Hi Synda,
That does not seem like it's working correctly,
If you purchased it NEW then just take it straight back to the place of purchase.
Check another G3 amp and see if it does the same thing,,, if so they may work that way.
If it's faulty then The shop will likely just swap it over for another.
Hope it pans out for you,, Phil.

Hello checco,
                   I've had great success with this one it may interest you.
http://www.ssguitar.com/index.php?topic=1136.0
I take it you wish to DIY a circuit?

Cheers Phil.

Hi Bjorn,
         Great to hear that someone benefits from all my years of frustration.
Learning to use a simulator put me way ahead of where I was heading and certainly helped to understand what goes on inside the world of electronic amplification.

Re the PhAbbTone, Yes the mid full OFF will deliver the deep notch.
I tend to use the mid at 9 o'clock as full off really bites into the bandwidth and starts
to rob the sound as a whole. If you have a *Parametric* tone circuit you can achieve a similar tone shape but IME my tone box is darn hard to beat.

Re your setup looks good,, maybe insert a graphic *After* the CabSim before the HPhone Amp. Don't be afraid of using 2 graphics ,,even one after the other.

Simulate some of the old valve circuits and plot the response curves.
At every point the curve alters by small or large amounts, depending on where you poke.(Sims make light work of it all)

It then stands to simple reason that to recreate Valve tone, tone shaping becomes *very* important. It's very hard to recreate the half wave clip of triodes but thankfully it's not that important. Power tube compression is what you want and thankfully that CAN be recreated with reasonable results.

My thoughts on Cab sim. well I've found that the Marshall shape after a distortion
unit is the most useful as you can get the fender'ish sound via preamp tone shaping
anyway.  You will hardly notice any missing extended range because the graphic will pull it back up if needed.

IME A good fender Valve amp cranked up will tend to loose treble anyway as do marshall's it's just more noticeable in a Valve Marshall. (Different output tubes)
I'm speaking about the old circuits not the modern higain stuff which I'm afraid have
lost the plot. IMO most are just clangorous noise makers and a few are just plain
unusable.

If you want build 2 sim circuits and switch between them but out of all the guitar
players I've helped 9 out of 10 want the modern rock sound anyway which
has more marshall colour / flavour anyway.

The hardest part to overcome then becomes the distortion itself.
I built dozens of dist boxes using multitudes of different ideas but alas if only I could
see past my stumbling block *the tone IS part of the dist*.

Yes every tube screamer (TS9) circuit or similar has a high pass filter in front and low
pass after the diodes but trying to do it all with one opamp package is close to
impossible. The basic TS type ciruit is pretty close but just lacks the extra EQ or a
CabSim.
-----
IMPORTANT side note:
A TS9 into a good tube amp sounds ok but when used into SS amps they can leave you wanting. So with SS you need a cab sim after distortion as SS power stages usually have miles to much bandwidth so they tend to be very harsh.
Remember a valve powerstage also runs through a transformer and the Tr wipes off
a lot of high freq hash. (close to perfect setup) But with SS no such luck as all the hash is passed onto your speaker so unless you want to design your own transformer coupled SS poweramp it's back to cab sims and EQ and some tweaking.
-----

With my DDC I opted to use the same input setup as the original Nobels I just added an extra pot to aid in the touch response effect.
I think the mistake that is often made with these circuits is the assumption of having a
big high impeadence input, which is just copying a triode setup but a triode may have
200VDC to work from. OOps! sadly your little opamp often only works from a small DC
voltage. At 10 to 20VDC it's A big ask.
There are places to use high value resistors in low voltage circuitry,,this is NOT the
place.

Big input imp gives big bandwidth, allows bigger AC signal swing, all of which become
discarded so why make it hard when there is no need.
A 100k input is all you need here. Throw in a 1meg resistor and you get more of
everything, noise, potential feedback, harder to control the dynamic response of the
diode clipper,, So I opted to stay with original Nobels input setup.

If I need more crunch I just use a simple Fet booster pedal to make the input signal
bigger forcing the diodes to clip a little harder so the whole circuit responds much more like a real tube amp would.
Bear in mind I do own and use Valve Amps so I do know what's happening.

