watt tube bass head

 

[japetus]

Ampeg SVT is a 300watt tube bass head

Oh, I am used to all the SS ones lol.

 

[harddriver]

I ran the amp for about five minutes with these tubes just to make sure everything was working. Then I shut it off and pulled the tubes to avoid temptation... lol! I have a new set that will arrive in a couple of days. I'll get those in and get them biased up. I will be going to my local electrical parts store to get some fuses.

Glad to hear it, if the original HT fuse did not blow then it sounds like the tubes went first even before the HT fuse could blow.

I would still replace the HT fuse though as it probably saw some excessive current draw thru it.

 

[Devin]

It was literally like a tiny speaker; I could hear myself playing but barely.

Yeah this definitely happens; my Fender Prosonic head would do this. Sound coming out of the transformer - tripped me out too

Also I'm an asshole for ever selling that amp