Hi SChrome,
                You have no gain block only a filter which is lossy by nature.

Take a look at the Tonebrake, the 2nd stage is where all the gain happens.
Without that it's worse than a passive setup
Phil.

Hi Mr Fahey,
                 Well you certainly leave no stone unturned. 

In this digital age where every kind of effect known is accessed via a simple press of a button it might be sobering for some of the younger ones to realise how much work was involved just to make *one effect*.

Ouch! Bakin the ferrite just to form the mag is obviously no simple deal and it is the hardest part to source when they break.

I find that once the fine wire that passes through the magnet snaps off it's curtains unless you have an old tank laying around.
I always salvage any kind of spring tank (working or not) just to get those damn little magnets,, hopefully with the wire end bit still intact.

Thanks for the insight into the finer details.
Phil.

I don't have a Pod handy but I doubt a passive setup could even come close to what the above circuit (or Similar) can do.

I'm only offering advice having been there done all that,,if you catch my drift? 8|
Phil.

Quote from: J M Fahey on July 28, 2010, 01:39:08 AM
Yesterday I bought some 1.5x5mm perforated cylindric magnets ... you can imagine what for ...
Haven't made a reverb in ages; besides last year I lost all my dies (don't ask), but I think I can improvise some.
Let's see what comes out of this. :duh :loco

Wow!  So you want to make the Tank from scratch?

Humm? I think you you need medication.

Just kidding you    You are brave, an I wish you luck.
Phil.

hi Shinnychrome,
               Once you grasp what is needed I doubt you will have any need for adjustable stuff.

Once the toneshape is created the rest can be done with simple stuff.

ToneBrake circuit;
I built 6 of these some years back and sold all bar 1 unit which I still have.
This one worked wonders after my old Quadraverb unit.
Worked best in a recording situation. Most of the big name rack stuff will benifit greatly when recoring.

On clean sounds it's hardly inspiring,, but gezz once you get into heavy OD's it really becomes obvious.
You need to insert this **AFTER** Dist or raky gear, not before.

I found this thing to be a great learning tool ,,not only for the electronics but you start to realise just how critical tone shaping is.
As one chap stated with eyes wide open after using it for some recordings.
"WOw I never realised just how much Hi Freq crap just destroys good guitar tracks,
an that magic box cleans up the mess".
This chap owned Masses of expensive recording gear BTW.
Needless to say he asked me to build one for him.
One thing I would change (Now that I've learnt a little more) is the output really needs a buffer.

If you wish for more things to look at check my Schmo page here;
http://www.ssguitar.com/index.php?topic=1648.0
The *DDC* there is both an OD unit and Cab sim all in one neat little circuit,
though a little more complex.
Cast an eye over the PhAbbTone circuit ,,delivers up to 30Db notch cut @ 400Hz  

One thing you might find useful is wedging in a simple Graphic EQ after the Cab sim.
This will give you access to many of the sounds you may wish to nail.
GEQ without the Cabsim box *first* will not be as convincing.

GEQ before cab sim will help but I've found it much simpler to run an old fashioned passive EQ stage before dist/OD >> then Cab sim >> then GEQ.

Truth is there are just so many ways to do it and some will be better than others but for me the home made equipment I've assembled/ collected over the last 10 years is all basically cheap and simple gear.

I personally refuse to lay down big money on gear that is often only marginally better than what I've built for very little outlay.

BTW I'm not alone in this manner of thinking as there are many pages on this at Amptone;

Try starting here; http://www.amptone.com/index.html#eqconcepts

It will take forever to read,, ALLLL TEXT (sorry no fancy stuff) and I must say hard to keep track of,
a little too wordy in places but a 100 ideas to give you insight as to how to approach things.


Heres' a little snippit I took the liberty of lifting for you.
________
EQ concepts and pre-distortion EQ
John Murphy, chief engineer for Carvin Corp., wrote "the pre-clipping frequency equalization and post-clipping EQ are absolutely critical adjustments. Once you have a well-behaved clipper -- even if it's just simple diodes, as in the stomp boxes -- it is the precise combination of pre- and post-clipping EQ that mostly determines how an amp sounds. The 'secret' of the best sounding guitar amps lies in the pre-clipping EQ response curve."

