My amp died tonight, need help fast!!

[Lord Toneking]

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Turned on my Splawn tonight at rehearsal, let it warm for a few then started playing...everything was good for about 5 mins...then I lost volume, kinda like someone was turning down the amp...then it started crackling. I looked at the tubes and two tubes were glowing blaze orange. If they were numbered 1-2-3-4 it was tubes 3 and 4
So i shut it down, took tubes 1 and 2 that werent glowing blaze orange and put them in sockets 2 and 3. I turn my amp to 50w mode and switched the impedence from 8 to 4 ohms.....turned it on again and within a few seconds the tube in socket 2 was freaking blazing orange

I'm hoping that a new set of tubes and a bias will be the cure, I have a gig Saturday and need my amp, I dont have a backup

 

[glpg80]

have you carried the amplifier recenty?

if the tubes red-plated, you can basically kiss them goodbye as they will have a life expectancy much lower than a regular tube. basically it cooks the grids wires and makes them become brittle.

might be an open socket. it was wierd 3 and 4 went together. usually its 1 tube or a set - inners/outers.

splawn doesnt give out schematics of his amplifiers... and none exist.... so theres really nothing i can look at to help you find out whats going on here.

i hope you shut the amplifier off as soon as it happened. anytime you dont have volume when playing an amplifier could really mess up an OT by not passing high currents. they can turn into eddie-currents and litterally cook the transformer wiring until something gets hot enough to short itself as well.

best thing to do is take it to a tech or someone with a variac, pull all the tubes, and check the bias circuit. i have a feeling there is a component that is deffective. but i cant say for sure if it is open or shorted or what without a schematic and/or the amp in front of me.

maybe others will pitch in here. i know olaf would know a cause of uneven A/B redplating on the poweramp section


sorry that has happened dude, usually splawn's builds are excellent quality so im thinking its component malfunction.

 

[Lord Toneking]

thanks for the reply

I thought it was wierd too how tubes 3 and 4 went like they did .

God I hope it's nothing more than bad tubes I need this amp to be working without any issues by Saturday

 

[glpg80]

dont thank me, i havent really done anything

i meant to say open component, i dont know why i said socket its getting too late.

yeah im thinking there is something in the negative bias control thats gone south/shorted. usually that can cause uneven red-plating and not so much the individual sockets themselves. another thing that can cause stuff like that to happen is solder bridges, but its not a brand new amplifier, and im sure scott can flow solder

yeah if you need it fixed asap best thing to do is start looking for a tech. if you dont have the troubleshooting skills or the ability to drain the filter capacitors off the rectifier circuit you can really cook yourself.

best of luck

-matt

 

[crwnedblasphemy]

If a tube totally goes the splawn will blow the standby fuse. That is the first line of defense....then you won't hear shit!

I have a quad of Tung Sol EL34Bs if interested...

 

[tituba]

???????
you could have had a bad tube and moved it into either the 2,3 placement and killed the good tube. but it sounds like that you have blown something on that side of the o.p. xfmr. have you replaced the p.i. tube?

 

[glpg80]

???????
you could have had a bad tube and moved it into either the 2,3 placement and killed the good tube. but it sounds like that you have blown something on that side of the o.p. xfmr. have you replaced the p.i. tube?

A: read crown's post - each tube is fused to protect from current running away to ground if the tube becomes deffective.

B: tubes are isolated from each other with independent anode/cathode supplies, usually with a shared ground to prevent noise. all class A/B "push pull" power-amplifiers rely on the phase inverter tube to unbalance the preamplifier signal 180* out of sync of one another. two tubes each, 4 total, = 360* of a full balanced output. the phase inverter is no higher in voltage than the lead or clean channel grid voltages. the anode/cathode are the only high voltage areas and this is just a common design of tube amplifiers/areas that are mostly stable.

