Still unsatisfied with your top end? Maybe another line to try!

A while back I posted some scuttlebutt concerning the Jay Mitchell rings which were offered a few years back as an aid to taming beaming.  They certainly do that in a way that no other device I have seen can, but we do not want to get into that argument here!  If anyone does want to discuss them in that context let's open a separate thread as it always gets - - - err - - - emotional?, - - - passionate? - - - partisan?  Well you know what I mean.

It occurred to me that one of the side issues with the rings is that, while their sole intended job is to reduce beaming, they do cause a slight darkening of the sound.  I have to point out that this is clearly predicted by the mathematics of their theory of operation.  They are gradually reducing the upper end effective diaphragm area to a 3" circle so some tilting towards the bottom end is inevitable.  Now, I've used the rings before with varying levels of overall satisfaction.  In every case they did just what they should and improved beaming, (when tested under best environmental conditions for that aspect, i.e. open air, absorbent ground covering, raised up, without nearby obstructions, for approximating far field listening without reflections), but some amps seem to be able to stand that tweaking of tone and some can't.

My old Valvetronix, a horizontal 2x12", wasn't completely happy about it.  Firstly, with the speakers side by side, it is impossible to improve beaming at all as the two sound sources are always going to produce the interference comb filtering that is the cause.  It was too bloody inconvenient to use an amp with the control complexity and layout of the AD120VT, exactly like an AC30 with 4x the controls, in a vertical alignment.  Also, with the modelling so well done, (the very early Vox Bluefaces were the best modelling amps I have ever heard bar none, the newer metal faces versions are - - - err - - - "disappointing" in comparison), the amp just didn't completely cope with the change to the well balanced root tones it produced.  When a tonal change is induced by electronic filtering it is easy to compensate with another electronic filter of the same characteristics.  Their slope is well predicted and repeatable.  When it is caused by something complex and acoustic, it isn't ever as easy as "just lift the top end back again with the treble control".  In our case there isn't even much of a treble control to do that with.  However.....

Having changed out my speakers from Vintage 30s to G12M Greenbacks and getting a huge improvement, then rolling the valves for JJs throughout for more, I was pretty pleased with the result.  The top end wasn't as aggressive, it seemed to be much milder.  But I still couldn't get rid of a slight niggly graininess up there which was easily heard when played alongside more conventional amp choices.  It's a bit like talking to a Geordie for 5 minutes then realising that he says everything 20dB above everyone else!  (And don't tell me I'm rascist, I'm a Geordie.)  For some musical types it will not be an issue, (the equivalent of talking to Gazza on a building site).  For my 70s classic rock, Free, Bad Company, Humble Pie, etc, it just got in the way from time to time.  Which is what led me to consider this little trick.

I still had the original foam rings lying around.  I don't need them for their beaming properties, but that darkening of the tone could be useful.  So I have just spent a half an hour fitting them to my pair of 1x12".  Oh boy!  The tonal change is instant.  It's not massively altered in its basic character as it doesn't kick in until the high area, the GM remains a GM which I would want, but it does just what I would have wished for at the top end.  All traces of aggression have vanished and a creaminess is now there when I set it up right.  I haven't lost all top end, just the tiny bit of glassy brittleness which is there.  I have an idea about why this seems to work too, but I'll keep that for later as this is turning into another tome of a post.

For anyone who is interested enough to go through the process of setting this up and trying it for themselves, all the details you need are in this thread on another forum site:

Mitchell Doughnut thread

Jay Mitchell, the guy who gave us this, has a real pedigree in the audio world.  He has posted this idea for free, with no products following it up to make money from.  You like the idea, you try it yourself, if it works he is happy for you!  He knows his onions like no one else in this field.  The thread is a great myth buster too.  There is so much hokum touted around in this area it is untrue, so the thread is a good read for anyone interested in how things actually work in a beaming context and why, (and why things don't work too!!!)

