Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[J M Fahey]

Weell, I see that Jordan has been pulled out of the picture. Interesting.
Let's continue with the remaining contestant: Triumph
1) I see Jimi courteously explaining some licks to a friend or whatever, on a guitar that looks like an italian made Vox (maybe now we should consider it his main axe too?) ... which might be his or the other guy's, for all I know.
Any pictures of Jimi *actually* playing Live or in Studio with a Triumph?
2) SS Triumph amps the *main* amps in Keith Richard's rig?
Not so sure.
I'm talking about Keith Richards the Guitar player, of course.
Now if we talk about Keith Richards the BASS player, well, anything is possible.

Anyway, I'd *love* to see (40 years later ) the Triumph schematic.
Thanks in advance.

[Eric D. Larson]

I have a question you guys probably would be able to answer. I have a 1978 Peavey Pacer 1-12 combo that I am trying to get into playing shape (just for kicks). On it's own, it doesn't sound too bad but, I plan on using pedals. (Wampler Plextortion & Wampler Tweed '57) for dirt. It has built in reverb that isn't so good & I thought about having an Accutronics long spring type of reverb put in it. I had the pots cleaned recently & thought I would also upgrade the speaker too. The back panel says 45 watts RMS- 8 ohm & I ordered a Celestion Patriot Black Powder 8 ohm- 75 watt. I haven't installed it yet but, wonder if this speaker is adequate to use. Also, is it safe to use pedals slightly louder than unity gain ? Thanks for sharing what you may know. Eric

[phatt]

Weell, I see that Jordan has been pulled out of the picture. Interesting.
Let's continue with the remaining contestant: Triumph
1) I see Jimi courteously explaining some licks to a friend or whatever, on a guitar that looks like an italian made Vox (maybe now we should consider it his main axe too?) ... which might be his or the other guy's, for all I know.
Any pictures of Jimi *actually* playing Live or in Studio with a Triumph?
2) SS Triumph amps the *main* amps in Keith Richard's rig?
Not so sure.
I'm talking about Keith Richards the Guitar player, of course.
Now if we talk about Keith Richards the BASS player, well, anything is possible.

Anyway, I'd *love* to see (40 years later ) the Triumph schematic.
Thanks in advance.

Hum Triumph, Was it not connected with Selmer or Vox in some way?

I remember reading that some SS Vox Amps where made in the triumph factory.
Anyway I just found this; http://vintageamps.com/plexiboard/viewtopic.php?f=10&t=78014
Pics are gone and I don't know if it refers to SS.

Ed; maybe it is SS read this first; http://vintageamps.com/plexiboard/viewtopic.php?f=4&p=373589
Phil.

[phatt]

I have a question you guys probably would be able to answer. I have a 1978 Peavey Pacer 1-12 combo that I am trying to get into playing shape (just for kicks). On it's own, it doesn't sound too bad but, I plan on using pedals. (Wampler Plextortion & Wampler Tweed '57) for dirt. It has built in reverb that isn't so good & I thought about having an Accutronics long spring type of reverb put in it. I had the pots cleaned recently & thought I would also upgrade the speaker too. The back panel says 45 watts RMS- 8 ohm & I ordered a Celestion Patriot Black Powder 8 ohm- 75 watt. I haven't installed it yet but, wonder if this speaker is adequate to use. Also, is it safe to use pedals slightly louder than unity gain ? Thanks for sharing what you may know. Eric

Hi Eric,
        A big fat huggy welcome.
The speaker will be fine though it may alter the sound/tone a bit.
Reverb,, don't waste money on a fancy tank as the likely culprit will be the electronics that drive it all. You seem to like pedals so just go find a good digi rev pedal and save the pain of completly redesigning the rev section.

Pedals,, Assuming the Amp is in good working order then highly unlikely that any damage will happen to any amplifier by winding all the pedal knobs to 10.

Go for it.
Phil.

[Eric D. Larson]

Phil, Thank you for the nice welcome & advice. As you may or may not know, there is a control on the front of the Pevey Pacer amp that says overdrive. It is subtle but, it works. I'm wondering if there is a way to change the curcuit to make this control become more effective & intense ? I also have an old Peavey Decade which to me sounds amazing - (much smaller amp but far more dirt capability) it has 2 inputs, one clean & one called saturation. Is there any way to use the pre and post gain controls (curcuit) from the smaller amp & put them into the larger Pacer to essentially make a larger version of the Decade married to the power section of the Pacer ? This would seemingly eliminate the need for a dirt pedal altogether. Just wondering. Thanks, Eric 

[mexicanyella]

Eric, I've played through a Pacer before (my buddy across the hall in the college dorms had one) and to my ear, that brand of mild, kind of greasy-skanky "Lynyrd Skynyrd-esque" distortion is great for all kinds of rock and blues, but to appreciate it you sometimes have to hear it in context. In other words, it might sound pretty lame to you if you just got done rocking out through a Boss Metal Zone pedal or using a Marshall JCM900 in a room by yourself...but when you hear that Peavey grit in a mix, it can really cut through, carve out a spot for itself to be heard without stepping all over the bass, vocals or other guitars.

Having said that, I've had great results with my slightly newer Peavey Audition 20 (early 1980s), which probably falls somewhere between your Pacer and Decade in terms of available dirt level, by setting it pretty loud and with a medium gain setting, so playing soft sounds pretty clean and playing hard gets noticeably dirtier. Push the output volume and speaker hard. And if you have it set like this and in front of it you place a clean boost pedal (I use an old beat-up DOD FX-10 Bi-Fet Preamp, but there are many others...some distortion pedals can also function as a clean-ish boost) you can get some great tones by having the amp on the verge of crunch, then pushing it into freakout zone by hitting it with a hotter signal.

