Author Topic: 25-50WPC Stereo Tube Power Amp for Guitar Rig (PC) setup? (Read 2418 times)

Randyman... · « **on:** January 05, 2011, 06:24:40 PM »

My guitar player runs a hybrid amp rig with a small Marshall Master Lead Combo (12"/30w SS Combo) and also runs a DI into a Computer running Guitar Rig and/or Amplitube modeling plug-ins - which then feeds one channel of a Peavey CS800X power amp into a Marshall 1960B 4x12" cabinet.

Obviously - the Peavey CS800X works fine and is PLENTY loud - but I'd like to get him something better - like a Stereo Tube Amplifier with around 25-50 WPC (preferably 50WPC to help keep the clean patches clean). Balanced XLR Inputs are preferred as the computer's DAC output is a good 30' from the power amp.

Are there any DIY projects along these lines that a newer DIY'er could tackle?

If not a Stereo Tube power amp - what about something a bit more "musical" than a Solid State PA Power Amp like I'm using now (the CS800X)? Maybe a descent solid state amp with less NFB/lower damping factor like most guitar amps would behave? I'd really prefer a simple Tube power amp solution - but I haven't found anything aside from full-blown guitar amps with a single power amp channel (I just want to build a stereo power amp - no Tone Stack, no Pre/Post gain, no EFX loop, just a stereo power amp). A DIY Mesa 20/20 or 50/50 type power amp would be sublime :-)

Thanks for any pointers/links in the right direction!

andrew_k · « **Reply #1 on:** January 05, 2011, 11:07:26 PM »

Take phase inverter and power amp from a known-good clean guitar amp (eg: HiWatt DR-100, but with only 2 output bottles for ~50W), hang a suitable transformer off the input for balanced to unbalanced duties. Done.
Might need a generic 12AX7 gain stage up front to really drive the phase inverter. One 12AX7 will give you one triode for each channel.
Practically any power supply suitable for a 4x octal bottle (eg el34, kt88) will be suitable for your 50WPC amp.

Randyman... · « **Reply #2 on:** January 05, 2011, 11:22:10 PM »

Are any PCB's/BOM's available for such a project? I'm really not all that well versed in frankensteining stuff on breadboards - and with such high voltage potential it is intimidating. And I haven't done any PCB Etching in all my years. Getting a more involved "Guitar Amp" PCB and not populating the preamp/EQ on it would be fine with me - and even using two for stereo might be an option.

Point to Point might be an option if it is fairly simple wiring - but I'd need a friendly "shove" in the correct (noob) direction. I was hoping more for a kit (as I duck for cover!) - but the only kits I see are for Hi-Fi type amps - or for full blown mono Guitar Amp/Preamp type units. I'd prefer to modify a currently available kit (at least a PCB) versus trying to whip something up from a schematic and some point-to-point wiring...

Thanks for your expert input!

Maybe a used tube power amp would be a safer (but more expensive) bet?

andrew_k · « **Reply #3 on:** January 05, 2011, 11:53:41 PM »

- My input is not "expert" by any stretch of the imagination. You're welcome, none the less.
- PCB for a tube guitar amp? Turrets or eyelets are a far more simple option.

I recommend you build something from AX84.com, such as the stand-alone 20W or 50W power amps - http://www.ax84.com/corepoweramps.html
Double the power transformer requirements so it can power both channels.
20WPC would be plenty for most situations, otherwise your friend still has his SS amp if he needs big clean decibels. They have good documentation and a helpful community in the forum.
you get BOM, schematic, and turret board + chassis drilling templates.