I warn you it runs to 45 pages long and has considerable "rant" info posted from critics.  You only need to read the first few pages to get the basic idea and design though, for the most part the rest is "Gee, your an acoustic God and we love you Jay", or "Burn the witch, burn the witch!"  Don't go all the way through it unless you like to read that sort of stuff.  If anything is not clear from the info there pop your problem in this thread and I'll clear it up for you.

It's cheap, requires only the minimum of materials, is relatively easy to fit, is easily completely reversible, and it works at least for me!  I can only use them at living room levels at the moment but all is very good under those conditions.  I am rehearsing tomorrow so will open them up then and I'll report back how well this works at higher powers and volumes.

this is golden. What a simple idea that may be just what many are looking for from this amp.

Thanks for posting this info Bordonbert!  I will have look-see when I get the chance.

My east-west doctor give me a shot of a homeopathic steroid in my left hand-little finger three weeks ago and it has dramatically helped with the pain!  I am able to play piano; finally, and next, if all goes well I may pick up the axe again!!!  

EXCELLENT news HwyStar!!!  I've followed your reports of your finger problem and was hoping that you would be able to give some good news soon.  Hope you're back with the rest of us, sipping tea in a dignified manner with neatly extended pinkie very soon.  I've got a suggestion that might help, a neatly fitting slide makes a wonderful splint   and it may just give you the impetus to try a bit of practice of that aspect of your playing without allowing you to stress the damaged digit.  Or follow the Django Reinhardt school just for a while and just keep on telling the world to fork off with the first two fingers of your left hand.    Patience!  You'll get there mate.  Mind you they do say "Patience is a virtue, possess it if you can. Seldom found in woman and never in a man".  At least, my wife says it!


This is going to be a clumsy post as I don't really have a fully crystallised picture of what I will talk about in my head yet.  Once you have a feel for ideas the words become clearer.  Let's at least see if I can make any sense of it.

I think there is a special aspect to this solution which makes it attack the problem on a different level to the others, and I think if that is true it might suggest other ways of improving things.  We've all talked and played with the speaker selection aspect and found this makes a huge difference.  We have messed around with valve changes and found that alters the sound.  We have now added EQ in the loop which definitely improves things a little more.  For at least some of us with perhaps less driving needs in the music we play, none of these seems to be capable of solving the problem absolutely fully.  I wondered if it was that a part of the nature of the problem couldn't be touched by any of these methods because of its origins and their place in the chain.  I have an idea that you can't fully compensate for a tonal problem using simple means by making changes before the point where the issue originates, particularly if it isn't an electronic issue that is causing it with its predictable poles and zeroes to duplicate in your solution.

I don't think that all of this brittle character is produced within the electronics, I think some of it comes from the iron, and it may even be that it is because the Tx is too good.  A lot of our guitar character is produced by trimming the bandwidth of the system to a specific fairly narrow range to emphasise the aspects we want to hear in an electric guitar.  The Bogner chesty sound is an example, as is the early valve Vox nasal quality.  Hifi is a different setup completely.  The bandwidth for a hifi amp needs to be the full audio range and a bit more at each end.  In a valve amp, one of the limiting components of the bandwidth is that output Tx.  That's why top class output Txs for hifi cost more than your mother and children would fetch at auction!  Despite what was suggested in a recent thread here, I wonder if the H&K output Tx is actually a bit too good, too wide a bandwidth device for the needs of the system.

You would think that having too much bandwidth would not make any difference to how a signal gets amplified and I would say that is true.  A thought experiment:  If I have a signal with a bandwidth of up to 3k and I amplify it moderately with two opamps, one with a bandwidth of 6k and the other of 60k, I will see virtually no difference to the signal output, bar a tiny tiny amount of distortion added which is certainly below hearing in any system as undemanding as a guitar one.  The distortions which are introduced are also related to the signal frequency content, they are harmonic and sound pleasant for the most part.  However, if I increase the signal to the point where the opamps themselves distort internally through overload, they now introduce high frequency distortions at a massive level which are characteristics of their own design and frequency ranges and not totally signal related, they include non-harmonic components and sound very different and unpleasant.  They also have different ranges of 6k and 60k.  These distortions will not be removable by simple pre-tweaking of the input signal.  They can be tamed by removing out of required bandwidth signal components after the point at which they are introduced, and that is why there are so many filters set up in an amplifier chain to keep the signal frequency content within the specified range.  a) Introduce some distortion in a stage, then b) Trim its high frequency content, is the usual approach taken.  But what happens if it is the final link in the chain and outside of the electronics of the amp?