Van Halen's guitar tech recommends an EQ pedal above all, as the most valuable pedal, in his book Guitar Gear 411: Guitar Tech to the Stars Answers Your Gear Questions, pp. 75-76.
________

Now I'll just add this to give you a head start;
The trick is NOT about making the BEST tone circuit (i.e. I've just built the best EQ circuit on the planet)
and expecting it to deliver gold.

The best results will be found in a combiation of different circuits and shapes.
What you hear from the speaker is combination of many shapes all imparting their particular alteration to the sound produced.

Hence my simplemans approach is old styled passive tone in front> Dist> Cab sim> GEQ > Main Amp.
Have Fun,, Phil.

Hi shinychrome0,
I'll take a stab here,
I'll bet it worked on the sim and you assumed it would work in real life.

*** Be very aware Sims are not bullet proof ***
Quite often they give a result that might look really good on screen but
in real life are impossible.
Very powerful tool but can easy lull a novice into a false sense of security.

You do need to do some homework and read up so that you have a reasonable idea of *basic circuit function*.

I'm saying this because Like You I was learning and making these kinds of mistakes not to many years back. Be patient, Google the terms you read so that you develop a solid basic circuit understanding.
(And of course ask these wonderful chaps who've posted above me as they are a treasure trove of knowledge :tu:)

As has already been said the circuit is way off and there are much easier ways to achieve what you wish.

I'll also assume you are trying to get a very sharp rolloff?
If so then Google  *Ed Rembold Marshall Simulator*
(Ed's circuit is a simlified version  found in Marshall JTM Amp schematics)

Or hunt down the *LXh2 cab sim* stuff.

LXH2 is complex but Ed's sim is about as easy as it gets and it does it's job well.

If you wish I will post my Marshall Cab sim circuit for you to work with,
you can even tweak some of the values to your liking on screen to see how each part changes the rolloff.

At least you know it will actually work when you put it together!
Phil.

Quote from: ohmy!! on August 06, 2010, 08:12:05 AM
Yeah, I tried plugging a wire between the effects send and return.  It doesn't do anything different.  I'm going to get a hold of Peavey later today to get a schematic from them. I know the effects loop was working properly

*****because I can plug the preamp out on the XXL into the poweramp in on my VTX
and play it and ran some effects in the effects loop on the XXL.***** 

Q? DID You Get Sound from Speaker in XXL Amp?

IF you did get sound,,,, then highly likely one of those 2 loops (yeah the ones you Forgot to mention) Is broken/malfunctioning.
Then try direct (Working) Cable in "BOTH LOOPS"

ps.. Please please try and stick to the Amp in need of repair
Otherwise it can get extremely confuzzing for those trying to help you.
Remember we don't have your Amp/Amps in front of us. 8|
Phil.

Hi ohmy,
            Hazata guess try the efx loop trick.
i.e. Loop a lead from Efxout to return.
just fixed an early Peavey special last week (has the auto tranny like yours)
the loop switch contacts where shot.

If no luck then Go with Enzo's thoughts,, You need to establish a Real connection to the power amp output.
if it's like the one I worked on then several switches/ connections happen between poweramp out and speaker.
Phil.

Hi trialabc,
               Yes in basic terms they are the same thing, BUT (Always a but)
In bacis terms, Reverb is just very short delay/Echos and Echo is long delay times.

Reverberation of say a big Hall has multiple (usually short) delayed returns and they all tend to mass together. Also consider each one may have returned after being bounced of different surfaces and hence each path returns a slightly different sonic/tonal siganture.

Just check out the specs of your computers sound card and see how Reverbs can be played with to deliver different sound enviroments,, i.e. cave, bathroom, hall.

For the purpose of guitar the spring tank has been the most successful for adding colour to the sound.

Delay is more like standing between two mountains and a loud call will return a long delay of what you yell, often returning a complete phrase a good 1 or 2 seconds later.