Well enough talk;  here is my DDC circuit to give you some ideas to work on.
The original circuit can be found on *Nobels* site *SST1* but you might have to dig for it as this is a very old unit now. It's rather complex as the SST1 came with chorus
and delay and multi input selector, I only wanted the dist section and the cab sim.
It came with a rather poor attempt at compression which was like most compressors was a dud. These things just kill any dynamic response and make any guitar sound like a processor. IMO, Great in a studio but destroy guitar signals.

I've noted some of the changes I made on my schemo.
Took me ages to back engineer this thing and build a new one as the original was stuffing up and hardly worked.
Later I got onto the internet and found the schematic actually existed.
Darn All that work and it was sitting on the net the whole time.

I should state one tecky nitpick; The output really needs a buffer stage
but I don't find it a problem in use and it also meant another opamp so I scapped it.
It will be sensitive to the impeadece of what it's plugged into, ideally it needs to look into a high imp.

Build my tone box and the DDC and the rest is cheap stuff and a few odd bits.
Cheers, Phil.

Quote from: kikey on December 08, 2009, 06:08:45 AM
Maybe this link will give input for people trying to simulate classic amps:
http://www.harmony-central.com/Guitar/guitar-amp-evolution.html

Yes interesting but it does not impart a simple straight forward explanation of tone.

Mutiple gain stages sound like a free ticket to Mass Distortion. 0:)
when done without any understanding of the *TONE SHAPING* that Also has to happen for it to work successfully the end result is often an amp that is a flop.

When I ask Players how they like there Big Name, multi channel, hi gain rock monster rig the answer is mostly like this;
"I just ended up useing the clean channel and I use floor unit/pedals to get all the other sounds."

Take the early Peavy 5150 it's a joke as it has a 10Db noise penalty in the effect loop,,,and that is present even if you don't use the EFX loop. :duh

I Fixed A laney ???something 30 watt recently; The Hot channel had so much hiss and hum that it rendered that channel unuseable. And that was a brand new Amp. :duh

Some of the Amps I test in the shops now are a complete joke. And I'm Talking the Big Brands as well as the SEAsian/China import copys. :duh

Plugged my simple tone box into a rather *boring* HotRod De'ville a few weeks back,,,
*THEN* it did sound like a REAL fender!!! 0:)

My2Cents, Phil.

Hello kikey,
              I guess it depends on what you are trying to achieve, what kind of music
hence tone you want and importantly ,,*What gear you are running it all through*.

My emphisis is on *Live playing* so your needs are bound to be different if you are wishing to record guitar, So I'll just speak of my live setup.
No doubt some of this may give you ideas for recording setups.

I have two main setups, One utilizes a tube poweramp the other is all SS.
I stay with the SS setup as I assume you wish to work with SS.

For SS I first plug through my (PhAbbTone box) >> then a (Dynamic Distortion Control)
>> Then through a HiFi Graphic EQ >> then whatever Amp I feel the need to use on the day.
Mainly a 30watt SS Laney KB with basic Treble and Bass for final tweak.
(Yes it's a keyboard amp of all things so squeaky clean, no fancy guitar tweaked circuitry in this one, which is what you want for this idea to work well.)

The *PhAbbTone* is my own idea and it dramatically improves all the amps I've ever
plugged into, (including my Valve gear).

Go here; http://www.ssguitar.com/index.php?topic=1136.0 

Down the bottom of that page is a graph, now have a look at the mid cut in Db,,,
Now compare the Db on the HeXe page. I doubt you will find any that produce a 35Db cut in the midrange frequency.

Remember all these cab sims are active whereas mine is a simple passive input tone stack.

If you want all mid fuzz just bypass the tone box and tweak the graphic.
if you want the more modern sound then PhAbbtone switched on.

The DDC is just a fancy name for a dist unit with a cab sim built in which is loosely based on a very old circuit from a *Nobels SST* headphone unit which has a cab sim built in so I just tweaked it for live use.
I've made it much more dynamic so as to reproduce the classic rattle that old tube amps get (even when they are clean). Any fuzz box can do full on distortion but much harder to reproduce all the in between rattles, so yeah Works a treat.

