Engl Thunder 50 valve swap

[NumbSkull]

I bought an Engl Thunder 50 , when it arrived it has a loud buzz, much louder than the sound of the guitar that was barely audible and very distorted.

I changed all the valves for these :

Valveset for guitar amp (12ax7 and EL34) | eBay

Valveset for guitar amp (12ax7 and EL34). Brand new but lived in my spares drawer for 20 years as I never needed them. 4 Ecc83 (also known as 12ax7) and 2 EL34 (matched pair) Bought new by me direct from Marshall. I had a Marshall JTM60 so perfect for that but suit any amp that uses these...

www.ebay.co.uk

and now it sounds fine, no buzz.

My question is do I need to do any rebiasing or similar,
or can I just crunch on.

 

[Georgiatec]

I bought an Engl Thunder 50 , when it arrived it has a loud buzz, much louder than the sound of the guitar that was barely audible and very distorted.

I changed all the valves for these :

Valveset for guitar amp (12ax7 and EL34) | eBay

Valveset for guitar amp (12ax7 and EL34). Brand new but lived in my spares drawer for 20 years as I never needed them. 4 Ecc83 (also known as 12ax7) and 2 EL34 (matched pair) Bought new by me direct from Marshall. I had a Marshall JTM60 so perfect for that but suit any amp that uses these...

www.ebay.co.uk

and now it sounds fine, no buzz.

My question is do I need to do any rebiasing or similar,
or can I just crunch on.

50w out of two EL34's means it's a fixed bias amp and will need re-biasing now it has the new valves in.
Failure to do so could result in you needing a new pair of EL34's in short order.

 

[nasticanasta]

I would, but remember to get the tightest matching tubes, because they are fixed bias.
I'm running 2 Thunder heads in stereo...love it