Friedman Runt 50 watt head with fx loop issue

[Arbutt]

Good morning too you
I have been asked by a local guitar shop for my views on this issue

One of the staff members bought a Friedman Runt used. Found by using the amp worked perfectly and sounds great
when using the send and return there is a background noise ( ground issue to my basic ears ). The pedal board was looked and and the manager of the shop rebuilt it with new cables and new pedal power psu. The manager has 26 yrs shop experience and builds pedal boards always weekly,., checked all the leads and lead address, positions of psu and pedals, psu output voltages etc, Even breaking a ground somewhere to see if that cures anything This is happening in the shop/studio/home,

Pedalpower 2
strymon -el capistan
eh - micro pog
mxr -acid fuzz
jhs - sweet tea
Wah wah

all of these pedals were no issue with previous amp marshall head

With the pedal board plugged into a JVM 50 watt combo its good no issues
The manager took home the pedal board and tried it in his own amp Friedman brown eye no issues
The manager put his own pedal board that has no issues in the brown eye into the grunt, it was noisy

I had a quick look inside the amp. Solid state send and return, no viable issues seen

The amp owner has contacted David Friedman many times and he denies any issues with the fx loop
Both guys have searched the net and it apparently seems to be an issue with noisy fx loops

My question has anyone had this problem and found a cure
one of a few posts on the net
https://www.thefretboard.co.uk/discu...-friedman-runt
https://www.rig-talk.com/forum/viewt...?f=57&t=185597
https://www.thegearpage.net/board/in...noise.1805047/

I have to say i have not read these posts above
many thanks
A

[J M Fahey]

I have to say i have not read these posts above

Will you read our answers then?

1) do the most basic test with the simplest effects chain: plug a short cable fron send to return.

repeat with a long one. Any change?

2) test with a simple pedal, **battery powered** , so itīs fully floating and we remove supplies, outlets and external grounding from the equation.

Repeat with same pedal but now powered from a wall wart.

Plug both amp and pedal supply in the same extension so as to avoid "different outlets" blues.

Repeat plugging each supply (amp and pedal) in its own outlet.

3) identify noise properly: hum or hiss?

Because some of the links you did not read speak of hiss more than hum, very different.

Do all tests and post all results, even if "all are the same".

If available, post schematic, but at least a nice picture showing effects loop area, PCB both sides, maybe we suggest cutting and rerouting some track or wire BUT we need your data input.

[Arbutt]

Ive been told they have found a solution. a little bit of moving about has got the noise acceptable . Again this pedal board as it is through other amps quite, through this runt. its not perfect. but he is happy with it

I guess you have to play with the layout sometimes for each amp

I made it clear that i'm not getting involved with the amp for this fault
many thanks
Mr A

This post is now done

[Jquijano]

which effects processor would you recommend to be use in the effects loop of this amp?

Boss GX-100: https://www.amazon.com/Boss-GX-100-G...43&sr=8-1&th=1

Boss Gt-1000 or Line 6 Helix?

Easy to program and quality modulation effects.