For guitar,, digital reverbs and delays deliver outstanding broard freq response and it is debateable as to whether this is good or bad. (depends what you play also)

To much digital stuff can make you guitar sound ,,well TOO Perfect and this can lead to a lot of frustration. You might wish to ask the chaps that have gone back to some of the analog gear which although limited tends to be more realistic.

For me ,, I've never muched liked the Digital Reverb sound so I use a Spring tank for Reverb but often add a Digital delay for some songs.
Have fun, Phil.

Hi,
    Agree with JMF,, You folks need to get out more it's called Google. :lmao:

It's a HiZ Tank.

For Accutronics Tank *4FB2A1A*
Drive Z = 1.5k
PU Z = 2.2k

If you get a DC reading of around 200 Ohms with a DMM then you are close enough.
(likely a similar DC reading from both transducers)

Any Tank close to that will work just fine.
Be aware that some of these rev circuits are nothing special.

Here is how to to make a REAL Reverb circuit.
http://sound.westhost.com/articles/reverb.htm

I think I'm actually partly the reason for this Page as I kept hassling Rod Elliot for more DRIVE as most circuits are gutless at the drive ability.

Rod was a great help to me in my endless struggle to build a decent Reverb circuit.
Have fun, Phil.

Hi jordy,
             Don't loose sleep it's not an exact science.
As long as the drive end is close to 600 Z.
A DMM Reading should be around 50 to 80 Ohms DC will get you in the zone.

If you want to chase the harder stuff you might find some good reading here.
http://roymal.tripod.com/accutron.htm
Down the bottom is all the rev tanks ,,given in both Z and DCR.
The output (pickup side) transducer can be anywhere above 100 Ohms DC and it will work fine with that circuit.

You might want to consider the reality that the rev circuit in that schematic is not the greatest and an outboard unit might simplify construction and reap far better results anyway.
Having spent far to many years frustrated by onboard rev setups I built my own stand alone unit which is all SS and works like magic.
The beauty of an out-board Rev unit is you can take the reverb signature to *Any other Amp* you use.
Phil.

Hi mate,
Yes you can use the uA741 or similar,, just remember the pinout is different.
Ask Jaycar for a couple of LM833 dual opamps,, these are technically far better than 741 but really it won't matter much while you are breadboarding stuff.

You may find the 741 (being a single unit) are easier to work with while breadboarding.
You can setup a split power supply just with 2 x 9V batteries in series.
The mid point between them becoming the *Common or Ground* refference.

Use LM833 or TL072 when you build the PCB though.
Phil.

Hi Dogbox,
              Preamp for LM3886 is here;
http://www.ssguitar.com/index.php?topic=1672.0
Halfway down page.

Have a look at the gut shoots on my last posting on there, might give you some ideas of how you might build it all.
The hand drawn pcb preamp board should be rather obvious and although the main board looks complex it's only the centre bit that is used. All the rest is disconnected or removed as that is the sub circuitry and remote sense stuff.

Oh you poor man if you have to endure *Beenleigh* as it's just an extention of brisbane now.

I moved from Brisbane to get away from the stupidity of the big city it has become.
My Uncle ran a pineapple plantation (years back) at Woombye (Near the big pineapple picture shown) so I knew this area well from my youth.

Now I live here, an I love the country town feel.
Phil

Thanks for the interest JMF,

The Dingo couldn't make it but the Possum had good jam on Sunday. 

Sadly the hard hitting Wombat drummer turned up and He was just a little to much for the subwoofer possum amp.
(LM3886 through a 6 inch Speaker).

Not to worry a good experiment and it's all still quite useful.

One day I might be tempted to make a whole new Poweramp board and rebuild it all into a small Amp.
(I do have a 10" Guitar driver somewhere in my junk box)

also will have to look at rebuilding partly because Now that I've mounted the input socket to the Metal Back Panel that power cord has no EARTH 
so the Metal panel really needs to be Earthed to be Safe.

Meantime here's a few pictures of the internal bits.
Phil.

Hi Enzo Thanks for the explaination of the vastly complex.

But ya know One can't help but think Geezz that's about the most complex way around a simple problem?
Phil.