DDC On it's own it's kinda average without the Graphic or the Tone Box.
but add tone shaping *Before and After* the *Dist and CabSim* then it's a whole new world of tone. 
I kid you not,,,You are talking about a NIGHT AnD DAY Difference in sound/tone/dynamics 0:)

The Graphic is just a second hand old Tandy one about 30 years old.
you just drill the back to mount 6.5 guitar jacks and bypass the pathetic RCA's
BTW Don't use the Boss GE7 pedal for this, it's a dud.

So hopefully you can now see I'm trying to get folks to see the basic concept is
DEAD Simple.        **EQ,Distortion,EQ**.
You can put my phabbtone box in front of most distortion units (Pedal, Rack or Amp mounted) and a Graphic after it and get quite stunning results.

When I try to impart the simplicity of this to frustrated young players I'm quite sure
they think I'm nuts, but nail down some fundermental tone shapes and it becomes quite easy to grasp.

So generally speaking you need about 4 basic tone shapes.
A Big fender tone is a big dip at 300/400Hz,, the bigger the dip the bigger it will sound. (The steeper the notch the better it sounds,, shallow dips don't sound covincing). Hence my PhAbbTone does killer fender tone.

British sound is more Mid high the classic Marshall mid Honk as some refer it.
Cutting everything above 3 to 4KHz.

Modern Higain rock is kinda tricky but I get that by dipping the mid at 400Hz (PhAbbTone) and cutting the 1KHz on the graphic, the shape is sorta like a fender twin tone shape *before* dist then a tweed tone shape *after* distortion.
A Brilliant combination sound,, I love it. <3)

Metal, pull down a lot of mid band and big bass boost at 100/200Hz.
You can pulloff the Mark Knopfler sweet stuff but the valve setup tends to work better for that.

If you think I'm the only crazy nut that thinks in this manner then have a read of this page. http://www.amptone.com/truesecretofamptone.htm
Sorry,, All text so make a coffee and absorb the pure simplicity,,not that hard,,no maths involved. :tu:

So in answer to your question;
"phatt, in what situations do you get problems with these circuits?"
On there own they only produce average results,, but in combination with a well thought out setup. Great idea.

Others will have other ideas and thoughts on all this and I have no doubt there are many roads will lead to the same end but I'm just stating my experience with all this and I've not spent a $fortune$ in the process.
I have access to more sounds than most top line gear but at a fraction of cost.

Have fun with it all,
Phil.

Hi kikey,
            They are not a one hit wonder but yes with some thought they can help.
Look closely at the amount of CUT in Db those curves show.

One curve in one place *May not work* you often need multiple stages of EQ and you have to know where to insert them.

I've built 4 of the JTM simulator and sold them mainly to folks in recording situations.
JTM circuit Live they can be a pain to work with you need to insert them *After* distortion effects.

That unit worked well after my old Quadraverb when I was recording but I use a completely different circuit live.

If you are going live forget speaker impedence curves and all the fancy stuff you need to EQ.
If you need more info just ask.
Phil.

OK thanks,
             
I'll assume you have read all the pros and cons while using *Attenuators* on tube amps.
When just used to turn down the speaker volume they are rather limiting as they do tend to kill off the dynamics of the sound.

You just need an Attenuator which is a special pot used in crossover units to balance the sound.
They can handle a 5 watt amp with ease but make sure you wire them up the right way.

When you get frustrated with the limitations of Attenuators alone then you might want to go the whole way and *Reamplifiy*
your simple tube amp whould then have access to a lot more options.

Well that's what I've done and I struggle when I have to use normal amps.

Meanwhile have a long read of this and find out how the pros get around all this mindnumbing confusing issue.

All text but if you read it you will understand that when looked into with some common sense logic it's dead easy to get stunning tone with even simple inexpensive gear.
http://www.amptone.com/truesecretofamptone.htm
Have fun Phil.

YES it can be done, the concept is not new as the idea was thought of a long time ago.

Attenuators are actually the poormans way to do such things but if you want to think outside the box you can be greatly rewarded with a setup that will be hard to beat for the outlay of basic equipment.

I've spent 10 years trying out different ways to do these tricks so I know what works and what does not.

Before I go futher I need a discription of the amp and approx wattage might help
otherwise we will all get lost.
Phil.
EDIT; sorry I don't know what a nano is.

Try here,
             http://www.stocklogic.com/nohum/

Chris Kinman site might have comments on the subject also.

