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Uncle GAS Needs You: Help Design an All Tube Amp!!!

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#181
cabcreaser said:
I love the philosophy behind the amp (using 60s bass sounds as a reference). So far, the idea looks fantastic (IMO more bass amps should use 6SL7s for the preamp tubes). In fact, the bass tone that inspires me most is a really well maintained mid-60s B15 before it breaks up-unfortunately, that is pretty early.
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I really dig the B15's. Actually I heard one at the latest guitar show here in town and I really dug it, but there was not a lot of cleans there. That started me thinking, Hmmmmm, wonder what a high power B15 might sound like? The idea has since turned into a hybrid design, but I'm hoping that the tone of the B15 will be attainable or at least a close cousin of it. :)

It sounds like that really clean (in a tubey sense) but fat sound (though not grindy or muddy) you hear on countless older recordings is the goal, and if that is achieved I would definitely want to buy one. In fact, if you need any local bass players to check out prototypes, I live in Dallas and would love to help you in any way possible.
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Man that's great! I would love to have you play test it. Keep in touch and when I have something, we can run through it together and flesh out the amp. Thanks!

The only features I don't think I have seen mentioned that would appeal to me, I apologize if these have, is the ability,like the new Sadowsky head has, to use different power tubes and also a switch that can cut the power in half (preferably by reducing the number of tubes used as opposed to the pentode/tetrode switch like the Demeter power amp has). I love KT-88s/6550s for live applications, but I really love what 6L6s do to a bass sound for recording. In addition, since you have been convinced to bring the power up to 300 watts (which is a great thing for a 3000 dollar amp), the option of cutting the power in half as well as variable fan speeds could make it a perfect amp for the studio.
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Because of the ORBA, I will be able to use KT88's and 6550's. I'm going to try to use EL34's and 6L6-GC's as well. All of which can be biased correctly using the ORBA.

Regarding the half power idea, that is easy to do, but the bias on the amp will need to be checked once the half power is switched. That gives me some ideas..... Hmmmm

Regarding the variable speed fans, those are standard issue for all of my amps. :D

ps- how is the naming process coming?
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I'm still working on it and still accepting entries. Tell you what. Whoever picks the winning name will get $100.00 of their order! How does that sound?
 
#182
Fretless5verfan said:
i've never had the pleasure of using a tube head in the studio sadly, but what are the benefits of running half power? I'm sure it's quieter (more quiet?) but is there anything else?
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Less power = More overdrive and compression at a given SPL. This may or may not be needed depending on the gig or the tone desired.
Variable speed fans would be a very nice touch.
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Done. :)

How IS that naming process coming? :D
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Still accepting entries. :)
 
#183
Kelly Lee said:
On the rackmounting thing again here... just for reference the Trace Elliot HexaValve uses six 6550 powertubes, puts out 380 watts, and mounts in a 4sp rack case. :D
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The only difference here is that is a dedicated rack unit that is probably the full depth of the rack. Since I'm building this primarily as a head, I have about 9" of chassis depth to play with. This means that as I add more to the chassis, the chassis has to grow lengthwise.
 
#185
I am so incredibly impressed by this.

If my financial situation continues to improve... I have full intentions of buying one or at the least looking into the finished product at great length.


My name choice would be 'Leviathan'


I'm excited about this
 
#187
SnoBassMan said:
I am so incredibly impressed by this.
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Thanks! For some reason, you guys actually seem to be getting what Jackson Ampworks is all about. Perhaps I'm not marketing myself to guitar players well, but I feel like I have stumbled onto a whole new market for my products. Funny how things work out. :)

If my financial situation continues to improve... I have full intentions of buying one or at the least looking into the finished product at great length.
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Well this product won't be released for while, so hopefully things will turn around for you. Best wishes!


My name choice would be 'Leviathan'
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I really dig this! :)
 
#188
JacksonAmpworks said:
The only difference here is that is a dedicated rack unit that is probably the full depth of the rack. Since I'm building this primarily as a head, I have about 9" of chassis depth to play with. This means that as I add more to the chassis, the chassis has to grow lengthwise.
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Cool. I can see where you're coming from. :cool:

Maybe down the road, with the success from this amp, you'll decide to expand your line with a rack unit. ;)
 
#189
JacksonAmpworks said:
You're right on this one. From what I understand, most Ultra-Lo switches just shunt some of the highs to grounds so you "perceive" an increase in bass. I'll have to test all of this. :)
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Mark this day folks, i was right for once. This may never happen again :smug: :D

The half power thing makes much more sense now. I don't ever go near foghorn tonewise so i'd bank on that not being too big of an issue for me.