We know that output Txs introduce their own distortion and it is a part of the valve character we want.  But if it is coming from a high quality transformer with a very high bandwidth capability then it will encompass that bandwidth in its own makeup.  Very high frequency distortion signals may well be introduced, even above the frequency of any real original content in the signal fed to the primary.  We will not be able to remove this from the original signal if those frequencies are not there in the first place.  For a very simple example, if the signal is a pure 200Hz sinewave and we introduce distortion at 6kHz, how could you remove that by introducing filters before the distortion generating stage?  There is no 6kHz content to reduce to compensate for that introduced as distortion.  The only way you could, would be to predict the distortion before it occurs and introduce a 6kHz signal 180deg out of phase with the distortion that hasn't even been introduced yet!  (Feed forward does exist but this is simple guitar amp stuff.)

I am honest when I admit I'm no ironwork guru but I know a couple of things.  Just slapping in a massive Tx does not do an amp any favours.  We know that cores saturate with heavy signal levels and this is a "bad thing" to allow in a number of ways.  However, having a Tx which is significantly bigger than needed may improve reliability of the Tx but it also introduces distortions and losses by the low field in the overly big core.  We know the 8-16ohms impedance range is unusual and hints of heavier ironwork to cope with the mismatch, and caution in the design of the output stage.  That in itself suggests to me the possibility of "big Tx distortion" mechanisms.

My idea is that the Mitchell rings allow us to do something unusual.  By reducing the effective radiating area for higher frequencies from 12" diameter to 3", a drop of potentially up to 16x, to improve beaming, we can also introduce a low pass filter, (albeit acoustic in nature), into the chain AFTER the output Tx and its unique distortion mechanisms thus putting a step down into the level of all high frequencies.  That way we would be taming those proposed overly high frequency components which I think the output Tx and maybe its associated output stage may be introducing.

Any suggestion of sense in that?

I should point out that I reserve the right to talk complete bollocks at any time!

And if there is any truth in this it has given me another idea as to how to address it........  

Bordonbert, I had to log in. Couldn't resist it. I read you swapped out the V30s for Greenbacks, and swapped out valves. i'm chuckling because friends have recently bought the amp and the 2xV30 H&K cab. They all comment about the top end. So glad I got the Jim Root Orange, voice of the world driver loaded 2x12. A vintage strat or tele played through is like having honey poured in one's ears, plus all the insane sounds with the high output guitars hooked up. No valve swaps, no driver swaps, no constantly craving something from an £800 amp that aint gonna happen without a whole load of faffing around. I am not criticising the cutting top end as some folk want that sound. Many don't and the simplest way to tame the beast is play it through a cabinet that delivers a sound which is pleasing to the owner. I like this forum but haven't been on here much because I've been busy happily playing through my Orange cabinet.

Hahaha! You and your Orange box. It'll go mouldy on you eventually, or you'll get a hankering for pears!

As you said, some folks want that bite in their top end and some folks don't. The thing is, I want to understand why the top end is so persistently letting you know it's there, and come up with a cheap and convenient way to tame it. Then, think about it, with the same speaker setup we have an amp that can be both a polite classy lady to take home to your parents and a rough old Portsmouth doxy you would want to introduce to your favourite uncle The potential is in there, I can feel it in my water. Oh! Oops! Errm, nurse...?

That said, I do hope your new found happiness with Nell Gwyn lasts.

