# Peavey 6505+ head sounds rubbish with FX loop used?



## P-Ride (Feb 16, 2016)

Hey, I took my recently finished pedalboard into the studio to use with our 6505+ which runs into an Orange 4x12".

We immediately noticed the lead channel sounded really thin, nasal and rubbish.

Troubleshooting, we realised that pulling out the cables for FX send/return resolved the issue.

Today, I've discovered others have found the same problem and impedance mismatch has been suggested? It's been suggested I try using a patch loop between send/return to diagnose.

If so, I find it staggering that Peavey would sell an amp which has what seems to be a useless effects loop.

Any suggestions? Here's my setup, thanks.


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## jc986 (Feb 16, 2016)

I didn't have any issues like this when I had my 6505+. If you just take a patch cable from the send to the return, is the issue still present with the loop engaged?

If not then one or more of your pedals just might not be getting along with the loop depending on level and impedance. 

If the issue is still there with nothing in the loop except the patch cable then try swapping the tube that is driving the FX loop.


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## Slaeyer (Feb 16, 2016)

I had an 6505 myself some years ago and never had a problem with the fx-loop at all. 

I guess connecting the fx send with the return using a patch cable would be the first thing to do. If that's not the problem remove remove one pedal after the other from the fx-loop, starting with the Boss EQ.


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## CapnForsaggio (Feb 16, 2016)

Be really careful with those "True Bypass" switchers..... tell us more about those. Many of these have the line capacity of a 100' cable when "bypassing" effects. totally depends on the quality of the switcher.


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## mongey (Feb 16, 2016)

All fx loops are a trade off imho. My recto loop sucks. I only use it for delay. Everything Else I run out front. 

Best thing you can do is add 1 thing to the loop at a time and see where it gets unbearable.


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## USMarine75 (Feb 16, 2016)

Plug a cable from the FX send to the FX return. 
Play through the amp and turn the loop off and on. 
If the level drops with the loop on, you have a problem. If the sound remains about the same, the loop is working.
Peavey usually has a -10dB drop in the effects return for some reason. So there should be a small drop, but not what you are reporting. You can fix this with a line booster (there are also resistors you can mod to remove the line level drop).

Also, check that the FX loop 12AX7 tube (V3 spot, 2nd from power tubes) is not bad.


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## viesczy (Feb 16, 2016)

Dump all the effects and rebuild 1 at a time as the more you put into a chain the weaker chain becomes. 

In the studio, delay/chorus/phasing/reverb should be added to the track after it is recorded and not recorded a part of the track as it is recorded IMO. A killer sonic foundation (your root sound) is far more important than using your fave effects pedal. 

Good luck as hating your tone is a horrible situation!

Derek


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## mr coffee (Feb 16, 2016)

I have never experienced this with my 6505+ - as a matter of fact, when my son works as a roadie/stage hand, his instructions for troubleshooting a failure include just straight pulling the send and return connections. The difference is all but unnoticeable.

As has been mentioned, check the amp's functionality first by comparing tone with and without a short patch cable connecting the send directly to the return. If you notice a difference, there is a ~problem~ (not a design issue but a failure) within your amp, most likely a bad tube in the loop buffer. They're pretty easy to replace. The tube in question would be V3, it should be the second from the left when you are looking at the back of the amp.

If the sound remains the same with a patch cable in the loop, check all of the cables used. If all cables are good, begin adding pedals. When you reach the point of testing with the delays, try them inline without the bypass first, then add the bypass. It should be very apparent when you find the culprit - I don't expect a cumulative deterioration of tone here, but a clear difference with the addition of one pedal.

-m


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## scrub (May 9, 2016)

Glad you brought up this topic. I have a 6505+ 112. I run a boss dd7 delay through the loop and tone I get is really undesirable. The gain is increased dramatically to the point where the overall tone sounds very harsh and somewhat grainy to the point where it is essentially clipping. and I am not able to achieve a good delay tone at all. Any advice for this type of problem? bad tube? Is the signal to hot going in?


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## P-Ride (May 9, 2016)

scrub said:


> Glad you brought up this topic. I have a 6505+ 112. I run a boss dd7 delay through the loop and tone I get is really undesirable. The gain is increased dramatically to the point where the overall tone sounds very harsh and somewhat grainy to the point where it is essentially clipping. and I am not able to achieve a good delay tone at all. Any advice for this type of problem? bad tube? Is the signal to hot going in?



I believe your 112 has a very specific problem with the FX loop which is known and I think had a fix that involves changing a resistor?

Annoyingly, my issue is much less documented.


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## KailM (May 9, 2016)

^^^(edit: @ Scrub)

1. You should start your own thread.

2. I'll help you anyway.

3. The 6505+ 112 has a crappy buffer in the effects loop. Whatever Peavey's intentions were, it didn't work out. As soon as you plug anything into the effects loop (even just a patch cable), the buffer is engaged and it adds a ton of fizz and sucks the life out of your low-end.

It's an amazingly easy and cheap problem to fix though. Just solder a .022 uF capacitor in parallel to the legs of resistor R 86 (located directly behind the effects loop "send" jack. This is Peavey's recommended solution to the problem, by the way. I've done it. It works.


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## robski92 (May 9, 2016)

> I believe your 112 has a very specific problem with the FX loop which is known and I think had a fix that involves changing a resistor?
> 
> Annoyingly, my issue is much less documented.



You are correct. By adding a resistor (there are youtube guides) it fixes that issue with the FX loop for the combo. As far as your issue goes P-Ride, I'm not really sure. I always thought I heard good things about the loop on the head version.


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## scrub (May 9, 2016)

KailM said:


> ^^^(edit: @ Scrub)
> 
> 1. You should start your own thread.
> 
> ...



Thanks for the tip.


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