Engl Tube Amp Mod.

[Hulk]

I have an Engl 850 Rackhead guitar tube amp - it's a high-gain amp and I love the sound of it but there has always been a little issue...

There is something "harsh" or something in the upper mids that "hurt" my ears just a bit - it's nothing serious and it's something that I can live with but now that I'm more involved in DIY I thought that I might could do something about it. I cannot EQ my way out of it nor can I change it with diffent mic possitions it's something "native" to the sound of this amp

I don't want any major change in the sound but just a little more smoothness in the sound sort of a gentle "grinding of the corners" at the same time the operation must not alter the sound too much because I like how it sound so I don't know if you can follow me here... :guinness:

I only have one picture of the preamp section for you to see but what would you suggest - a recap?? There WIMA caps in there and TL071 and TBA820 op-amps....

 

[amorris]

you could try different speakers. I think that the new amp combos are harsh like you say and celestions are great for gtr amps. maybe an old jensen blue. they can really change the sound.

 

[Hulk]

I use the standard Celestion G12T-75 ones - mayby the Celestion Vintage 30 would be better...??

 

[MikoKensington]

The 75 watt Celestions are harsh from about 4K on up. Get some Greenbacks or some 30's and you'll be a lot happier.

 

[NewYorkDave]

I worked on a few Engls about ten years ago. That's an experience I never, ever want to repeat. If you pull out the boards to swap caps or whatever, expect to spend a few hours troubleshooting afterwards to figure out why the amp doesn't work anymore.

German equipment has a reputation for being well-made, but there's an exception to every rule--and Engl is one of those exceptions.

By all means, try new speakers first--or try anything that doesn't involve disturbing the amp's internals.

 

[12afael]

wima are good caps. a friend of mine say that if you use only one kind of cap you get a hard sound, if you mix some kind of caps you will get a better sound.

you can try to mod the tone stage but it use LDR instead of pots I think .maybe a change in the caps value.

I build recently a mix of engl preamps . it sound well .

NewYorkDave
do you have some engl schematics to share?
can you tell me more on the construction of the amplifiers? it seems to me that it has good components and sound well. they are so badly constructed?

 

[mikka]

Agree with above re: speakers. I wouldn't touch the circuit until you've taste tested a nice assortment of speakers. I find the 12T-75's harsh also.... they just don't have the tone I seek.

I'd recommend trying Vintage 30 Celestions, Celestion Greenbacks, and Fane Alnico...... just for a quick comparison. Also I'd talk to Weber VST for their recommendations.

 

[Peter Simonsen]

I agree as well try out new speakers...I have just heard these "The red line" Tone Tubby speakers..Jesus Christ -...some sweet sounding speakers..!!! The best I have heard in a very very long time..(new production speakers). No harsh tones from these..

Kind regards

Peter