Reverb

[-CB-]

If you generally just CLONE the Fender circuit, transformer, tank, and all, what you'll end up with is a working reverb.

At that point, some tweakage to the input cap the the "send amp" (12AT7).  You can try one, then another... You'll hear what works best pretty easily.

Then, the mixing... the 3.3 is "supposed" to be standard, but... at 3.3megohms, you can try say... 3.0 and 2.7 for more drive.  If the reverb gets wimpy... increase it a bit.  Similarly, if the channel is too heavy handed in drive, crank that resistor up a tiny bit to say 3.6 or even 4.7megohm.  The 10pf is a guide - you can try 10pf, or NO cap, or 22pf or 27 or 12 or 14pf if you can find them.  Its not critical, you just a/b compare the two channels "dry" and if one is too bright thats one place to even it out.  Since the resistor is so big, you only need a very small capacitor to get the "bypass" effect and let more highs through.  <-- similarly the ESR is quite important.  Going silver-mica to ceramic will result in big tone differences, even though the cap values are the same.  Silver-mica is very low ESR, lets highs pass more easily than ceramics.

 

[Patrick from Davis]

Excellent.  Then I have a plan and will eventually have something to mess with.  The next question, or set of questions...  The Accutronics Type 9 Reverb tank is a long 6 spring unit, (three springs made of two opposite wound springs connected together for mechanical reasons, they say)  There are three decay times that are available.  Short (1.2 - 2.0 sec,) med (1.75 - 3.0 sec,) and Long (2.75 - 4.0 sec.)  Do you have a suggestion on which will be closest to a Fender unit?  I did a half assed search and there seems to be a couple of opinions on this.  I was curious to hear what your opinion was.  Next is the output impedence.  They offer three options, and I read that the middle one (~2.5K) was similar to what was found in Fender units.  Any suggestions there?  What I want is what everybody wants, Reverb from Surf to Subtle, and perfect.  Heh heh heh.  Thanks again for all of the great info.
Patrick

 

[-CB-]

There's no real holy grail here on tanks.

You DO want 8-10 ohms input impedance.

IF you get the long delay, all you need to do... is put a pot on the grid of the 12AX7 (after the bypass cap) and it will act like a volume control for the signal that kicks the tanks springs, thus altering the delay.  The reverb control on a Fender amp is really a mix control.  It determines how much of a the reverb is mixed back into the dry signal.  On those amps, the reverb quality is preset, you just mix in more or less of it.

On the stand alone unit, you had the three controls:  Dwell, Mix and Tone.  Dwell is the volume control on the tank's input (volume control on the reverb send amp).  Mix is the volume control on the output of the reverb recovery amp.  Tone is a simple splitting type tone control that in that circuit for the overall tone of both the reverb and dry signals after they're mixed (I think... I dont think it just controls the wet signal... I could be wrong and its too late for me to lookup!).

Make sense tho?

 

[Patrick from Davis]

I get it.  You have a reverb decay (or strength of signal in), a Mix of dry and wet signal, and then a tone knob to knock off some of the highs if it gets too sparkley.  Makes sense.  On the Fender Super Reverb wiring diagram they use a 12AT7.  Any reasons to use a 12AX7 instead, or is it just an gain/output issue?  Hmmm, now just to find a way to afford all of the guitar stuff, pedal stuff, and the next amp stuff.  What fun it is to think about all of this stuff.
Patrick

 

[-CB-]

They use a 12AT7 ...and notice... both halves of it too... because you're asking it to deliver a lot of current to drive that output transformer (and thus the tank).

Based on that.... there was an idea in my head... to run four 12AT7's in push pull..... with a 12AX7 as the front end and a small interstage transformer to do the phase splitting.... no tone,  just a volume control, and maybe... an ungodly little 1/2 watt amp.  Just an idea.  Powered in an unusual way by taking wall warts apart...  but... right now, just an idea.

 

[Patrick from Davis]

Give ZVex's Nano amp a run for it's money then...  Fun.  I wonder how much square footage, err, inches that would require.
Patrick

 

[Tonar8352]

I think this is the best Stand-Alone Reverb unit in the world. Of course that is my opinion and it is extremely bias. Uncle Spot!  Yea Ron!!!!!!!
http://www.unclespot.com/USreverbunit.html

 

[RLW]

Holy moly, is that YOUR ES350T???

I'm guessing, I think that's what it is...

 

[Tonar8352]

Yes, good eye!.  1959, same year my wife was born.  A very good year!!!!!!

 

[-CB-]

Uncle Spot... aka Ron the Pervert ~ <ggg>  I gotta catch back up with him

 

[Rick]

The thing is, while there is certainly better tone in a reverb unit, for most applications, a pedal will work fine and it fits in a gig bag.  I know, this is blasphemy, but I had to say it. arty07:

 

[Patrick from Davis]

That is true in some respects.  A modeling set up that does a good job of imitating what ever sounds you are going for is probably the most useful live.  The audience rarely can tell, and that is only if you have a good sound guy.  But, if you can have it as a part of the set up in the first place, you might as well put the good stuff in there.  I know that this post started by asking about which pedal folks like best, but...  Also, if you can build yourself an amp that just makes the sounds you like in the first place, then the pedals are not really needed.  I had to ask because there is not much info on the nuts and bolts of the reverb units.  A lot of the time people expect you to decipher the schematic and have a eureka moment.  I don't have the background to do that.  Now I know more, and am scheming of a way to get all of the doohickey's, whatchamahcallit's, and thingamuhjig's to build an amp that suits me.  With a tube powered long three spring reverb tank for poops and giggles.  Just typing that puts a grin on my face.
Patrick

 

[vanhagar]

So I'm guessing I could probably install a reverb in my vavle Jr head, that would be cool ! How would I do this?

 

[-CB-]

Go buy the smallest size reverb pedal you can find.  Somehow hide it in the head.  Find/beg/borrow/steal/create a power supply from the amps electronics to power the pedal.  Run the foot switch "remote", run the control(s) onto the amp head.  Thats as good as you can do, as.... you arm has no room for the two extra tubes, circuitry and extra driver transformer, insufficient existing power transformer to handle the extra tubes, and is too small for the tank as well.

 

[vanhagar]

I need a better amp  :sad:

 

[Patrick from Davis]

Oddly enough, this showed up in a catalog about a day ago...

http://guitars.musiciansfriend.com/product/Fender-Vintage-Reissue-63-Reverb-Amp?sku=480553

I am sure it is nice, but I'd get a used Hot Rod Deluxe, and make a couple of mods to get the amp as well as the reverb for the same price.  If you do have to get a pedal, I am sure that either that you listed will be fine.  It is hard to tell is one is better if you cannot put them side to side.  That being said, when you put a pedal reverb next to a tube reverb, it is noticeable.  And that starts the process of acquiring new gear.  If you then figure out what to do to modify things, then start reading this darn interweb, well in the end you end up with some very nice interesting things and no disposable cash.
Patrick