Randyman... · « **Reply #4 on:** January 05, 2011, 11:54:55 PM »

Scratch that - I just dove in on a Marshall 9005 50W x2 for a pretty good deal. Now I'll need to balance those inputs

Thanks for your input regardless

I'll still have a peek at the link you posted. Seems like a neat project.

abbey road d enfer · « **Reply #5 on:** January 06, 2011, 05:24:41 AM »

The whole point of amp simulation as offered by Amplitube and Guitar rig is to simulate electronically the power amp and speaker peculiarities; they are intended for reproduction on a clean uncoloured chain such as studio monitors or high quality PA.
Using it in conjunction with a tube amp and a Marsher 4x12 is like a bacon-cheese-chicken-fish-pork chop burger with BBQ-salsa-blue cheese-ranch-thousand islands sauce.

andrew_k · « **Reply #6 on:** January 06, 2011, 05:49:20 AM »

ok now I'm hungry

abbey road d enfer · « **Reply #7 on:** January 06, 2011, 06:10:12 AM »

Yeah, like I see these guys they put a Pod in front of their Hotrod Deluxe. The double helping of amp grit and speaker rattle, in addition to the reverb conflicting with the venue's acoustic environment so they have to crank it up louder just makes me go away...

riggler · « **Reply #8 on:** January 06, 2011, 08:24:40 AM »

Hey Randyman,

I have a nice ADA T100S stereo tube guitar amp for sale if you're interested! I don't play guitar. I used it for a few years as a listening amp for my stereo until I got this awesome oldschool Technics amplifier...

Randyman... · « **Reply #9 on:** January 06, 2011, 11:34:10 AM »

We're not using the Cabinet Simulators in Amplitube - just the Preamps and Effects. I guess we are getting 2x power amp "passes" (one modeled, one "real"). Regardless - we really like the sound of Amplitube through the 1960B 4x12 and the CS800x (cabinet sims disabled) - and we have a full blown 3500Watt PA to compare it to! It just needs some "mojo" as the CS800X is a bit steril and "stiff" on the 4x12" - and I think the tube power amp will do wonders.

If we had a Fender Twin - I might agree - but this is a power amp and cabinet. No tone stack, no reverb, no overdrive, etc.

Then we also have the "dry" Marshall Master Lead Combo (straight from guitar > DI Pass-Thru > Combo Amp - 100% analog chain) that we blend with Amplitube/4x12" for a very interesting pallette IMNSHO.

Thanks for your offer, riggler - but I think the Marshall 9005 I snapped up will do the trick

Off to work

microc · « **Reply #10 on:** January 06, 2011, 11:41:37 AM »

Please keep us updated on mods to the marshall =) This could be very fun!!

Good luck

alexc · « **Reply #11 on:** January 07, 2011, 06:01:36 PM »

I use guitar rig all the time in parallel to my guitar amp.

A feed in to my daw for recording and out to a stereo 20W tube amp with hifi speakers.
The hifi speakers make all the difference. You get the top end which I think is required
for digital effects emulation.

Sounds killer. The trad guitar tone is widened bigly by the spaced stereo speakers
and the tubes as always lend some weight to the sound.

Particularly if used with a foot pedal to swell in effects, like rotary.

This setup really made my playing experience much more 3D

Randyman... · « **Reply #12 on:** January 07, 2011, 06:53:41 PM »

Yes indeed. We will be using the 4x12" in stereo through Amplitube/Guitar Rig (cabinet sims disabled as that results in dull sound due to the high frequency roll off in the cab sim

). With the Cabinet Sims disabled - it sounds more like a real amp when played through a real guitar cabinet IMO. We tried running it through the PA system - but we didn't dig the sound. We are MUCH happier with the 1960B and a power amp (cab sims disabled) versus the 3500 Watt PA system with the cabinet sims enabled. You might open up a few more options with the cab sim and "Full range" speakers - but the guitar cabinet is just so "authentic" - and I'm expecting more of that with the Marshall 50WPC Tube Power Amp. Substitute the cab simulator for a real cabinet and "real" speaker rolloff and resonance and MOVE SOME AIR = better sound IMO...

I'm also planning on experimenting with EL34's and 6L6's - quite possibly running one channel of each in the Marshall 9005 amp. Should make the sound even more interesting IMO.

We also have a "Dry" fully analog channel from the Guitar to the DI "Thru", and into a Marshall Master Lead Combo (a 30W 12" Solid State open-back combo). The combination makes for some highly interesting tones combining in the air! We mic the combo and the 4x12" (2 mics on each) - as well as record the clean DI for endless possibilities in the mix...

All the non-believers should try it before blindly shunning the concept

There is a method to the madness (at least in my case - the POD into Fender HotRod scenario mentioned above is another story

)

alexc · « **Reply #13 on:** January 08, 2011, 06:36:24 AM »

Also stereo SE amps are cool for guitar.

