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Author Topic: Soldano sp77 earth problem? also how do you dial your poweramp  (Read 34770 times)

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gb

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Hi guys

I know this is not ada gear. I do have a non ada gear problem not sure if anyone can help me troubleshoot.

I have a soldano sp77 which i love and i alternate between this and my ada mp1 (Mp2 was awesome but just not for me so its on the back burner for now .. possibly for sale later not sure. i dont want to regret selling lol) .. anyway!

so at rehearsals i started having some crackling noise come through then i noticed tapping my foot on the guitar lead you could hear it through the amp/speakers. but the crackling was evident with or without the tapping. I thought it was tubes and replaced with new tubes but it still randomly crackles and noticeably. Wondering an earth problem? the sp77 is fairly mint in condition and well looked after. not sure is there anything i can do to test anything? or does this sound like a common "problem" with a common "cause" ?

Granted i thought it was leads etc. but i plugged it all in using same guitar into the ADA MP1 and it was fine.

Which leads me onto my next question. prior to all this i was having volume issues cutting through the band mix live. What i was doing (still new to racks) ada mp1 or soldano sp77 into the 2902 .. 2902 volume was at level 4 or 5 (10-11 oclock) and i was cranking the output on the ada mp1/soldano sp77 to get volume .. which my experienced mate said was incorrect. This way im pushing the preamp to get volume which is not correct. He said i should crank the volume on the 2902 (experiment where the sweet spot is) but somewhere between 2-3 oclock - max. and find a sweet spot .. then use the output of the preamp to manage volume. well WOW! boy he was right .. i was in tonal heaven and really blowing everyone away and i was back in the game .. he did mention, depending where dials were at that i should only have the output of the preamp a few notches up and sounding brutal but sweet.. my cleans are now also awesome doing it this way. I really found this sweet spot it was amazing.

I was just wondering if others do it this way or if this is common practice and i was just doing it wrong intially.

Anyway open for discussion and assistance on both queries... lol all i want is that lynch wicked sensation or ratt skid row poison sound or close to it as most of the music i play or like sounds like *sigh*

Cheers
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gb

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dammit.. just played with the mp2 again .. loving it still
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rnolan

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Hey gb, if you do decide to sell your MP2 I'm interested and it would go to a good home  ;)
Trouble shoot.. those symptoms sound like connector problems (jack sockets, leads), if you haven't changed your guitar jack socket out in a while it's allways a good idea, they take lots of ware and tear. Don't skimp, put in the best quality you can, this is the first fundamental connection in the chain and they do wear out..
Confusing, no problem with MP1 but is with sp77 ?? could be that the connection issue is intermittent ? or issues with sp77 (possibly input jack needs a clean with contact cleaner, can't hurt BTW and basic maintenance). So that's the common stuff..  Could be an issue in the sp77 as crackling is random (could be just the fridge turning on off in the power circuit (solution power conditioner or uncoupled UPS)).  Check leads power board(s) etc
I've got 3 power amp vol setting opinions/experience.
In a PA setting (as I'm an audio eng), you'd normally turn all power amps up full, gives best headroom and control overall vol from desk (good gain structure)
In PA gear where you want to over power the speakers (i.e. you have more power amp available than speakers can handle e.g 500 w amp > 300w speaker), valid scenario, even better head room, turn amp to 3/4 ish, carefull can blow speakers..
For guitar rack setups, I tend to go between 1/2 to 3/4 on power amp and around 1/2 or a bit more on MP1/2.  From a gain structure context, I wouldn't go less than 1/2 on power amp, and adjust MP1/2 input to suite overall vol.  However, if you've got other stuff chained between MP1/2 > power amp, it will change everything as now you have to get  the gain and the wet/dry mix right through each of them.  Anyway give me a call anytime we can chat at length
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gb

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Hey gb, if you do decide to sell your MP2 I'm interested and it would go to a good home  ;)
Trouble shoot.. those symptoms sound like connector problems (jack sockets, leads), if you haven't changed your guitar jack socket out in a while it's allways a good idea, they take lots of ware and tear. Don't skimp, put in the best quality you can, this is the first fundamental connection in the chain and they do wear out..
Confusing, no problem with MP1 but is with sp77 ?? could be that the connection issue is intermittent ? or issues with sp77 (possibly input jack needs a clean with contact cleaner, can't hurt BTW and basic maintenance). So that's the common stuff..  Could be an issue in the sp77 as crackling is random (could be just the fridge turning on off in the power circuit (solution power conditioner or uncoupled UPS)).  Check leads power board(s) etc
I've got 3 power amp vol setting opinions/experience.
In a PA setting (as I'm an audio eng), you'd normally turn all power amps up full, gives best headroom and control overall vol from desk (good gain structure)
In PA gear where you want to over power the speakers (i.e. you have more power amp available than speakers can handle e.g 500 w amp > 300w speaker), valid scenario, even better head room, turn amp to 3/4 ish, carefull can blow speakers..
For guitar rack setups, I tend to go between 1/2 to 3/4 on power amp and around 1/2 or a bit more on MP1/2.  From a gain structure context, I wouldn't go less than 1/2 on power amp, and adjust MP1/2 input to suite overall vol.  However, if you've got other stuff chained between MP1/2 > power amp, it will change everything as now you have to get  the gain and the wet/dry mix right through each of them.  Anyway give me a call anytime we can chat at length

