Crazy Verb Idea

WesKuhnley · Post by **WesKuhnley** » Sun 04/29/07 2:51 pm

I'm going to have to chime in on the old analog vs. digi discussion. I do alot of studio work, obviously build guitar amps, build studio gear (my day job is working for Great River Electronics...) including mics, pres, and Spring reverb units. I've been known to throw a HG into my box before a gig when I'm playing an amp without reverb, but in any giving situation I'm in, stage, studio, engineering, I always prefer spring verb (or when tracking drums, tube driven plate verb) to digital. Not that digital verb doesn't sound good, especially Lexicon 480L and PCM 42 delay...but I feel like analog verb feels more natural, has some dynamic transient response that makes it smoother than digital. Most of the time in the studio I'll set up a speaker or a guitar amp in the live room and put a mic 50 feet away to create my main vocal and piano verbs.

I guess the deciding factor is always application. The arguement could also be made that in a gig situation, most guys won't even hear the differance, or care if they do. Bottom line is, use what gets the job done, if that's a HG, or if you're lugging around an Echoplex and '63 Fender reverb unit, whatever floats your boat. My boyancy is provided by 19" long springs and a 6K6...

tarzanalog · Post by **tarzanalog** » Sun 04/29/07 4:43 pm

WesKuhnley wrote:My boyancy is provided by 19" long springs and a 6K6...

Excerpt from Neil Young interview:

JO: What effects do you use the most?

NY: An original tube Echoplex, an MXR analog delay, a Boss flanger, and an old white Fender reverb unit with new springs that are separate. The springs are on a microphone stand that goes on the cement floor of the building. It extends up to the bottom of the stage, and the spring stands on top of the microphone stand and the wire comes through a hole in the stage completely separate. I can't use it if I don't do that, because if I jump onstage, the spring rattles. It has to be isolated from the surface of anything that's vibrating.

JO: What if you can't drill a hole in the stage?

NY: No, we do it. We just put a hole in the stage. There's always a way. It can't be very far away, because with a long wire, you lose the fidelity, the high end where the reverb lives, so the magic is gone. You've got to keep it close and really short.

Whole interview here:

http://www.thrasherswheat.org/ptma/equip.htm

phsyconoodler · Post by **phsyconoodler** » Sun 04/29/07 4:55 pm

It's really hard to argue with guys who are playing amps with reverb and have done so since the early sixties.
All the horror stories you have about 13' of cables and reliability issues are just as prevalent with digital stuff.How many solid state amps have survived from the late fifties to today?Not near as many as tube amps.
How many tube driven reverb amps are unrepairable?None.
If you want to put digital reverb in your amps go for it.But to say spring reverb is unreliable and noisy is just not so.
I guess I kind of see that digital reverb in your amps would be inovative and give sounds different from the old school.To tell you the truth,I don't even use reverb when I play on stage.I use the room to provide the natural reverb.If I need reverb in a recording I can get the engineer to add it at the board.I like reverb when I'm playing at home,but I am not a good enough musician to use it successfully on stage.Some guys are.I would say 90% of those guys use spring reverb.I could be wrong,but if they like tubes,chances are they prefer spring reverb over digital.
Why not build a digital modelling amp? OOps! line 6 did that.Who wants a line 6 here?I bet no one.
The real trouble I see with grafting digital stuff into a tube amp is the voltages.You could just install the Holy Grail into the chassis,shield it and have a relay or op-amp for switching it in and out of the loop or the input.Use a foot control to operate the on/off feature.

s2 · Post by s2 » Sun 04/29/07 9:54 pm

"But to say spring reverb is unreliable and noisy is just not so."

I challenge you to put your oscilloscope where your mouth is or at least put some theory behind your statement.

Or, quite simply, turn the reverb knob up to 5 on any amp with verb and listen to the noise floor increase 10dB or more. To say that spring verb does not add noise to a circuit is simply unsupportable. You can't add signal length and gain stages to a circuit without increasing its noise floor. Granted, I'm absolutely anal about noise in amps. Probably much more so than is healthy ;)

As for reliability, take a survey of amp techs asking what their most common repair is. I suspect you will find reverb to be #2 or #3.

I guess I'm going to abandon this idea. If I can't get a group of tinkerers on board, I'm certainly not going to get players to go along.

I just think it is a crying shame to perpetuate what was a (IMHO) lousy solution to a problem (marketing wanted a feature) and let it dictate how we design amps today. It is still my very strong opinion that great sounding amps don't need reverb. How many of you guys are rushing to put verb in your 18Watters?!

zarfnober · Post by **zarfnober** » Sun 04/29/07 11:12 pm

Dick Dale hangs his original fender unit from the cieling with a rope! Seems to eliminate all of the problems associated with vibration from the amp, stage, etc. He's on tour, best damn reverb you'll ever hear. Maybe Neil should try this trick.

Rocco

seancostello · Post by **seancostello** » Sun 04/29/07 11:43 pm

http://www.spinsemi.com

The FV-1 is a digital reverb chip, with built-in ADC, DAC, and delay memory. All you need to use it is a 32kHz watch crystal, a switch for selecting presets (if desired), up to 3 pots for adjusting parameters, and some way of adapting the surface mount chip to DIP, plus some stable voltage source.

