70s Circuit Vid

[Billion81]

Hey Folks-

Ted here. I finally shot and edited my first Vid. This is a 100 watt 70s circuit built by a Private Builder..

This was more of a How does it all work/sound type vid..See how turned out..

Anyway- I think the 70s circuit is really unique and frankly the best Clean amp of the bunch..the PAB on this thing is almost like a SLO but even more wool on the tone.

Anyway- Killer amp..Hope y'all dig..

http://www.youtube.com/watch?v=bs1nW3--DVc

[Structo]

Sounds really good Ted!

I love when you crank the OD on the Strat.

Sounds like it works great with a strat, something my ODS has trouble with.

Who built it?

[bluesfendermanblues]

+1 what exactly is the layout of that amp - its sounds really great - and add here to a Maple neck strat

Ted you've got a fan - great playin'

[Billion81]

Thanks guys-

Tom- I sent you a PM on the builder..

I really like this circuit for Single Coils. My 50 watt Double Trouble is also based on this (70s) circuit and it really rips too. I hope to start shooting and editing a vid with that amp as well as I think Bill does some really cool stuff with his builds.

My 80s Skyliner (Bludo) did NOT do well with Single Coils at all. that said, the Zingaro which is also an 80s Sky voicing sounds awesome so.

It's actually a pretty low gain amp on the regular OD (non PAB mode) which I really like. The cranked gain tone is from the PAB with the Contour knob dimed.

bluesfendermanblues-

Man, I wish I was smarter about all the intricacies of this circuit (or any of them). I probably don't meet the tech IQ to be on here at all..I'm such a goof on the technical nature of this stuff.

What I do know is that it's a 70s Layout/Circuit- with adjustable FET and a Contour knob which the builder put on the rear..I pretty much keep that dimed.

I used ultra short cable runs to keep the highs up for including the 'lator.

That's a older EJ Strat- It's a mess, Frets are toast- input jack is barely screwed in. I love it though..finally starting to get some wear on the neck and FB too. that nitro finish is like Pine Tar..

Thanks again for the kind words..

[ElectronAvalanche]

Hi Ted,

Great playing!!! and wonderful sounding amp!

Since I recently built one of these 70s monsters, I wonder if you couldgive a bit more info on which layout schemo used? Is it a Seperate Master Hybrid?

Bright switch on or off?

How do you like the Treble Pot Taper? And the Bass pot taper?

Thanks again for this great video!

Keep em coming!

Cheers,

Electron

[ER]

Thanks Ted! Tasty all around, nice to hear some chords on a demo too.

Say, is that a lap steel case on the couch? (hint hint) I would love to hear that amp with some slide...

I echo the others on more topology info.

-ER

[Structo]

I'm curious about the Contour control, I have seen it on Two Rock amps.
What is it and how is it implemented?

[Billion81]

Oh no..More tech questions-

Electron-- I do think this is a Hybrid. MK will hopefully chime in @ some point.

It does have a separate (not global) Master, so more like a traditional Skyliner layout.

Bright Switch off on the Amp. but I do have the low Bright (or Bright 1) engaged on the 'lator.

I like the taper pots but note that I tend to keep everything @ noon on my rigs including this one..

The mid/deep switch is really subtle on this circuit-

Bill= Bill Dunham who runs Sebago Sound. He built an amazing 50 watt 70s amp but with KT77s and some other cool tweaks..That amp is really cool too. clips coming on that one.

ER- Yeah- I got asked awhile ago to bring the chord stuff in..The case you see is my strat case..It would be cool to run a Lapper with that amp..I'll grab one from our studio and see what I can come up with.

That amp just sings with my Tele as it has really glassy and powerful barden pups.

[M Fowler]

Amp sounded great and very good playing Ted.

Mark

[ElectronAvalanche]

Hi Ted,

thanks for all your answers!

What is that swtich you flip at 2.08? Starve switch? Since the volume does not change that much, I guess it is not a starve switch??!?!

Do you have a pic of your amp outside? Maybe even inside?

