Want to buy a SC20H but....Effects Loop?

[hifiman]

I bought and love my ST20H but was thinking of also adding a SC20H. What concerns me are the number of comments mostly in 2020 and 2021 about volume drop ands other issues when the SC20 Effects Loop is engaged. Also read that Marshall was aware of the issue and fixing the problem under warranty. Again this was a couple years ago. Does anyone know if the SC20H issue has been corrected with later Mfg dates? I use the Effects Loop all the time and do not want to buy a head if it has a known issue. Thanks

 

[tallcoolone]

Do you reach around to the back of your amp mid song to toggle your loop on and off?

That is the only way this is an issue. The only way.

 

[PelliX]

Do you reach around to the back of your amp mid song to toggle your loop on and off?

That is the only way this is an issue. The only way.

So I thought, but there's another one - read on

Also read that Marshall was aware of the issue and fixing the problem under warranty.

Yes, I also have the service bulletin including the parts that get changed (just a couple of resistors OTOH), if you're so inclined it's really quite easy. I can gladly share the info, no problem.

Does anyone know if the SC20H issue has been corrected with later Mfg dates?

Yes, the 'loop level being lower' issue was addressed in later revisions of the board. I'd have to dig on the forum here, but I spoke to a bloke who had a 'fixed' one, new in box, no signs of post production solderwork.

I use the Effects Loop all the time and do not want to buy a head if it has a known issue.

If the volume level is your only concern, as @tallcoolone said - who cares. Set the volume as desired and go for it. Also, the volume *difference* diminishes the more you ramp up the master.

Now, there is another issue, and that's the lack of a proper buffer when using unbuffered effects - toggle a true bypass pedal in the loop and it will pop loudly in some cases. There are relatively easy fixes for this (including just using a damn buffer or buffered pedal externally ). Rack gear in the loop is practically never a problem. Put in a Fuzz Face and ... yeah, ugh.

Apart from that the loop works just fine.

 

[Calebz]

The effects loop is only switchable with the little button on the back. If you actually use the loop, there is no reason to ever disengage it, especially in a live setting.

Unless of course part of your stage show is dicking around with the rear panel of your amp in the dark in the middle of a set. In that case, I can see how the loop could give one cause for concern.

 

[LCW]

Yes, I also have the service bulletin including the parts that get changed (just a couple of resistors OTOH), if you're so inclined it's really quite easy. I can gladly share the info,

Yes please. PM if you’re not wanting to share in this thread.

 

[PelliX]

Unless of course part of your stage show is dicking around with the rear panel of your amp in the dark in the middle of a set. In that case, I can see how the loop could give one cause for concern.

Read my post; depending on what you run in the loop, there *could* be a problem. Nothing that can't be resolved by using a proper buffer though.

Yes please. PM if you’re not wanting to share in this thread.

I'm under no contractual obligations to keep this information private, so have fun.

 

[Calebz]

Read my post; depending on what you run in the loop, there *could* be a problem. Nothing that can't be resolved by using a proper buffer though.



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I'm under no contractual obligations to keep this information private, so have fun.

We posted at the same time. I was really only addressing the volume 'issue'. I'll happily leave everything beyond that to your expertise

 

[PelliX]

We posted at the same time. I was really only addressing the volume 'issue'. I'll happily leave everything beyond that to your expertise

Ah, sorry, mate! Even if it had have been chronological, I think I came over a bit blunt. All good, no offense!

 

[LCW]

Read my post; depending on what you run in the loop, there *could* be a problem. Nothing that can't be resolved by using a proper buffer though.



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I'm under no contractual obligations to keep this information private, so have fun.

Sweet thank you!!!!

 

[scozz]

I bought my SC20 in January 2019, right after they came out at NAMM. I use chorus, delay, eq pedal, all in the loop, and a looper.

I set the button on the back panel to activate the loop, and it’s been on ever since.

There’s no reason to turn it off, it’s not manufactured to be switched on and off while performing, there no footswitch, sooo.

The slight loss of volume only occurs at low volumes, by 4 or so on the master, it’s gone. For me being an at home player, it works, it’s an advantage, it’s like a little attenuation.

 

[adam183]

out of curiousity at what time in production did this issue come factory revised?
thanks

 

[Kutt]

out of curiousity at what time in production did this issue come factory revised?
thanks

As far as I've seen it was never corrected at the factory. The fix can be implemented upon request of the customer with an authorized repair center.

Or, of course, you can fix it yourself if you're so inclined.

 

[LargeBoxSmallBox]

I bought and love my ST20H but was thinking of also adding a SC20H. What concerns me are the number of comments mostly in 2020 and 2021 about volume drop ands other issues when the SC20 Effects Loop is engaged. Also read that Marshall was aware of the issue and fixing the problem under warranty. Again this was a couple years ago. Does anyone know if the SC20H issue has been corrected with later Mfg dates? I use the Effects Loop all the time and do not want to buy a head if it has a known issue. Thanks

If you're thinking of getting an SC20H, don't hesitate, forget the loop thing and just get it. You will not regret it. Great amp! Mine was excellent with the stock Marshall-branded tubes, and got even better with NOS tubes. It stands up well with my vintage Marshall amps. To me, the amp is a keeper.

 

[ByrdmanFL]

The one I just received 3 weeks ago and made in March, has no issues with volume drop when using the effects loop. It is a little more hissy, but that could be from something in the loop vs the amp.

I agree with @LargeBoxSmallBox, get one and dont look back!