Phrasemaker wrote:Bordonbert, I had to log in. Couldn't resist it. I read you swapped out the V30s for Greenbacks, and swapped out valves. i'm chuckling because friends have recently bought the amp and the 2xV30 H&K cab. They all comment about the top end. So glad I got the Jim Root Orange, voice of the world driver loaded 2x12. A vintage strat or tele played through is like having honey poured in one's ears, plus all the insane sounds with the high output guitars hooked up. No valve swaps, no driver swaps, no constantly craving something from an £800 amp that aint gonna happen without a whole load of faffing around. I am not criticising the cutting top end as some folk want that sound. Many don't and the simplest way to tame the beast is play it through a cabinet that delivers a sound which is pleasing to the owner. I like this forum but haven't been on here much because I've been busy happily playing through my Orange cabinet.

I`ve had a few amps that sounded better than the GM, the last being the Legacy III from Carvin (it`s got a beautifully dark tone to it and the cleans are unparalleled from any other brand). The only complaint I`ve had is that they are all pretty well one trick ponies. The versatility of the GM36 is above and beyond most anything else. If I can make some tweaks to it and get the sounds dialed in PLUS the convenience it will be really hard to top. As it is right now, I`m in three completely different bands with drastically different tone requirements. If I can use one amp for all three effectively, I call that a win

I know what you mean Jeff.  I'm strictly an amateur but the plight of the more serious players like yourself is a real one.  I know what you are going to say when I point this out but...  Have you ever considered modelling setups?  My own favourite amp before the GM was that Vox AD120VT I keep bleating on about.  It is, (not was), an awesome piece of kit, particularly once you know it and take care of a couple of simple weaknesses to improve long term reliability.  The second generation ones were at best very ordinary as the bean counters got in and the economies were made but the first generation Blueface series produced when the idea was new and interesting was second to none, and I tried them all out along with the usual valve names before buying.  It still stands head and shoulders above any recent modelling amp I have tried once you know how to get the best from it.  I think I'm right in saying that Vox had been taken over by Korg by that time, and they did the audio side while Korg dealt with the digital.  The pooling of expertise of the companies worked in spades.

Korg's modelling was at the front end of the technology at that time, nowadays that will have moved on a tad.  However, the range is much more than just a digital modelling preamp tagged onto a Vox AC amp.  As an electronics engineer myself I loved the fact that it's audio circuitry is genuinely unique in the sense that Vox's implementation of the common single 12AX7 valve modelling side didn't put it in the preamp where everyone knows it should be.  They built a full miniature mosfet power amp with the valve as the output pair feeding a small output transformer with its own internal dummy simulated speaker load.  This amp could be set up as Class A/B/AB by model selection and its feedback and voicing was altered to match the required gain and tone of the selection too.  This whole mini amp was used to drive an ultra clean high power current amplifier, again of unusual design, and feedback from that was applied back to the valve modelling amp via it's output transformer to its own feedback loop.  It worked remarkably!  Tone, response, feel, all were as good as a valve amp.  Right down to the need to get the master volume up past 1 o'clock to make it sing.  And power selection was possible without using a soak so you could select 1W 10W 30W 120W without any change to tone as the only thing affected was the ultra clean amp which was just boosting the finished signal.  The idea was not to sound identical to the range of amps it modeled, there is no point, the purists will never accept that.  It was to produce sounds close enough to them to be in the family but good enough in their own right to class as worth buying and to model the feel and response of a valve amp in a SS unit.

Any way, enough blethering.  Assuming there is something in my idea that the output transformer is part of the roughness which cannot be totally removed or compensated for within the electronics, I'm looking at the idea of setting up a dummy pseudo 2 way crossover to bleed off some of that top end to a non-existent high frequency unit.  Resistors don't give that roughness that piezo drivers do!  If there's anything in that setup then it may be a way for you to dial in your adjustment at will when it's needed.