As far as the second gain stage goes, i don't know if i'm thinking about this properly but if i have gain 1 to apoint where i'm playing clean, and i switch gain 2, does that suddenly increase the gain overall (increasing the volume as well?) or does it switch to a different gain setting that you can have at level with your gain 1 volume? If it does stay at the same volume, i'm thinking it should be the beginnings of obvious OD. I'd LOVE to be able to just pop a niced OD'ed sound in and out without a ton of pedals or messing with the amp. :hyper:

Variable fans = u da man :cool:

And another name entry from me, "The Pacific" :D
 
#191
Fretless5verfan said:
The half power thing makes much more sense now. I don't ever go near foghorn tonewise so i'd bank on that not being too big of an issue for me.
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I'm still not sold on the idea. I see that it might be cool, but it might cause more problems than it solves. If this amp were cathode biased, I would say not problem, just stick in in there. But since this amp is Fixed bias, if you took the amp from say, 300W to 100W (6 tubes down to 2 tubes), the decreased load would cause and increase in plate voltage, as well as the negative voltage used to bias the tubes. By doing this, the bias point would certainly change and everytime the amp is selected to 100W, the amp would have to be rebiased. I might be able to find a clever way around this, but after giving this idea a quick glance, I can see that there are come caveats.

As far as the second gain stage goes, i don't know if i'm thinking about this properly but if i have gain 1 to apoint where i'm playing clean, and i switch gain 2, does that suddenly increase the gain overall (increasing the volume as well?) or does it switch to a different gain setting that you can have at level with your gain 1 volume? If it does stay at the same volume, i'm thinking it should be the beginnings of obvious OD. I'd LOVE to be able to just pop a niced OD'ed sound in and out without a ton of pedals or messing with the amp. :hyper:
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I'll certainly test this idea, and see what we come up with. As long as it does compromise the clean tone of the amp, this might make it into the amplifier.

Variable fans = u da man :cool:
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Cooling fans extend the life of tubes, the amplifier etc. All very good things! :)

And another name entry from me, "The Pacific" :D
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Not a bad idea. Kinda eludes to the music coming out of California in the 60's. :D
 
#194
JacksonAmpworks said:
I'm still not sold on the idea. I see that it might be cool, but it might cause more problems than it solves. If this amp were cathode biased, I would say not problem, just stick in in there. But since this amp is Fixed bias, if you took the amp from say, 300W to 100W (6 tubes down to 2 tubes), the decreased load would cause and increase in plate voltage, as well as the negative voltage used to bias the tubes. By doing this, the bias point would certainly change and everytime the amp is selected to 100W, the amp would have to be rebiased. I might be able to find a clever way around this, but after giving this idea a quick glance, I can see that there are come caveats.
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Steal Trace Elliot's idea and just have a switch that lifts the cathode grounds off the power tubes: no impedance or plate voltage issues at lower power.

Count me in, too. Howsabout a chrome treadplate face ala the Mesa Recto series?
 
#196
Psycho Bass Guy said:
Steal Trace Elliot's idea and just have a switch that lifts the cathode grounds off the power tubes: no impedance or plate voltage issues at lower power.
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That's what I was thinking, but since all of my amps use 2 output tubes I've never been able to test this. Are you saying that the plate voltages will not change when the cathodes are lifted? If this is true, there's the solution! :D

Howsabout a chrome treadplate face ala the Mesa Recto series?
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:rollno: :D
 
#197
JacksonAmpworks said:
Yeah, that shouldn't be too hard. I'll just add a switch that selects from either point and then convert it to low impedance. But as always, saying something is easy and actually doing it are two different things. :)
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omfg,

that will SO RAWK. :hyper: :bassist: :cool:

basstasters be dammed, this amp'll be makin' some UNREAL clips o' joy!

and has the "overdrive" been decided yet? IMHO, i dont really have any need for an overdrive section. but a nice furry glow at the more extreme settings of a gain knob would be nice to have.

also, a nice pad would be helpful, cause my Sadowsky can really kick out the jams, if i'm not careful.
 
#198
jokerjkny said:
omfg,

that will SO RAWK. :hyper: :bassist: :cool:

basstasters be dammed, this amp'll be makin' some UNREAL clips o' joy!

and has the "overdrive" been decided yet? IMHO, i dont really have any need for an overdrive section. but a nice furry glow at the more extreme settings of a gain knob would be nice to have.
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I'm thinking that you're right. If you want a little OD in your tone, run in on 100W mode and crank it.

also, a nice pad would be helpful, cause my Sadowsky can really kick out the jams, if i'm not careful.
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I'll have two inputs jacks:

#1 - Passive/Active (low output)
#2 - Active (high output)
 
#200
jokerjkny said:
sounds good, B,

and someone correct me if i'm wrong, but i thought power amp overdrive, even if its tube power amp overdrive, isnt gonna be good for my cab's speakers.
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Good question. I'll be honest and say that I'm not really sure about this one. Perhaps someone with more experience can chime in and provide the answer to this question. I can see how it might be a bad thing at high power levels, but since I'm not sure, I'll say I don't know.

I know that for guitar amps, say a 100W Marshall for instance, they live all day at high volume and at high SPL's, so it makes me think that the speaker power rating is the big issue here. ALTHOUGH low frequencies might have a completely different effect than the mid-to-high range of the guitar.

:help:
 
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