Thoughts: 100W (4 tube) vs 50W (2 tube)

[hsnyder]

Hey guys,

Well I'm starting a series of amp builds (yes, I do that), and I'm trying to figure out if I should be going for 4 bottle output sections or 2 bottle ones. Yeah I know that kt88 or 6550, etc, can get 100 watts with 2 tubes, but I'm more just asking about the number of tubes, since I figure that would make more of a difference than the actual power.

I'm especially interested in hearing from people who have owned two different versions of the same amp, like a 2203 and a 2204 for example, or any other amps that come in different power tube configurations.

I'm not particularly worried about headroom cause these are mostly for recording, and even if they aren't, they'll be mic'd live anyhow.

So, what are some people's thoughts? Is there a big difference?

 

[sprack]

I personally prefer 50W. I like more saturation on the backend and less tubes to replace.

 

[PD-Baraka]

you allways loose a little bass and headroom with 2 tubes vs 4, but both have their uses. I use 2 at the moment.

 

[jipchen]

I thought with the 4 tubes option you can just take out two of the tubes and it'll be the same as the 2 tube amp?

 

[MarcusGHedwig]

you allways loose a little bass and headroom with 2 tubes vs 4, but both have their uses.

Yup, headroom is still important in recording settings because you want the amp to remain punchy when cranked to where the speakers start breaking up nicely (which I'm pretty sure I prefer to power amp breakup, if my past amps' kinda farting out at extreme master volume positions is any indication). Still, I'd really like to get insight on the subject from guys who have been able to really experiment with power tube breakup (can't crank it that loud for long periods here )

Of course, Max/jipchen makes probably the best point of all haha - you have to halve the impedance on the amp output (if it's an 8ohm cab, use the 4 ohm output) and make sure you remove the outer pair of tubes, but I can't imagine it'd be hard to make all that switchable (not sure if it's that simple in multi-watt amps, probably not)

 

[hsnyder]

Of course, Max/jipchen makes probably the best point of all haha - you have to halve the impedance on the output (if it's an 8ohm cab, use the 4 ohm output) and make sure you remove the outer pair, but I can't imagine it'd be hard to make all that switchable (not sure if it's that simple in multi-watt amps, probably not)

Well a 50 watt amp should break up a 2x12 at the same level that a 100 watt breaks up a 4x12... and technically if the internal volume of the 4x12 is exactly twice the internal volume of the 2x12, then they should sound the same to a microphone that is right in the face of one of the drivers... At least in theory.

You can switch the ohmage and the number of tubes in use, that is true, though you need to do the switching somewhat cleverly (connect before detach) otherwise the flyback voltage will probably take out a bunch of parts in your power section possibly including the tubes.

I guess the real reason I ask is cause I'm trying to avoid having to use 100 watt transformers and go to the extra time, cost, and weight that a 100 watt output section means. But again the number one priority is the sound, so if that will suffer from lowering to 50 watts, then i wont do it.

 

[MarcusGHedwig]

Well a 50 watt amp should break up a 2x12 at the same level that a 100 watt breaks up a 4x12... and technically if the internal volume of the 4x12 is exactly twice the internal volume of the 2x12, then they should sound the same to a microphone that is right in the face of one of the drivers... At least in theory.

Definitely not in practice IME! Pretty sure more speakers doing less excursion means more/tighter bass for example, all other things being equal

 

[hsnyder]

Definitely not in practice IME! Pretty sure more speakers doing less excursion means more/tighter bass, all other things being equal

I meant when the 2x12 is driven by half the power of the 4x12. In other words if excursion and internal volume per speaker are the same.

 

[Trevoire520]

I had a loaner of a 100w Marshall DSL before my 50w version arrived. To my ears the 100w definitely sounded better. Bigger tighter bass, more clean headroom. It's not like I was cranking the master volume either.

 

[MarcusGHedwig]

I meant when the 2x12 is driven by half the power of the 4x12. In other words if excursion and internal volume per speaker are the same.

Kinda sounds like you're designing it with the intent that your customers run it through 2x12's, which may not be to everyone's liking

 

[hsnyder]

Kinda sounds like you're designing it with the intent that your customers run it through 2x12's, which may not be to everyone's liking

DEFINITELY true. I'm not really designing to sell - obviously I'd build what a customer wanted if they wanted to order one from me, I'm more just seeing what I can get away with in terms of building myself a bunch of amps for recording. It is sounding like most people think 4 tubes does sound both different and better, so I'll probably end up going that way.