Do I need an effects loop buffer? Slight volume loss

[dan the man]

I'm getting a slight volume loss when engaging the effects loop in my amp (marshall dsl100hr). I don't think it's the amp, because if I active the effects loop with no cables attached to the send and return, things sound fine.

However, if I plug in at least one pedal to the loop, the volume loss occurs, even if the pedal is off. I've tried with a few pedals to make sure it just wasn't a faulty pedal.

I am using (temporarily) a shitty one-spot power supply for my pedals, but I don't think that's the issue, although I guess it could be.

I do have fairly long cables, about 25' I think, but they're top notch (mogami gold).

I don't have this issue when I'm using my other pedalboard that has the Boss ES-8, I think the Boss might be buffering each of these pedals, or maybe I didn't notice the difference because the loop is always on with that setup.

I'm going to troubleshoot some more, and try with my 6505 to see if the same issue occurs, but I know there's some slight differences in most amps when the loop is activated. My understanding is that the loop adds a circuit that slightly affects the tone.

I'm wondering if I need some sort of buffer for the effects loop.

Here's my pedal setup that I'm trying to run, in case it helps. (The top set is running through the loop and the bottom are running in front. The AMT P2 is bypassed and just there for a gigging backup plan in case I have to use someone else's amp)

 

[Demiurge]

Before bringing another piece of gear into the equation, you could throw a couple pedals in the loop powered by batteries and with shorter cables just to see what happens. The One-Spot has only given me ground loop problems but who knows; regarding the cable, I don't know if quality mitigates the tone-suck that supposedly happens at longer lengths.

 

[dan the man]

Before bringing another piece of gear into the equation, you could throw a couple pedals in the loop powered by batteries and with shorter cables just to see what happens. The One-Spot has only given me ground loop problems but who knows; regarding the cable, I don't know if quality mitigates the tone-suck that supposedly happens at longer lengths.

Good call, I will try with batteries and shorter cables. Definitely worth a shot

 

[Emperoff]

I've found this issue in some amps. Whenever you plug something into the FX loop, the overall volume goes down. Since none of your pedals have a level control, I'd say get yourself an EQ pedal as the perfect excuse.

 

[dan the man]

I've found this issue in some amps. Whenever you plug something into the FX loop, the overall volume goes down. Since none of your pedals have a level control, I'd say get yourself an EQ pedal as the perfect excuse.

Yeah, I was thinking worst case scenario, I could just pop a clean boost in there to compensate. But I know some guys have buffers (same thing?) for longer cable runs and /or lots of pedals.

 

[Kosthrash]

Yeah, I was thinking worst case scenario, I could just pop a clean boost in there to compensate. But I know some guys have buffers (same thing?) for longer cable runs and /or lots of pedals.

Try to use a buffer before the rest of the pedals within the fx loop and you'll most probably solve the issue 😉
Also check the manual that your pedals can work properly with line level signal coming from the fx send from your amp.

 

[dan the man]

Also check the manual that your pedals can work properly with line level signal coming from the fx send from your amp.

Oh good call, I didn't think about this

 

[Emperoff]

Yeah, I was thinking worst case scenario, I could just pop a clean boost in there to compensate. But I know some guys have buffers (same thing?) for longer cable runs and /or lots of pedals.

A buffer is not the same thing as an EQ (although an EQ can have a buffer). The EQ also, well, acts as an equalizer

And BTW, I see three Boss pedals in there (all of them being buffered). I am not that sure another buffer will be the solution unless it has some kind of level control. I've dealt with amps that lowered the volume if the FX loop was used no matter what.

 

[dan the man]

A buffer is not the same thing as an EQ (although an EQ can have a buffer). The EQ also, well, acts as an equalizer

And BTW, I see three Boss pedals in there (all of them being buffered). I am not that sure another buffer will be the solution unless it has some kind of level control. I've dealt with amps that lowered the volume if the FX loop was used no matter what.

I have a JHS Prestige laying around that I wasn't using, I can put that on there. Should do the trick. According to the description, the knob at 0-25% acts as a buffer. Put it first in the effects loop chain, right?

 

[loganflynn294]

Some amps just have shitty loops. If the volume drop happens with all pedals in the loop off, it’s the amp. If the volume is fine but drops only when pedals are turned on, that means the loop send level is too high and the pedals don’t have enough power to amplify the signal high enough to match the signal level the amp is sending. When you engage the loop without anything connected to it, the amp is still bypassing the loop, that’s why it’s not dropping volume when you engage it with nothing connected. Only solution is adding something to boost the volume in the loop like an eq. The loop could be modified internally, but that’s a whole different topic.

 

[Deadpool_25]

Yeah, you'll want to do some basic troubleshooting. Agree with starting with just trying a single pedal (I'd do the DD-3) with short cables and see what happens then. If the problem persists, try a different pedal (I'd try the TC next).

Also, I'd try this with the guitar going straight into the amp input and no pedals in between. It shouldn't matter, but...well...troubleshooting 101.

 

[dan the man]

I did some troubleshooting, but unfortunately I didn't have many short cables laying around to try. Tried one pedal at a time, and with any single pedal in the loop, the problem exists. Luckily, the JHS buffer seems to do the trick. This is why I hoard pedals... my mind changes and I find uses for pedals I didn't think I'd need lol.

Now I just gotta get a good power supply and a board for this mess.

Here's the updated pic, things seem to be working swimmingly now:

 

[Shask]

Could just be an impedance mismatch with your pedals. Some situations just dont agree with each other.