Thanks again for that great video! I really think that there should be more 70s style amps and videos of these amps out.

These things are monsters!

Cheers,

Electron

[tubedogsmith]

That's one of mine. It's pretty much '70's circuit. 100k plates, 1.5k/5uf cathodes. It's got a mid boost though. It looks like Ted's plugged into the FET input, the gain control for that is on the back. The presence control is on the back as well, I think that's maybe what Ted's calling contour, it may be marked that way. The OD channel switch and PAB switch are on the front. The small knob added at the far right is the clean master, seperate masters. The pots are probably a mix of the different generations. the phase inverter is setup for a 12AT7 like the blackface Fenders. the OD circuit is the old style, 3 resistor with one bypass cap. All four V1 and V2 grid resistors are 68k. Precision power supply.

The first couple of these I built started as pretty stock circuits and then got tweaked to taste. By the time I did Ted's it started with what I know I like and then tweaked some more. Ted can make an amp sing for sure.
Here's a pic, I'm not sure this is the same amp but if not it's close enough for rock-n-roll.

[tubedogsmith]

I'm curious about the Contour control, I have seen it on Two Rock amps.
What is it and how is it implemented?

tom, the 2rock contour control is a vox style cut control.

[Billion81]

What is that swtich you flip at 2.08? Starve switch? Since the volume does not change that much, I guess it is not a starve switch??!?!

Check it out..MK in the house with some proper tech answers...

ETron-

That's the manual PAB that I hit where all that sick ass gain and wool comes on.

I agree that this amp needs to get some exploration. I'm keen to do some clips with the 335 and you will hear how magically delicious the cleans are..

the low wind A2 shaw pickups on my 335 allow me to bring in the high Bright on the 'lator and the thing just sings..

The OD side is different when you first play it..Gary (Johnson) correctly notes the "Fizz" on his web site with respect to this circuit. This is the kind of fizz you want though..Once you sort out this tone it really is a great rock tone..

Sort of like my Wreck amps- when you hit the PAB I really have to have my shit together as it is VERY in your face so all clams are magnified by an Order of Magnitude....Hence I rarely use the PAB.

[ElectronAvalanche]

Hey Tubedogsmith,

thanks for your reply and informations. Nice amp btw!

I find the Mid-Boost is one of the secret ingredients to the 70s. I have two options on my amp:

Boosted: 2200pF

or

286pF or 520pF

I tend to go with the 2200pF most often, but the 520pF gets used as well.

The FET is mandatory in these amps IMHO. When I built my first Dumble style amp (preamp back then) in 2001 I figured I would never need the FET. How wrong I was.

BTW: Gary's suggestion using a 470pF cap paralleled to the 1M is right on the money on the FET. Flattens out the sound quite nicely.

I am still undecided whether to implement the Starve switch (see schematic of #004 for this) in my 70s amp. Just for kicks. When I played the real deal I found the Starve switch quite musical but the volume was dropped significantly.

Maybe Max can chime in with his experience with the Starve switch since he knows that amp pretty well I guess.

I definitely need to try the 70s preamp into the Power amp of the blackface era circuits and see how much influence the Power section really has. I am even tempted to mod my HRM into a 70s.

@Billion81:

I immediatly felt at home with the OD of my 70s. Maybe it is my playing style, but the later ODS are not enough Rock'n'Roll for me. The 70s will probably sit nicely in a band context (still need to test my amp with the band).

There is something very interesting going on with the presence and high mids in the 70s that the "newer" style amps do not have. Very Marshallesque, but with a much better "distortion". Where the Marshall Overdrive/distortion can get grain, the Dumble has an overdrive on sustained notes that simply fades away and does not get grainy.

Thanks again for the vid (Billion81) and pics and info (tubedogsmith).

Cheers,

Electron

P.S.: oh and btw: is that a Thai chassis? looks different from the CE.

[boldaslove6789]

Sounds great Barks and sings all @ the same time! Nice guy shot's too, looks like a steller amp. The playing is very Jimmy Herring ish...