I don't know what other countries use but in Australia we have *Earth Leakage protection* units. (ELP)
Which are now law in new buildings but you can also purchase them as a portable unit.
Even with these it's still not a 100% protection.
Phil.

Quote from: madapj on December 02, 2009, 09:22:57 AM

I saw also, in the ESP page that is used another "little" bridge with a resistor and a capacitor in parallel to prevent loop. (Figure 3 - power supply) from http://sound.westhost.com/project27.htm.
My question is, i have to use it

No you don't have to use it Rod E is just covering all possible situations that his circuits may have to confront.
You will only need it with really big complex setups.

Re the .1 ohm resistor hanging off the speaker you mention.
Again NO. Until you become more confident with building just leave it out.

I my experience it only makes a very subtle difference to the end result,, but hey others claim great benifit. It gets many names ,, (Defined Impedence or Current Feedback)

From 18-0-18 secondary you should get at least 22watts.

Re elektronika circuit,,,play with different values for C1, I'd try lower even .5uF, but let your ears work it out.

Now back to PSU I posted, the problem you now face is those 680 Ohm dropping resistors will need to be changed.
You will need to mess around but at a guess ,, 470 Ohms might be a starting point.

Don't worry your english is obviously good enough to get the point across
I very much doubt I could write it all down in your language.

Arrh,, just noticed your post JMF,, thanks it all helps.
Yes bread board or protoboard EVERYTHING.
I've learnt that the hard way but it was all so long ago I forget to say it now.

Have fun with it Marco,,you will learn as you go,, Phil.

OK lets get a few things sorted,,
I assume you wish to follow the ESP P27 preamp BUT use an LM3886 poweramp chip?

I've never been interested in chip amps and quite frankly using two transformer windings with two Bridge rectifiers to drive a single or dual 60 watt amp is just plain insane overkill.
If you where building a 400watt RMS @8 ohms power amp then YES it's worth the extra effort and expense.

Most of these poweramp chips can run a single supply rail but dual supply generally gives better perfomance.

Now unless I'm mistaken the red PSU board from *Chipamp* does not join the *Common pcb track* right at the Main Filter Caps. From what I've read this is poor design.

Side note; Thank *Teemu* for pointing out that hidden gotcha on PSU filter caps:). It had not dawned on me until I read his book. Good on yah Teemu

Sounds like you should download teemu's PDF book and take the time to read it as it may help you come to terms with building an amp. The link can be found right here on SSGA.

Sadly all the overrating of parts is probably going to waste if you don't have good pcb layout.

Reading right off the Data sheet,
LM3886 is rated at 50 watts RMS @ 8 ohms from a 50 volt CT Tr delivering 35-0-35VDC.

Now the psu for ESP's P27 which states a 150 VA rating on a 50 volt CT secondary is
driving a 100watt amp,,  Humm, then I'd say it's perfectly capable of driving a little LM3886 to full output and beyond.

I'm not the chip amp expert here but a quick look at the workings tells me this chip uses all NPN output drivers which from what I understand is well out dated being that use of
both N and P drivers is now commonly accepted as being better.

I'm adding a small schematic to help get your head around the power supply.
this should power most small chip amps like you propose and deliver a split rail for preamps.
Cheers, Phil.

Hi madapj,
              http://sound.westhost.com/project27.htm
The Preamp Power Supply is derived from the main Voltage rails of P27.
Shown (though not clear for beguiners) at the bottom left of the preamp schematic.
(R18 R19)

The 680 ohm resistors will run quite warm,, I suggest 5watt will run very cool.
The Zener Diodes clamp the voltages to 15VDC.
Simple ,, works quite well, though If you want better than this you need to use Reg chips,, but more complicated.
Phil.

Quote from: Zappacat on December 01, 2009, 03:27:47 AM
Thank you very much.  I keep seeing this thing called chip points on the forum while browsing through posts.  If I could award you one I would.  I just don't know how.  Can someone please tell me how to award chip points on here?  I owe a huge debt of gratitude to so many people on here.  Can someone please tell me what's up with this?

See where it says; (informative/ useless),,, Clicking the on the word will up that members chips.

I don't know if *Useless* subtracts any points though. LOL.
Phil.

Hi madapj,
              Please note the error on the link.
Page 4 schematic 1/3 (The PSU)
I have not read it all but this one seemed rather obvious,
The negitive rail as drawn is back to front and
WILL lead to confusion for those starting out.

