Two variacs for dummies...

[jnew]

It makes sense to me that there should be a difference. The power is being divided but instead of another cab moving more air, it's a dummy load that just robs some power from the 4X12 cab. And because the dummy is purely resistive and power always takes the path of least resistance, it stands to reason that a reactive load (the cab) may be less restrictive. So might explain why the cab see's more than half the power? Hell, IDK.

[Mr.Farva]

Is this right? Set the wall variac to 110-0 volts. But the cab variac has to be 90 volts or below?

[jnew]

Is this right? Set the wall variac to 110-0 volts. But the cab variac has to be 90 volts or below?

Dude, well done. Excellent illustration/pictorial on the set up.

The first variac is set to whatever works for you and your amp. There is a lot of room in this area to work with. We all know that a plexi plugged into the wall at 120VAC, biased to 70% and on 10 into a 4X12 is just crazy loud. But when you use a variac and decrease the input VAC to the head, the volume will go down. The bias also goes colder and is part of the reason why it gets quieter. So for example, if you lower the variac to say 90VAC and bias again to 70%, guess what? Your amp is pretty loud again. That's because a properly biased tube wants to put out it's rated wattage within designed frequency range with certain sensitivities and efficiency, and so on so forth. There are others here who could really give the breakdown on tube operation cause and effects but I'm only speaking on what I've realized through my own trials and builds. And remember that all amps are different. Power transformers vary greatly and plate voltages play a major role in all this. Ralle has targeted plate voltages at around 460 for his optimal tone. David has talked about targeting heater voltages for optimal tone. So as I mentioned earlier, there is ALOT that can be played with here. All that having been said, I now bias my amp to 70% dissipation with the amp on 110VAC. Now I can drop the varaic to around 90 and I get a volume reduction to play and enjoy more reasonably. Before, I had the variac at 90VAC but still bias'd at 70%. It was still loud as hell, which is why I re-amp'd through a Peavey Classic 50/50, tube power amp.

So along comes the 2nd variac trick. BAM. My tone world has changed. I don't want to re-amp anymore because this 2nd variac between head and cab is (IMO) the missing link. So I went and revisited the 1st variac and bias and all that stuff. I suggest everyone does. There's a lot there. The 2nd variac set at 90 seems to be unity in terms of volume. As if the speaker cable went straight to the cab. But the tone is colored whereby the lows get creamy rich, tight and punchy and well dialed (for lack of better words). The mids and highs come to life with glitz, fire and detail (so many damn adjectives over the years, I don't know how to explain it anymore ) Hormonic badass bliss So 90 is where I set my 2nd variac. I once lowered it to 70 just to see what any differences were and it does get a little quieter but not very much. That's why I don't like to think of it much as an attenuator but if you're just a hair too loud in any given situation, I suppose it could help. But 90 is what was suggested to me and that just works for me.

[JiMB]

Interesting stuff here, guys, thanks for the diagram, too!

[plexified]

You guys did a great job with the illustration here and James the tone is stellar. Like I said before you actually exceeded the raw tracks on the fair warning album! The Duncan Custom with the ceramic mag is awesome . If you find it hard just run with the Custom Custom with the AII mag. Still some nice goods their . If you have some flub on the bass the JB is right their too. Just drop it down a bit.
The coolest thing is we found these 'stories' actually work and sound great and are really safe when done right. In my case , I found a shimmer and swelling sustain that was just grail like. I'm sorry if I called Glen or Star Guitar , Greg , to correct that .
Cooter had messed with some suggestions I had with using a closed back cab open and with only two of the four speakers connected where you had two speakers as 'radiators' helping the bottom thump a bit and driving higher wattage speakers more where they can take it. Like Celestion Vintage thirties and such . The front or back throw does matter more in open back cabs though. Even if its your four twelve cab like Duane Allman used to do. Its just some stuff to test that may sound good. One thing is this stuff is working with the feedback loop and the communication between your output transformer and the speakers and the cone control. Its a big deal getting the right thump or 'bloom' in a note. One more reason to rethink that 'polarity' switch on the old amps. Instead of ac , its the front or rear cone throw to be clear. Even the simple resistor in the feedback loop and tuning it to get the right 'thump' is a fun experiment. You can really find a lot of tone in this one simple area. Gain , sizzle , thump and even frequency response really opens up here . Cheers to all that have taken the time to tune in turn up and git their smile on here . Sounds so good for sure.

[jnew]

GRAIL LIKE. That's it. That's the best description. And yes, I was just e-mailing someone about the same subject of it being all about how the head and cab are interacting with one another. And this is where the 2nd variac absolutely shines. The best result is the head having the reactivity of a breathing cab. For a long time, I re-amp'd with really pleasing results but the game has changed now. At least for me.

I remember trying the custom custom. Although I thought it was good, it stands out in my memory, as almost too smooth and sort of lackluster in dynamics. But that was a looonnnggg time ago with totally different amps and set up. I'm building a new guitar at the moment so maybe I'll throw one in and giver it another go.

So if a band had two guitar players and one had a Marshall, the other had a Fender, would there be some phase weirdness? I'm sure this has been the case before but never occurred to me tip now.

[FL6]

So all you have to do is cut the speaker cable, strip the +'s and -'s to the bare wire and bind them to those red and black binding post's. Keep the positives of the head and cab on the red post's and the negatives on the black post's and your phase will be proper. Although, you can switch this around and experiment as I did.

Do you run another +/- cable from those red posts to the input of the cab or is this for a 2 speaker jack amp?

