Studio Pre-amp Clean Channel Distorting

[mojosteve]

I have an old Mesa Studio preamp which had the channel 2 c+ mod which is fantastic! However, channel 1 wont stay clean. I've tried every comination with the settings even had the master and gain almost off, changed valves even had a tech replace the LDR's which other users suggest on this forum. If anyone has any other ideas they would be greatly appreciated!!?

Cheers
Steve

 

[talltxguy]

1) What kind of pickups are you using on the clean channel?

2) What kind of power amp are you running and what kind of effects while on the clean?

3) What's the cab that you're running into?

 

[mojosteve]

Hey, I'm using an mxr carbon copy delay and a boss chorus in the loop with the loop level set to low. Running the preamp into the fx loop of my stiletto head and play that through a fender supersonic 8ohm cab with v30's. The longer I leave the preamp on the more distorted the clean channel gets! I also had the valves checked and replaced a couple, I,m using a comination of single coils and humbuckers and still getting the same results. Really stuck with this one!!

 

[talltxguy]

So you're using the FX loop return jack on your Stiletto...right...meaning that you're not plugging into the Stiletto and using the FX send & return of your Stiletto?

I assume you're plugging directly into the SP input jack. Have you tried going out of the main output as well as the recording outputs of the SP? Are both outputs unable to stay clean?

I'm also wondering if the SOLO control on the Stiletto is boosting that SP clean signal?

 

[mojosteve]

Yeah the main output of the preamp is going into the return of the stilleto. Weird thing happened today, the clean worked fine for 20 mins then went all mudy and toneless the gain channel sounded different too, wonder if I've still got a duff valve in there.

 

[talltxguy]

Dang man, you got me! If it was working fine for 20 mins, then it's not gonna be anything I thought. Sounds like you've got your connections hooked up properly. The master volume and volume were set well enough since you were getting a good clean tone.

Something has got to be heating up and causing that distortion? Wish I knew more and could help. Somebody else with more experience will chime in soon. I hope it's only a valve though. Let us know.

Anyway, how is that SP sounding through the Stiletto power amp?! Do you prefer the cleans using tube rectifier or solid state?

 

[mojosteve]

Hey, thanks for the help man, this preamp has me completely stuck too! When its working good its the best tone I've had and sounds good through the Stiletto, looking forward to the day I pick up a Boogie poweramp! I keep everything on the diods just to get as much head room as possible. The Stiletto really does love pedals I put a Suhr Riot in the clean sounds great.