BadComrade wrote:

Snowblinder wrote:...Ampeg SVT Classic 300 watt head into an Ampeg SVT 8x10 cabinet. I always use a Tech 21 Sansamp Bass Driver pedal with this setup.

I don't get it. Why would you use a pedal that can sound exactly like an Ampeg SVT, going in to an actual SVT?

It tightens up the sound and gives a considerable volume boost.

D'Piucchstre wrote:

llllllllllllllllllllllll wrote:

llllllllllllllllllllllll wrote:Mesa Boogie D-180, ampeg 4x10. About to trade the cab in for a Bag-End 1x15.

I have 6l6's in my head at the moment, does anyone know if I can change to different types of tubes for a little more clean head room and power?

6550's or KT-88's should give you substantially more clean headroom. Your power output is limited by the PSU and the output transformer, so using tubes with a higher voltage rating won't increase the power output of your amp, but will increase your clean headroom due to the fact that it takes more power to make them clip out.

what kind of modifications would have to be done, if any, to use these tubes. is this sort of thing best left for a tech?

D'Piucchstre wrote:

llllllllllllllllllllllll wrote:

llllllllllllllllllllllll wrote:Mesa Boogie D-180, ampeg 4x10. About to trade the cab in for a Bag-End 1x15.

I have 6l6's in my head at the moment, does anyone know if I can change to different types of tubes for a little more clean head room and power?

6550's or KT-88's should give you substantially more clean headroom. Your power output is limited by the PSU and the output transformer, so using tubes with a higher voltage rating won't increase the power output of your amp, but will increase your clean headroom due to the fact that it takes more power to make them clip out.

Also, I assume that replacing the power transformer with a bigger one is an expensive job?

llllllllllllllllllllllll wrote:what kind of modifications would have to be done, if any, to use these tubes. is this sort of thing best left for a tech?

You will most likely need to change the pinouts on the power tube octal sockets, a few caps, and the screen resistors, as well as re-bias to accept the differant tubes. 6550's and KT88's are pin compatible with EL-34's, and some 6L6 configurations, but not all 6L6 configurations.

I would leave this and all other amp work to a qualified tech, as the high voltages present in tube amps (ranging between 400vdc to 800vdc for the average 50-100 watt amp) can at best give you a shock you will remember for the rest of your life, or outright kill you.

Even if you know your way around high voltage electronics (Which you appear not to know too much about) you would still need a dummy load resistor, a multimiter, and an oscilliscope to properly bias the amp.

As far as replacing the transformers to get more wattage from the amp, you will need to replace both the output transformer and the entire PSU (including transformer) to ensure not only proper voltage supply, but also to step down the voltage/resistance to levels usable by a typical 4-16 ohm speaker configuration.

As far as transformers go, yeah, replacing them is an expensive proposition, as the PSU transformer/OPT configuration makes up the bulk of the cost of a tube amp. I have no idea of what type of wattage you want to run, however, a good transformer repacement kit for a 100 watt guitar amp will cost you between $400-$600, for the parts only. Labor to install them will also cost you quite a bit, as replacing transformers is a quite bit more labor intensive than converting you amp over to run on differant output tubes. --The transformers are literally the 'heart and soul' of your amp.

If you need a loud amp, check into getting something like a Sunn 2000s, an old (NOT the reissue!!) Sunn Model T, Sound City 200, or an Ampeg SVT .

Once again, I'd like to stress that digging around in the guts of a tube amp CAN KILL YOU!!!

Anyone interested in this?:



No tubes, uses 6 EL34s. I've had it since 1978. Very low hours, probably needs a cap job and general going-over. Very clean, stored in a dry clean environment.

Too big 'n loud for me.

zom-zom wrote:Anyone interested in this?:

No tubes, uses 6 EL34s. I've had it since 1978. Very low hours, probably needs a cap job and general going-over. Very clean, stored in a dry clean environment.

Too big 'n loud for me.

I'n not knowlegeable about the SMF Tour Series Sound City's. Did they have the dreaded active preamp of the older MkIV series? --The MkIV series are sort of OK for bass depending on the model, but the even older MkIII series were the shit as far as Sound City goes. --They were last amps that Dave Reeves designed before launching Hiwatt.

zom-zom wrote:Anyone interested in this?:

No tubes, uses 6 EL34s. I've had it since 1978. Very low hours, probably needs a cap job and general going-over. Very clean, stored in a dry clean environment.

Too big 'n loud for me.

i am. how many watts?

Aren't all preamps "active"? It does have active tone controls, they don't suck but they're just a bit touchy to dial in your sound. I was able to get some very cool sounds out of it.

It's rated at 150 watts. Very loud. I have more photos, or can take more if you want to see the innards. It's wired as good as any Hiwatt I've ever seen.

I might be, you can pm me with a price if you'd like.

D'Piucchstre wrote:

llllllllllllllllllllllll wrote:what kind of modifications would have to be done, if any, to use these tubes. is this sort of thing best left for a tech?

You will most likely need to change the pinouts on the power tube octal sockets, a few caps, and the screen resistors, as well as re-bias to accept the differant tubes. 6550's and KT88's are pin compatible with EL-34's, and some 6L6 configurations, but not all 6L6 configurations.

I would leave this and all other amp work to a qualified tech, as the high voltages present in tube amps (ranging between 400vdc to 800vdc for the average 50-100 watt amp) can at best give you a shock you will remember for the rest of your life, or outright kill you.

Even if you know your way around high voltage electronics (Which you appear not to know too much about) you would still need a dummy load resistor, a multimiter, and an oscilliscope to properly bias the amp.

As far as replacing the transformers to get more wattage from the amp, you will need to replace both the output transformer and the entire PSU (including transformer) to ensure not only proper voltage supply, but also to step down the voltage/resistance to levels usable by a typical 4-16 ohm speaker configuration.

As far as transformers go, yeah, replacing them is an expensive proposition, as the PSU transformer/OPT configuration makes up the bulk of the cost of a tube amp. I have no idea of what type of wattage you want to run, however, a good transformer repacement kit for a 100 watt guitar amp will cost you between $400-$600, for the parts only. Labor to install them will also cost you quite a bit, as replacing transformers is a quite bit more labor intensive than converting you amp over to run on differant output tubes. --The transformers are literally the 'heart and soul' of your amp.

If you need a loud amp, check into getting something like a Sunn 2000s, an old (NOT the reissue!!) Sunn Model T, Sound City 200, or an Ampeg SVT .

Once again, I'd like to stress that digging around in the guts of a tube amp CAN KILL YOU!!!

Yeah I don't think any of that is necessary. Going to get another cab and work from there.