If you want to get fancier, you can program your own algorithms, and select them via an external ROM. The built-in algorithms sound EXCELLENT, as far as digital reverbs go - most of the reverbs are designed by Keith Barr (founder of MXR and Alesis) and follow the basic topology used by Lexicon.

$10 for the chip in single quantities.

Sean Costello

phsyconoodler · Post by **phsyconoodler** » Mon 04/30/07 1:37 am

s2,
Ok,I guess I should correct my statement." reverb does not add noise to an amp".An acceptable amount of noise.You said yourself you are anal about noise.If you want digital reverb find a way to do it.If you want it without noise,good luck.
How quiet do you need an amp to be?And why do they have to be so quiet?Do you play it or sit and listen to it idle?
And reverb repairs are low on the repair list.

d95err · Post by **d95err** » Mon 04/30/07 5:09 am

I'd recommend checking out the reverb noice gate circuit described in Kevin O'Connor's "The Ultimate Tone". It's a simple circuit and should be completely unintrusive to the amp and reverb sound.

It uses a FET to shunt the reverb recovery stage output to ground when there is no reverb signal. The circuit taps into the reverb transformer primary to get a the control signal.

I haven't tried it myself yet, but when I buld an amp with reverb, I'll definately add it.

s2 · Post by s2 » Mon 04/30/07 7:08 am

seancostello wrote:http://www.spinsemi.com

The FV-1 is a digital reverb chip, with built-in ADC, DAC, and delay memory. All you need to use it is a 32kHz watch crystal, a switch for selecting presets (if desired), up to 3 pots for adjusting parameters, and some way of adapting the surface mount chip to DIP, plus some stable voltage source.

If you want to get fancier, you can program your own algorithms, and select them via an external ROM. The built-in algorithms sound EXCELLENT, as far as digital reverbs go - most of the reverbs are designed by Keith Barr (founder of MXR and Alesis) and follow the basic topology used by Lexicon.

$10 for the chip in single quantities.

Sean Costello

Well, I'll certainly be checking that out. If not for this, then for something else. I've been looking for a chip like that for a long time!

s2 · Post by s2 » Mon 04/30/07 7:21 am

"How quiet do you need an amp to be?And why do they have to be so quiet?Do you play it or sit and listen to it idle? "

So quiet you can't tell it's on until you hit a chord. Why? Studio work. A lot of guys are taking these into the studio lately, and I want the reputation of building the quietest amp on the market. It's already quiet, but I won't be satisfied until it is SILENT.

WesKuhnley · Post by **WesKuhnley** » Mon 04/30/07 8:12 am

Good luck with that one.

tarzanalog · Post by **tarzanalog** » Mon 04/30/07 8:35 am

s2 wrote: Well, I'll certainly be checking that out. If not for this, then for something else. I've been looking for a chip like that for a long time!

Steve,

If you get really creative with the FV-1 you might be able to use one of the onboard LFOs (it has FOUR) to modulate some of the delay lengths, dramatically reducing the ringing tail sound that I (and many others) despise about digital reverb. THEN you'd really be onto something.

s2 · Post by s2 » Mon 04/30/07 10:28 am

WesKuhnley wrote:Good luck with that one. :roll:

Thanks! I've already done it several times. Just not with this particular model.

seancostello · Post by **seancostello** » Mon 04/30/07 12:12 pm

tarzanalog wrote: If you get really creative with the FV-1 you might be able to use one of the onboard LFOs (it has FOUR) to modulate some of the delay lengths, dramatically reducing the ringing tail sound that I (and many others) despise about digital reverb. THEN you'd really be onto something.

Most of the reverb examples for the FV-1 use the LFO's. The 2 sine/cos LFOs are used in the bigger hall and plate reverb algorithms (to modulate 4 of the delay lines in the recursive "tank'), and do a nice job of reducing ringing. The interpolation used is linear, which results in some loss of the high end, but since the interpolated delays are within allpass networks, some of the highs still come through in the feedforward path.

I've been designing digital reverb algorithms since 1998, and the ones that are publically available for the FV-1 are the best I have ever seen published. Very similar to what Dattorro published in the 1997 JAES, but with more variety of design.

Sean Costello

tarzanalog · Post by **tarzanalog** » Mon 04/30/07 12:34 pm

Thanks Sean... good to know!

s2 · Post by s2 » Mon 04/30/07 6:26 pm

OK, I've orderd 5 of these chips for tinkering. See! It will be a compromise solution. Tube buffered DSP. Should be GREAT!!! At least I hope. I'll let you know how it turns out.

WarrenH · Post by **WarrenH** » Mon 04/30/07 8:20 pm

Has anybody tried the T-REX Room Mate reverb pedal?

It has a tube in it and is supposed to sound really good with no springs. Maybe you could incorporate something like this into your amps.

I like a little reverb when I am playing in small dead-sounding rooms.

phsyconoodler · Post by **phsyconoodler** » Mon 04/30/07 8:34 pm

s2,
I owe you an apology.All you really wanted was someone to help you install a digital reverb system and myself and others got carried away with our love of spring reverb.
I usually get on this forum when I am overtired and tend to get a little carried away.

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