Very Good Bordonbert, glad you read me in the spirit I intended     Just in case you are wondering about my V30 loaded cabs now I have the pear cabinet. I treated myself on my birthday to an Egnater Renegade 65w valve head which obviously doesn't have as many tricks up its sleeve but with the EL84 - 6L6 blend or select feature it is a tone sculpting wonder.

All the best

bordonbert wrote:EXCELLENT news HwyStar!!!  I've followed your reports of your finger problem and was hoping that you would be able to give some good news soon.  Hope you're back with the rest of us, sipping tea in a dignified manner with neatly extended pinkie very soon. Very Happy  I've got a suggestion that might help, a neatly fitting slide makes a wonderful splint  Smile and it may just give you the impetus to try a bit of practice of that aspect of your playing without allowing you to stress the damaged digit.  Or follow the Django Reinhardt school just for a while and just keep on telling the world to fork off with the first two fingers of your left hand.  Embarassed  Patience!  You'll get there mate.  Mind you they do say "Patience is a virtue, possess it if you can. Seldom found in woman and never in a man".  At least, my wife says it!

Thanks for the kind words Bert!  Much appreciated.  My wife and I have started using this "Green Juice" from Amazon: Link.  It has helped with our arthritis and inflammation issues.  I think it may be helping my finger issues.  

I am a little nervous to pick up the guitar again because I don't want to have that pain in my finger again.  I know that I should concentrate on using that finger less aggressively than I have in the past while playing. Thanks Man!

HwyStar wrote:
Thanks for the kind words Bert!  Much appreciated.  My wife and I have started using this "Green Juice" from Amazon: Link.  It has helped with our arthritis and inflammation issues.  I think it may be helping my finger issues.  

I am a little nervous to pick up the guitar again because I don't want to have that pain in my finger again.  I know that I should concentrate on using that finger less aggressively than I have in the past while playing. Thanks Man!

Not to hijack the thread at all, just a moment to pass along some info!

Look into a supplement called Cissus Quadrangularis. A lifetime of BMX, Skateboarding, Snowboarding, and powerlifting has left me with more than my share of bumps and bruises, not to mention the joint issues you`d expect. Top that off with a 12 hours a day practice regimen while at GIT back in the day taxed my hands well into chronic Carpal Tunnel syndrom (which I had treated with acupuncture 15 years ago and had zero pain from it since). The Cissus has no side effects and is not expensive, and I will personally put my own name on it as an effective, nearly miraculous supplement for joint issues. I recommend finding it in bulk. Take twice the recommended dose for the first two weeks, which will eliminate your pain and kick start the healing, then go to the regular dose recommendation for maintenance and repair. It really does work, like no sh*t.

Well I for one appreciate the info from other players about treating hand problems. When I got trigger finger in my left (fretting) ring finger two years ago,I couldn't find a player who had the surgery or had successfully dealt with that problem. Fortunately, mine didn't get worse and was manageable - then I lucked out and my primary care doc hit it just right with a steroid shot and released it. But I'm always dealing with tendonitis, and this summer strained the A2 pulley in my left ring finger - that f'in hurt and caused me to miss a gig. I'm still wearing a splint on the finger. Anyway I'll research t these two products and maybe check them out. The green one is gluten free, so that helps me. I can only take so much ibuprofen...

From direct experience, all hard tissue joint problems can usually be helped with Green Lipped Mussel extract.  There are lots of it about but from my own experience the best of the bunch seems to be Seatone, (I have no connection).  As a liffetime, (a long one), martial artist to a professional level, it has kept me going through some extremely awkward and silly times!

Green Lipped Mussel effectiveness

DON'T buy that supplement in the article, it isn't needed at all.  It isn't just for arthritis though it is very good for that condition. Seatone is available almost everywhere now and is very effective.  Not suitable for those who have shellfish allergies!  It's no good for soft tissue injuries but for bone and joint capsule cases it's brilliant, and quick acting too.  I've recommended this hundreds of times to people over 40 years and I've only had 1 person say it didn't help.