I use a 7W per channel stereo SE 6L6 with some quite efficient 70's Sansui 12" hifi speakers.

Has a big sound with a clean 'crunch'.

Very usable in multi speaker/digital emulation combos

Won't compete with 3.5KW PA tho'

MagnetoSound · « **Reply #14 on:** January 08, 2011, 07:03:57 AM »

You know what sounds really great?

A guitar through a good amp.

Let your fingers do the talking.

(Yeah, I sound like my dad!)

alexc · « **Reply #15 on:** January 08, 2011, 08:40:15 AM »

You sure do!

Nothing wrong with a plain ol amp and guitar.

Nice and simple. Easy to comprehend.

Other people find experimenting with sonics interesting and find it leads to even better expression.

MagnetoSound · « **Reply #16 on:** January 08, 2011, 09:22:23 AM »

You're right, no offence meant. I've done it both ways too, of course. Been reading this thread with interest.

As you were ...

Randyman... · « **Reply #17 on:** January 08, 2011, 07:53:55 PM »

We do it both ways AT THE SAME TIME! The best of both worlds!

Believe me - my guitar player is all about setting the amp where he likes it - and letting his fingers make the sounds and dynamics flow (he loves the guitar's volume knob, too! - but mostly in the fingers). I wouldn't be his drummer for the last 20 years if he didn't have that kind of expressionism in his fingers

. I also loathe people that rely on the gear to sound like "them". My guitar player sounds like himself on any rig!

We use a straight analog connection from Guitar > DI "Thru" > a small Peavey MAX Preamp for some added gain on the Strat Single Coils (clean tube gain and some pre-EQ shaping) > a Marshall Master Lead Combo. That's an older 80's Marshall 12" 30Watt solid state combo that gets LOUD for its size and power (has a Celestion 12" G75 IIRC). This path is FULLY ANALOG and COMPLETELY DRY and the combo is miked with a 57 and an e609 into a Demeter VTMP2a. There's your "Real Amp" right there

We supplement with the Amplitube / Marshal 9005 (now a Peavey CS800x until the 9005 arrives) / 4x12" 1960B which is also mic'd with a 57 and a HM1. This is the "fun/wet" part of the rig - but generally just has a Hendrix Rotovibe type thing and a few different preamp models - nothing too fancy. The 1x12" Combo and the 4x12" are actually about the same volume at practice.

We also record the clean DI feed to a seperate track for endless options in the mix (re-amping, another Amplitube instance, a clean track to add clarity, whatever we need).

This works well because the guitar player also practices through Amplitube at home - so he can get a patch setup and bring it to practice and load it right up (he also runs a 4x12" at home, but a cheap Fender cabinet on my Sony TA-N55ES power amp).

I can't say I've seen to many rigs like this one. Many are FAR MORE complex - but not really any more versatile IMNSHO

MagnetoSound · « **Reply #18 on:** January 09, 2011, 06:58:38 AM »

Quote from: Randyman... on January 08, 2011, 07:53:55 PM

We use a straight analog connection from Guitar > DI "Thru" > a small Peavey MAX Preamp for some added gain on the Strat Single Coils (clean tube gain and some pre-EQ shaping) > a Marshall Master Lead Combo. That's an older 80's Marshall 12" 30Watt solid state combo that gets LOUD for its size and power (has a Celestion 12" G75 IIRC). This path is FULLY ANALOG and COMPLETELY DRY and the combo is miked with a 57 and an e609 into a Demeter VTMP2a. There's your "Real Amp" right there

FYI, the Master Lead 30 dates from the mid-70s. We used to use one in the punk band I was in back in 77.

As you say, the best of both worlds.

sahib · « **Reply #19 on:** January 09, 2011, 10:28:09 AM »

Quote from: Randyman... on January 08, 2011, 07:53:55 PM

....I wouldn't be his drummer for the last 20 years ....

That's a commitment and partnership. Respect.

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Author Topic: 25-50WPC Stereo Tube Power Amp for Guitar Rig (PC) setup? (Read 2418 times)