[jnew]

I'm not able to understand the question. In the illustration above, the green line is a speaker cable from the head to the 2nd variac. One end will have a 1/4 inch plug that you plug into the speaker out from the head. The other end is stripped to bare wire and tightened down to the + and - binding post's labeled "IN" on the variac. Same goes for the yellow line in the illustration above. One end of a speaker cable has a 1/4 inch plug that plugs into the speaker cab. The other end is stripped to bare wire and tightened down to the + and - binding post's labeled "OUT" on the variac. Simple as that. Nothing to it.

[fhn_lopes]

Did you guys try using FX AFTER the second variac?? This could be the only con when comparing to reamping.

[dirtycooter]

Simple. Just tap the speaker line with your lineout box after the second variac before it hits the cab. Pick off the signal where its gone through the good stuff already and its not a big deal.
A lineout box built right will be totally undetectable by the main amp and completely transparent-what it sees is what it shrinks to line level output.

[jnew]

I don't know if you even need to do that. I think the interaction between the head and cab through the 2nd variac is the ticket to just use the other speaker out on the back of the head, for the line out. Would that not be the same signal? The dry cab is the reactive load. And it has been talked about how reactive loads make re-amping better and more dynamic. Well that should do it IMO. But, since I have another cab, a Peavey tube power amp and a line out box with a Jensen step down transformer, I'll give it a try. I'll put the dry cab out in the hallway and close the door. Then I'll re-amp through the Peavey and swap the 2nd variac in and out to the dry cab (out of the room so I don't hear it) and see if the re-amp'd tone is affected.

[plexified]

Hey ,
James that is a really good point. I guess short answer is , a Fender is a Fender and a Marshall is a Marshall and a lot of the two have shared the stage for decades . BUT , your totally right, their is possible phase regarding frequency going on and to that I guess experimentation to find a preference is in order when combined.
Regarding your tonal perception of the AII vs. the Ceramic in the Duncan , I would say spot on , you have some good ears to describe it that way. I embraced the 'filet mignon of tone' as described by RGalpin and using the .oo8 gauge burnished nickel strings I just beat the heck out of them to get attack or sharpness. It was a tonal challenge to work it to get it to sound harder or stinging here . But I still love the ceramic , its pretty huge. Not far away from a DD or DSD.
To think of you adding in the above described science approach of 'More' with the re amp is very intriguing for sure. Fun stuff. Are we adding to this tool box of tone or what. Can't find this stuff anywhere else. But great points regarding the injection of effects here.
I had my Zoom G9.2tt in the front end of the ol' 12er with vintage effects like a TS 808 and on and on in the Zoom loop with digital control over mix and placement and I was overwehelmed with possibilities. I was A/B ing vintage stomp boxes and the digital realm in the front end with unity input and on and on. It was stellar from that perspective with full control and programmability. No loss of options at this point. 'Ground control to Major James' , put your seatbelts on ....
P.S. I hear your writing an App for this , eh? Midi map your show set from your 'device' too much.
Hmm, what would Hendrix do? Imagine that, if he was still killin it and messin with this stuff.

[jnew]

I think the Duncan Custom is the Seymour Duncan answer to the DiMarzio Super Distortion. But the ceramic magnet used is not as big. And I think, for this reason, it's a little more user friendly in terms of being able to raise it closer to the strings, than I was able to do with the DSD and MM #1300. (MM #1300 is the MightyMite knock off of the DSD) I have both of those pickups and they are ridiculously close in tone, but have to be a fair distance from the strings or it just gets weird sounding. I attribute this to very big, or strong magnets. The Duncan Custom is a home run for me. A muscle headed PAF that doesn't need to be too far away.

Today, I intended to experiment re-amping, with the 2nd speaker out of the same head that goes through the 2nd variac to the cab, and then swap in and out the 2nd variac to realize any effects on the re-amp signal. But some vintage diodes showed up in the mail and I put them in my 100 watt Iskra/Mustard build and played with that thing all day. With this amp, I replaced the 100K with a 47K back in the NFB on the 8 ohm tap and put all 4 6CA7's in. Man is this killer but I gotta tell ya. There's this super tasty, raw, hairy looseness about the 100K in the NFB, that is just RIGHT, for lack of better words. To me, it just makes the amp spit this fire and rasp that is so authentic to early VH. Sure, the 47K gets tighter and a lot of people like that but when it comes to and open notes or chords, that 100K just really seems to hang it out there with the right STUFF. You guys ever try lifting one end of the NFB resistor and playing? Once again, David called this one out and I tried it years ago. Well, I got what that was all about real quick and it's a part of it. Big part IMO.

The other thing that remains a total mystery to me is VOL I. The 50 watter, which is the amp in recent clips, is at 5. That's it. Any more and it just saturates like shit and sounds like loud ass Marshall's from bands that didn't play single note rhythm stuff with punctuality and punch like VH tone does. And this 100 watter isn't much different. 3 or 4 on VOL I and it's growling. I just don't get the amp on 10 thing. Lots of distortion and sustain but just doesn't cut in and close the deal on the single note rhythm stuff. Ralle's amp is said to be on 10. That is truly unique to me.

Anyway, tomorrow I'll try to make some clips of the aforementioned, re-amp stuff.

[FL6]

I'm not able to understand the question. In the illustration above, the green line is a speaker cable from the head to the 2nd variac. One end will have a 1/4 inch plug that you plug into the speaker out from the head. The other end is stripped to bare wire and tightened down to the + and - binding post's labeled "IN" on the variac. Same goes for the yellow line in the illustration above. One end of a speaker cable has a 1/4 inch plug that plugs into the speaker cab. The other end is stripped to bare wire and tightened down to the + and - binding post's labeled "OUT" on the variac. Simple as that. Nothing to it.

Yeah sorry, I didn't see the above pic. Not sure how I missed it.

[Velva]

A little help please...

I understand how to hook up the variac if you have external binding posts. What if you are using an older Ohmite variac like the one pictured?

Can anyone with experience explain?