stupid question about my beloved Sceptre

[Bhairab108]

i know very little about amps other than what i like and how to change tubes,is there some reason  why my sceptre has a solidstate rec,instead of a tube? am i correct in my assumption that this is how they came? can i chuck the dash-darn thing and put a tube in it,cuz i sure want to........

thanks!
B

[brianmooredc1]

why would you want to? there are no problems with solid state rectifiers.... I think that this is a misconception with amps nowadays, I hear people all the time talking about how important it is to have tube rectifiers, but I doubt many of them actually know what they are. for the ones that don't know, I will explain. tube amps all run on dc power which is of course battery. unfortunatly, we plug them in to normal 110 volt AC power outlets. we use rectifiers to convert the power to DC, so that we can use them without insanely large batteries I honestly see no pros to having a tube rectifier, because the solid state does not have to "warm up". solid state rectifiers will also be slightly more responsive, and will not be as "spongy", and will have less sag.

[Bhairab108]

right on!  i have no problem leaving it the way it is. i am a tinkerer,i like to change stuff and fiddle.i appreciate your insight . so does the rectifier affect tone at all? i hate to sound ingnorant.i know i love old sunns cuz they are loud and dark,but thats it.

again ,thanks for your insight!
B

[brianmooredc1]

well...this is very subjective, and I know that you will hate for me to say this because it doesnt really answer your question. I honestly can not tell a deference between the two, but I know that some people are hardcore tube "heads" and only love tubes...for everthing, especialy being in such a retro everything time period. obviously these people are very biased. I would not change it. even some very expensive boutique amps come with solid state rectifiers, alessandro amps for instance. also some amps like badcats, come with both so that you can switch between the two, depending on which one you like.

[JoeArthur]

The only time you would be able to tell the difference between a tube or solid-state rectifier is when you're running the amp full out.  The tube rectifier will run out of current capability earlier, and because of a 35 volt or more drop across it, will cause the power output stage to distort earlier due to a reduction in B+. Pushing it further will result in sag.  Some people like saggy power supplies, others don't.

While there may indeed be tube only bigots, the same result can easily be simulated by using a 100 ohm 5-10 watt power resistor after the solid state diodes and before the first filter cap.  To further enhance the effect, using a zener diode of 36-40 some odd volts will reduce the B+ voltage.  Add a switch to bypass or short circuit across the resistor and/or zener network and you have the best of both worlds.

Have you seen what GZ34 tubes are going for these days?

Oh and one more point.  Amps with existing rectifier tubes have a separate heater supply winding of 5 volts off of the power transformer.  If you don't have this secondary winding on the power transformer, adding a tube rectifier to a solid-state rectifier equiped amp is going to be somewhat difficult than you would expect.

[Bhairab108]

sweet! thanks for all the info. your tech talk is enlightening if not a little baffling for a non techy dude such as myself! i figure i should let it be,i love it just how it is,and i (it) would most likely not benefit from any change. thanks for all your help,guys!! joining this board has been way worth while!!

B

[EdBass]

The only time you would be able to tell the difference between a tube or solid-state rectifier is when you're running the amp full out.  The tube rectifier will run out of current capability earlier, and because of a 35 volt or more drop across it, will cause the power output stage to distort earlier due to a reduction in B+. Pushing it further will result in sag.  Some people like saggy power supplies, others don't.

While there may indeed be tube only bigots, the same result can easily be simulated by using a 100 ohm 5-10 watt power resistor after the solid state diodes and before the first filter cap.  To further enhance the effect, using a zener diode of 36-40 some odd volts will reduce the B+ voltage.  Add a switch to bypass or short circuit across the resistor and/or zener network and you have the best of both worlds.

Have you seen what GZ34 tubes are going for these days?

Oh and one more point.  Amps with existing rectifier tubes have a separate heater supply winding of 5 volts off of the power transformer.  If you don't have this secondary winding on the power transformer, adding a tube rectifier to a solid-state rectifier equiped amp is going to be somewhat difficult than you would expect.

+1

Amps with existing rectifier tubes have a separate heater supply winding of 5 volts off of the power transformer.  If you don't have this secondary winding on the power transformer, adding a tube rectifier to a solid-state rectifier equiped amp is going to be somewhat difficult than you would expect.

Yeah, add a new power transformer to the cost of a GZ34 and your better off just buying a tube rectified amp!

And....While SS rectifiers are more efficient than tube rectifiers, they also facilitate a gradual turn on of current through the circuit, as a tube only gradually gains the ability to conduct current as the heater gets the tube to a specific temperature. A  SS rectifier blasts the cold/idle circuit (and the other tubes if not in standby) with full power at turnon. Some EE's attribute the longevity of old (before the common use of SS rectifiers) tube amps to this feature of tube rectification.
Even so...
I'm pretty tube oriented when it comes to amps, but particularly as I'm a bass player, I think the technical superiority and therefore the increased current efficiency of SS rectifiers far outweighs any percieved "mojo" of tube rectified "sag".
I know guitarists who would fight me to the death about that, but to each their own!

the same result can easily be simulated by using a 100 ohm 5-10 watt power resistor after the solid state diodes and before the first filter cap.  To further enhance the effect, using a zener diode of 36-40 some odd volts will reduce the B+ voltage.  Add a switch to bypass or short circuit across the resistor and/or zener network and you have the best of both worlds.

Not the versatility of JoeArthurs mod, but in my tube rectified Sunn's I use these;
http://www.webervst.com/ccap.html
rather than modify the original power supply, they are only about $20 and it's plug 'n' play!

 

[Soundmasterg]

+1 on the Copper Caps. I used a WZ34 in my modified 200S Sunn and it works like a charm.