C: if the PI tube went, he would not have any sound at all instantly, or, when he turned it on he would not hear anything. it also would-not explain the red-plating of power tubes meaning the current is running away on two unbalanced tubes, meaning of the A-B-A-B there is an issue with X-X-A-B. hense why i recommended a current runnaway to 0V (bias is negative to common ground) or a voltage fluxuation (where/how im not sure?) which can lead to the tube damage of crackling/popping that he heard being amplified through the OT and out the speakers.

edit: the tube is not the problem, its an effect of the problem.

 

[Vrad]

Tubes... get new ones. Same thing happened to my QR. It's happened on other amps before as well.

 

[DiezelMonster]

I'd love to have eddie-currents in my amps! then maybe I'd play better!

hahha


sorry I hav enothing of value to add!

C

 

[TX6Strings]

Call Splawn. REALLY helpful dudes.

 

[grooveHT]

Tubes... get new ones. Same thing happened to my QR. It's happened on other amps before as well.

couches...fuck them!

Sorry about the Splawn Tom! I guess that's the one thing we missed in our AxeFX discussion...no tube issues with digital! Btw, I have a Mesa Trem-o and a JCM 800 2203 sitting here not being used, so if your Splawn goes down like a fat chick on a ho-ho and you need an amp for the gig, let me know!

 

[Crunch Master]

Possibly one or more screen resisters went?

 

[Lord Toneking]

Scott called me back first thing this morning. Coolest guy in the world! Anyways, he flat out told me there was nothing wrong with my amp...just a bad tube/s. So I threw in an old set that I had laying around and sure enough it was all good. A buddy gave me a brand new quads of Tung Sol EL34B's so I'm gonna take it up to John tomorrow(aka John4021 here on R-T) and he's gonna bias it up for me. Scott said that it was good that I caught it before I blew a fuse but suggested that I put new fuses in it also because it may have put a strain on them

So now all I'm worried about is how these new Tung Sols sound. I really liked the Mullards that were in it

 

[grooveHT]

Scott called me back first thing this morning. Coolest guy in the world! Anyways, he flat out told me there was nothing wrong with my amp...just a bad tube/s. So I threw in an old set that I had laying around and sure enough it was all good. A buddy gave me a brand new quads of Tung Sol EL34B's so I'm gonna take it up to John tomorrow(aka John4021 here on R-T) and he's gonna bias it up for me. Scott said that it was good that I caught it before I blew a fuse but suggested that I put new fuses in it also because it may have put a strain on them

So now all I'm worried about is how these new Tung Sols sound. I really liked the Mullards that were in it

Let me guess Tom...it's going to sound like a pissed off JCM 800 I'm sure it'll smoke man!

 

[Lord Toneking]

Scott called me back first thing this morning. Coolest guy in the world! Anyways, he flat out told me there was nothing wrong with my amp...just a bad tube/s. So I threw in an old set that I had laying around and sure enough it was all good. A buddy gave me a brand new quads of Tung Sol EL34B's so I'm gonna take it up to John tomorrow(aka John4021 here on R-T) and he's gonna bias it up for me. Scott said that it was good that I caught it before I blew a fuse but suggested that I put new fuses in it also because it may have put a strain on them

So now all I'm worried about is how these new Tung Sols sound. I really liked the Mullards that were in it

Let me guess Tom...it's going to sound like a pissed off JCM 800 I'm sure it'll smoke man!

Pissed off indeed...wierd mids and all

 

[crwnedblasphemy]

I bought a quad and tried them in my quickrod....they were pretty tight. I took them out.....I have old Teslas in it, and they just sound too sweet. lol

I did like the Tung Sols on the 50 watt setting better.

 

[glpg80]

awsome news

scott's a real down to earth guy. glad it didnt do any real damage, and glad it is in fact just two tubes that went at the same time and not the amplifier

 

[John4021]

...just bring it up here,quit yer whinning and I'll fix it.."again".
(bustin yer balls bruda)

 

[Crunch Master]

Awesome news!