cheers mate.. i think i might do. I dont want to let this beat me and i want to learn!! I want that versatility with the rack setup. I have the replifex which yes im not sure if im doing the correct levels etc. specially with all the options within the replifex lol.

Yes definately isolated to the SP77 everything else in the chain (leads, guitar etc..) is fine .. only when the sp77 is connected to the poweramp.. even with no guitar lead or input.. just output to amp..nothing looks blown inside (like capacitors or resistors). I jiggled the output jack to see if i can force the noise.. but nothing.. as in no pattern. It just randomly starts marking scratchy noises the tube sockets look visually fine but some of the contacts look tarnished and some look bright .. maybe thats where the issue is. ?

I put 2 new mullard 12ax7s in v1 and v2 .. i left v3 and v4 empty an theres no noise but no output either .. when i put tubes in v3 and v4 thats when it starts making noise.. not sure if that means anything as i dont know how all 4 tubes interact

i noticed it makes this scratch noise when i also tap the preamp itself and give it a little "smack" or if i tap the case its sitting on it makes the noise and amplifies out to speakers. Ive tried several different tubes. It sounds to be tube related although im using new tubes and tried different ones. so not sure. theres really not alot inside this thing a few resistors and capacitors and thats it lol.
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rnolan

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What it sounds like (as long as all the components in t sp77 are still good ?? ), is maybe dry joints, you can re-flow the circuit board (re-melt each solder join), if it's still in warranty though ?? take it back
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gb

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What it sounds like (as long as all the components in t sp77 are still good ?? ), is maybe dry joints, you can re-flow the circuit board (re-melt each solder join), if it's still in warranty though ?? take it back

oh not under warranty lol. for now ive put the sp77 aside and gunna try my mp1 or mp2 again for that 80s hair metal sound. i think i need to get alot into the effects side too (replifex) as i think thats the key aswell to that big sound (reverb and delay?)
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rnolan

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Hey gb, go for it  :thumb-up: I know I keep it on about it but it's important to ensure the signal from your MP1/2 gets to the power amp as analogue, i.e. don't chain it through a digital device (you need to mix in the digital effects and preferably not within the digital unit unless the unit has a true analogue dry pass through, rare BTW), the difference is quite astounding, the A/D D/A convertors in the majority of digital units (and sounds cards) are very ordinary/stuff your sound.  You can do this with the MP2 loop coz it's parallel (so mixes in the loop to analogue signal), not so easy with MP1 as its loop is serial, putting in a digital device with no true analogue pass through will stuff your sound (may as well buy a line 6...)
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MarshallJMP

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Usually this comes down too 2 problem,either the tubes or a bad solder joint.You replaced the tubes os we can pretty much rules that out.So the only thing left is bad solder joint.So best is to reflow al the joints.(like rnolan already said).I would start with the power supply.
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gb

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I thought I replied to this but looks like it didn't work.

What do you mean by reflow?  Heatup the solder and let cool?.

Also hers a lic of my tube sockets. Some pins look darker than others. .is it possible ths could be an issues with the socket

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gb

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A month ago I put a 15k resistor parallel to one on the board as a popular gain boost mod. I had trouble getting the resistor soldered on top. It was fine for a few weeks but  wonder if this could be causing random scratchyness. I removed the resistor but the problem is still evident. Could I have done damage to the existing resistor from the constant heating up of solder to make it stick.?
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MarshallJMP

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It could be the sockets but i really doubt it.As for the mod,no don't think so.Another possible cause is that one of the anode resistors is bad,this can also cause this problem,but to find this you will need to replace them all.
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gb

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After some playing with it ast night. I can replicate the issue by moving or jiggling the V1 tube. And I can stop it depending where its positioned. After chatting to rnolan last night  perhaps its the contacts on the socket. Ill try contact cleaner first to see if this helps but also inspect to see if the socket is grabbing the lins properly. I recall this also started happening when I removed the original tubes to try new ones (just cauae the other tubes were very old)
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MarshallJMP

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You could also try to resolder the contacts of the tube socket.
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gb

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You could also try to resolder the contacts of the tube socket.

Thats a good idea. I will try that. Thanks! !
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MarshallJMP

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Normally you should be able to see cracked solder joints.
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