I want a Science Amplifier

[Iommic Pope]

Yeah, I know they're commonly used in high end tube amps/receivers for hifi purposes, but I see that description carry over to guitar amps sometimes and it baffles me.
I guess the Klon-ish nature of descriptions like that is generally offputting.

Yeah, I need more articulation at ridiculous volumes.
Who doesn't?

[waltdogg]

KT88s and 6550s offer incredible headroom and clarity when you're playing so loud it feels like your head is going to explode

Ugh. This. So much. An SVT pumping on all cylinders is awesome. Their build quality is lacking though. Can not wait to get my Mother. Ought to be glorious. (I've heard the clips, messed around with an F.A.C, and really like the tone you get from the Hiwatt circuit.)

I should figure out how to run my record player directly into my Mother's power amp...

[Iommic Pope]

Now that^ is an idea!
Everything should have a FAC, in my opinion.

[waltdogg]

F.A.C. all the way. Being able to revoice your amp on the fly is probably the best feature ever introduced to amps besides a master volume.

[Iommic Pope]

Indeed.

[Bellyheart]

Is the upgrade just the tubes or is the circuit different?

[waltdogg]

I'd ask Alex, but it's most likely an output transformer upgrade to handle the higher wattage of KT88/6550s. I wonder if you could still use 6L6s and El34s in KT88 versions of the Hellhawk, Decolonizer and and Street Sweeper... I love these amps.

[Iommic Pope]

Poweramp section design is usually a little different (only a little), although some designers go from the ground up and choose specific transformers and design an amp around a KT88 output section.
In this instance, I'd say it wouldn't be a huge change, although Alex would be able to tell you (Walt nailed my answer).

[Science Amps]

Hey Everyone! Just to clarify, the KT88 option for the models that accept multiple tubes types is just the difference of the power tubes themselves. No changes to the circuit, output transformer, etc. as it's not necessary. The cost difference is merely the wholesale cost difference of the tubes compared to 6L6s or EL34s. No matter which tubes the amp ships with, they can be swapped at anytime for another type with just a bias adjustment using the controls on the rear panel.

While KT88s have the potential to put out more power (as they do in the 200W Mother model), they won't unless the amp is designed to do so (different transformer specs & power supply). Therefore, putting KT88s in the Hellhawk, Decolonizer, Sister, or Street Sweeper is only for tonal variation and convenience, rather than power increase. And on that note, the tonal difference is practically negligible considering all the other factors in the signal chain (and at the volumes most of my customers plat at!). The differences are more apparent when overdriving the power tubes, but that does not happen often or in isolation (meaning there are other types overdrive from the preamp, driver (and pedals, of course) co-mingling, and so it's hard to tell if what you're hearing is the difference of the power tubes or not.

Another consideration is that what one may perceive as a difference in power tube type alone is sometimes partially the interaction between the tubes, output transformer, surrounding circuitry, and bias point. Basically, it's an 'everything affects everything' situation, even when you think you're just A/B'ing tubes. Most people rarely get to A/B tube types in the same amp back to back, and often attribute the tone of their amp to the power tube type. For example, 6L6 = Fender. Put EL34s in a Fender circuit and it still sounds 99% like a Fender

I think the idea of KT88s being more 'HIFI' is also a bit of a myth. There are lots of HIFI amps that using all varieties of preamp and power tubes, which have accurate sound reproduction. It's really the circuit that matters most. So why offer different tubes types? Because I really have no reason not to, and while the differences are subtle in my opinion, they are there and justify experimentation.

I've been working on a new website to replace my current lame one, and I really wanna do some clips comparing power tubes in the same amp so folks can decide for themselves. Hope that helps, and sorry for the rant!

...Oh, and while I'm here, as far as cabs, we can really do anything, but custom charges may apply. We actually already have a 6x10 sealed bass cab, and ported 1x15 and 2x15 bass cabs. We have a 6x12 for guitar too. I've just been too busy to put anything online about them. Lots of stuff possibilities!

Thanks again for all the interest and support here. It's really appreciated.


Alex

[Iommic Pope]

Dude that was a great post, thanks for clarifying!
A shoot out between tube types would be rad sticks.

[waltdogg]

Then... I can put KT88s in my Hellhawk with just a rebias?

If anyone is interested Here's a bunch of tracks where I used my Hellhawk for guitar. Close mic'd with an SM57 and MD 421-II. No effects, just a little bit of mastering compression to get it loud enough to listen to. It's a Gibson Les Paul through my Hellhawk and a closed back 2x12 with V30s. According to Alex it's a pretty accurate recording of the Hellhawk through those speakers.

https://soundcloud.com/thefalsejesii/sets/great-walls

[Science Amps]

Then... I can put KT88s in my Hellhawk with just a rebias? [/url]

Walter, people kept asking about KT88s in the Hellhawk, but it wasn't possible because because I was using a Marshall replica power transformer which could not support current draw of the KT88s biased at 35W. I've since switched to the same custom PT I use in the other 100 watters that can handle the extra current draw of the KT88s. That said, you can still totally use KT88s in your amp, just bias them at 25W like an EL34. There is also a chance there may not be enough bias range, but it may be okay since your tech already changed that one resistor to accommodate the NOS 6CA7s you had. It's no big deal to bias them at 25W, and that's exactly what Marshall did on their import models using 6550s.

[Iommic Pope]

Ok then.
My next question would be about el34bs and whether or not youre able to ship with them in there/like them enough to use them/hate them and won't use them.

I know that's splitting hairs but I really like them in British-styled amps.

[waltdogg]

In that case then I probably wont bother doing it. Yeah he just added the extra resistor as you suggested to make it easy and reversible. The bias range is much wider and more sensitive now.

My Hellhawk came with Ruby EL34B-STRs, they were alright. I'm running JJ E34Ls now, they sound super close to the original Tesla double getter EL34.

[Bellyheart]

Thanks for the answers