Ampeg SVT-CL - gain distortion

[JFALTERW]

Hey, recently got an Ampeg SVT-CL (lucky me) and have seen in plenty on vids how cranking up the input gain gives an overdriven/distorted signal. Yet try as i might i cannot seem to replicate this with my head. I use a Squier 70's vintage modified passive Jazz bass and have heard you only really get some grint if you have an active bass, but i'm not sure.

Any and all help/advice would be great!

Thanks again

[Handwired]

You should get more than enough grunt with a passive bass - I do with mine.

[JFALTERW]

Aye, but i don't. Thus my issue :'(

I'm thinking a pre-amp valve or two has gone, but not sure. A bit of help from anyone who has had a similar issue would be fantastic!

[Billy Apple]

Did you get the head new or s/h? If it was second hand it might be worthwhile getting it serviced by a tec. Could you post up a pic of the settings on the head when you think it should be grinding, and have you checked both bias lights are green on the back?

[JFALTERW]

It was second hand.
Both Bias lights are fine, when warmed up and connected to a cab. So i don't believe it's the drive tubes. I wouldn't mind taking it to a tech, just a lil nervous if it needs nay work. I know tube heads are expensive to service :/

And i have had the gain all the way up, and it doesn't really distort or grind at all, just sounds very 'high gain' if that makes any sense...

Edited February 7, 2014 by JFALTERW

[Billy Apple]

What area do you live in? Some one here might be able to recommend a decent tec

[Billy Apple]

And what cab are you going through?

[JFALTERW]

I live in Ormskirk, but practice in Preston. So NW England really.
I'm not going through a great cab either, trying to get a better one. I have a peavey TVX 4 ohm which is showing its age, and a Behringer BA410(They're both 4 ohms btw. and i don't run them both at the same time, i've tried one and then the other)

Not great cabs but all i've got atm...

[Marsy]

'And i have had the gain all the way up, and it doesn't really distort or grind at all, just sounds very 'high gain' if that makes any sense...'





I'm not sure it does..?
If you crank the gain to max but keep the volume relatively low with the 'master' then your not gonna get distortion.. Just use a pedal perhaps?

[Anders]

I also have a CL. I have tried a few different preamptubes.They all have given some kind of distortion with the gain-knob on full.I have noticed that it makes quite some difference what preamptubes you use,but I have never tried a 5751 for instance,or even lower gain.
http://www.tubeampdoctor.com/en/shop_Other_brands_OEM_Tubes_Preamp_doubletriodes/5751_GE_NOS_USA_3348
Maybe the previous owner put some very low-gain preamptubes in it.It's easy to check.Unscrew the 4 screws on top and carefully pull the frontplate out until you can reach the two preamptubes.

[VTypeV4]

[quote name='JFALTERW' timestamp='1391811209' post='2361698']
I live in Ormskirk, but practice in Preston. So NW England really.
I'm not going through a great cab either, trying to get a better one. I have a peavey TVX 4 ohm which is showing its age, and a Behringer BA410([u][b]They're both 4 ohms btw[/b][/u]. and i don't run them both at the same time, i've tried one and then the other)

Not great cabs but all i've got atm...
[/quote]

I believe your amp will happily work at two ohms so you could run both cabs together.. Doesn't solve your gain issue but might be of use to know..

[Roland Rock]

[quote name='Marsy' timestamp='1391812061' post='2361708']
If you crank the gain to max but keep the volume relatively low with the 'master' then your not gonna get distortion.. Just use a pedal perhaps?
[/quote]

You should get some distortion with gain on full, regardless of where the master volume sits, as long as the signal is hot enough to overdrive the preamp valves.

Cranking the master volume is where the lovely power amp valve distortion will kick in.

My first thought was how hot is the signal from your passive bass? On my valve amp with gain cranked, I get minimal distortion through my passive, yet plug in the active and it can be a real monster.

When I put my passive bass through a clean boost (eg Markbass Superbooster) it gets filthy.