I believe it should look like this, see pic.

The 47uf cap sets the roll off for low frequency,, try between 5uF and 10uF.
50uF will only be needed for bass guitar, or disco doof.

http://www.ssguitar.com/index.php?topic=1136.0
If you want a preamp with no distortion,, and it will then actually sound like a guitar amplifier.
Phil.







 

Hi billyjoe,
I'll assume your use of the word *Gain* means some kind of OD/distortion?
That big fat rich OD is coming from the power stage not preamp triodes.
Triodes are only doing voltage amplification/ Voltage gain.

Generally they only do halfwave clip which aids the powerstage fatness a bit but without additional circuitry,,, No big fat distortion comes from them.
The whole point of tube amps is power stage compression without that you will be eternally frustrated.

You can build a no frills EL84 amp with 2x AX7 and 2x EL84 with all the gain you will ever
need,, just by refining the *POWER STAGE*.
Maximising the compression effect *Inside the powerstage* is the secret to success.

In the words of King TUT; "If you want MAX tubyness then simple cathode biased amps are for you."  All the bigger stuff is much harder (READ $$$$) to get it to happen.

I personally went round in a big complex multi triode preamp circle and now I use one of the first tube amps I ever built.
a very simple cathode biased amp. (2 knobs,, volume and tone.) 
ALL the rest is done via external mostly SS little trick circuits I've built.
When I do need extra volume I just take a speaker line out to a second 120watt SS poweramp and a big quad box.
This negates all the needless complexity and expense of big tube amps.

I play at a local muso club and I'm competing with Cyber twins, Carvin legacy's and the
manditory Fender devilles. I have no problems pulling all the needed tones of a good guitar rig. If truth where known I think it pains them moreso because they know I'm also using a $150 stock chinese strat copy. 

The master volume era was created so one could overdrive the input and adjust the master to lower level. Although it may seem like a logical step it's conterproductive as it kills off the magic of the power stage. That's why you don't split valve preamps from valve power stages with things like efx loops or SS reverb loops as you break the magic bond between the preamp and poweramp. SS amps are completely different so fine do what ever you want but tube amps work best as one complete unit.


My learning is thus; **Little amps always sound sweeter**,
because by design the amp spends more time in *Powertube Compression* mode.
in a nut shell;
The bigger and stronger the power stage the harder it gets to make magic as the bigger amps have to run a lot louder before they compress and the power supply sags.
You fight an endless circle constantly adjusting between preamp dist and master volume.
some big fenders run so clean you may as well be using SS.

Re heaters;
Don't worry bout that for now as you are obviously considering gutting this amp and if you start out with a simple EL84 powerd Ceriatone kit you won't ever have to concern yourself with needless complexity of DC heaters.

Re gutting the amp.
The trinity hiwatt uses 6v6 or kt66 so not even close, different tubes give different
sound/tone/feel/dynamics. but hey if it's well thought out it might be just the ticket.

Get this one nailed on your list of things worth knowing It may help unravell some
confusion when discussing power valves.

TC (transconductance) in simple terms *Gain*
(the most over used word in the amplifier world)

TC of common guitar power tubes,
(Tetrodes verses Pentodes)
T 6V6 TC= 3,800
T 6L6 TC= 8,000

P EL84 TC= 11,000 (apprx)
P EL34 TC= 11,200

Armed only with that info even a novice can now see why the term,
"British sound verses American sound" comes from.
The Type of output tube makes a big difference to the end result.

An EL84 only needs a 30 volt swing on it's grid to go full output whereas a 6V6 needs about 70 volts swing. (I think a KT88 needs 90 odd volts on the grid)

Now that does not mean that a 6V6 can't produce good distortion but you have to know how to build an output stage and know the tubes you are using.

The Tone stack in the SA412 it the best you'll get and you can build it as a stand alone unit if you wish and take it with you to any amp.
Read my blab under Schematics and layouts
http://www.ssguitar.com/index.php?topic=1136.0

Keep in mind a big part of Hiwatt sound is due to the use of *FANE* Speakers

Some homework;
Try Valve wizard pages,, Tone Lizard site (go to the tone lounge for some good grounding in Valve gear.

Have fun Phil.