When should I bias my new DSL40c?

[noise5150]

I just got a DSL40c about a week ago and Im wondering when I should check the bias. I assume the bias drifts a little after the initial break-in period. BTW I asked Marshall and they responded "This model is biased to 35-37mV per side."

[surfnorthwest]

No real hard rule as to when. The bias is set to ensure you are getting the best performance from the tubes and amp.

I bias when ever I replace tubes or once a year.

[dukealexan]

I always check it on any new/old amp I get right away, I've found some new ones that are way off.

[noise5150]

Hey guys, I have another question about my DSL40c which I've had for a few months now. I have noticed from the beginning that Lead 2 has an odd "issue" that may or may not suggest a problem with the amp. When I switch to Lead 2, even with the gain only half way up or less, everything sounds oddly compressed and almost slightly flubby. The notes are kinda inarticulate. Its hard to explain and I dont have a mic right now for sounds clips. I am completely happy with Lead 1 and I use a boost in front via the 4CM with my HD500x so its not that I really miss using Lead 2 but I wanted to get your take on whether or not this is an issue? Other than that, the amp performs wonderfully and sound awesome.

*FYI: I replaced the stock speaker with a Veteran 30 and I still notice this issue so I dont think its a speaker issue.

[Anitoli]

Have you tried it with a different guitar? Some pickups can be so hot that they will cause weird anomalies. For example, my 6100 on channel 3 with the low comp off gets this real flubby tone ( when using guitars with high output pups). It's like the tube cant conduct anymore or excessive overdrive. Putting the low comp on or rolling the volume off the pup clears it up. It could also be a failing tube. Do you have any spare preamps tubes you could swap in there?

[noise5150]

Have you tried it with a different guitar? Some pickups can be so hot that they will cause weird anomalies. For example, my 6100 on channel 3 with the low comp off gets this real flubby tone (when using guitars with high output pups). It's like the tube cant conduct anymore or excessive overdrive. Putting the low comp on or rolling the volume off the pup clears it up. It could also be a failing tube. Do you have any spare preamps tubes you could swap in there?

Thanks for the info. I have tried it with several of my guitars and its the same thing. I actually do have a set of 4 extra pre-amp tubes that I can try, I believe they are all good. The confusing thing is that Lead 1 is very articulate and sounds awesome.

[mickeydg5]

Lead 2 not only introduces higher gain but also incorporates a cathode bypass capacitor to increase lower frequency gain as well.

Along with what Anitoli describe these circuit implementations may be flubbing or muddying things up.

Are you using any guitar modifications, pedals or other gear that modifies/EQs the signal in front of the amplifier?

[noise5150]

Are you using any guitar modifications, pedals or other gear that modifies/EQs the signal in front of the amplifier?

I have A/Bed using it via the 4CM with my HD500x and direct into the amp and its the same issue either way. Lead 1 sounds really great so Im wondering if its just the nature of lead 2?