I also like using a compressor pedal in front of the amp, set at a pretty mild, conservative level. I don't want to hear a special-effects squashed sort of compressed signal; I just want to hear a slight limiting on the peaks, and a slow enough attack that my pick attack comes through a bit...this seems to approximate the slight sag and compression that a tube circuit might display at the onset of overdrive.

Anyway, try those things before chopping into either of your amps...you might find a combination you like.

[teemuk]

I remember reading that some SS Vox Amps where made in the triumph factory.

Yep, they were a subcontractor to the company that owned the Vox trademarks. They designed a few models and manufactured some other. If I remeber right they designed the 7 and 4 -series hybrid amps and the PC board AC30's.

Anyway I just found this; http://vintageamps.com/plexiboard/viewtopic.php?f=10&t=78014
Pics are gone and I don't know if it refers to SS.

I was going to post that when JM Fahey asked for the schematics. I have those schematics saved somewhere but I have an ungodly pile of CR-ROMs full of schematics in no sorted order and it takes a good hour to start browsing through the "suspects".
And for what...? A schematic of a generic solid-state power amp with generic current feedback scheme. All you knowing what the talk is about know what to expect. There's really nothing to see; the only remarkable feat is how early they did it.

[joecool85]

With those parameters in mind , it was easy to calculate values which I use even today .... and by the way my 1972 network is much more efficient and simpler than that used by , say, Polytone, Crate, or most others, even today.

Juan, I still don't count you on this until you start selling these in the USA.  Bring on the quality Solidstate, discrete electronics based amps!

[Eric D. Larson]

Thanks for the advice mexicanyella !  Gonna do that !

[mexicanyella]

Also, speaking of Peavey Pacers, check out what this guy on the steel guitar forum did; built a finger-jointed pine cabinet for a Pacer chassis and two 8" neodymium-magnet speakers.

[J M Fahey]

COOL !!!!
I LOVE when these trusty workhorses are kept living (and improveed), instead of sending them to the dump.

[sessionman]

I noticed that effect on my own a ***long*** time ago.
I started making guitar amps in 1969 , all tube of course.
In 1972 Argentina defaulted on its external Debt (what Greece is about to do now) and, not having U$$ available, imports were impossible.
Tubes dissappeared from the shops, just like that .... or were worth their weight in gold.
Started using Transistors, which were still affordable, but noticed that the sound was not the same.
Part of it was that SS amps had too high damping (approx. 100 ) which caused "dry" bass; I measured my Twin Reverb type tube amps, and damping was around 1.
I added current feedback (straight from SS design books) until I got the same value.
It helped a lot.
I guess I invented "Valvestate" on my own, about 15 years earlier than Marshall, go figure.
Necessity is the Mother of Invention.

Hello Gents,

Just joined to make a few comments.  You might guess who I am from my username.  :-)

It was almost impossible for Jim Marshall to have known about CF, as he didn't even understand valves.  Until he started to employ decent designers post 1988... nothing very revolutionary came from this stable.  So it was his new design team that introduced CF to the Marshall brand!

CF circuits were used as the basis for 'reverb'  drive circuits designed by Accutronics back in the early days of tranny amps.

[sessionman]

I think it really falls down to how each individual perceives certain characteristics in tone.

Personally, I hear the effect only as slight boost at low and high frequencies. I usually have to struggle to hear it as well.

Then again, I've encountered people who say it makes an astounding difference. Last one saying so wasn't even talking about current feedback per se but about differences of running a 100% tube amp to either purely resistive dummy load, or to a dummy load that mimicked speaker impedance. The effect / difference is essentially the same.

For him the resistive dummy load was too sterile, the reactive was "squishy" and responding to playing dynamics making a "Night/Day" difference. Personally, I had to struggle to hear the slight difference. ...as usual.

I once angried someone by stating that only thing the "Reactance" control in his Rocktron Velocity did was basically equivalent to diming bass and treble controls of a generic HiFi -style EQ - nothing else. He got mad insisting the control turned his amp to touch-responsive dynamic setup that sagged like a real tube amp.  ...all that from a generic boost of low and high frequencies. The control didn't even try to mimic the unique response of a poorly damped amp driving a loudspeaker. It just introduced a basic treble and bass boost.

It's all in how you perceive things, and perceiving can be based 99% on imagination and 1% on "real" auditory information. It's always more or less subjective. Therefore I wouldn't jump to definite conclusions too quickly. Yes, objectively viewed the damping barely has a slight effect on frequency response... but so far I never encountered anyone who would sense things 100% "objectively".

CF is more about the control of the speaker than more treble or bass... although that is also perceived.  It's allowing the speaker to add 'mechanically generated' harmonics.  At frequencies above 1000hz approx, the HF response of a typical guitar speaker is largely synthesised... not natural HF sound coming from the amp.  This is produced by 'cone break-up modes,'  which are characterised by the somewhat jagged speaker response curves above 1000Hz seen in speaker manufacturers publications.

Most players think of a speaker as reproducing the sound made by any amplifier.  Which is incorrect to a high degree for tube amplifiers and modern SS amps with CF.  In fact, the amplifier does produce a controlling signal, but the guitar speaker simply uses it as a motive force and, basically, interprets that signal as a 'new sound' containing those harmonics which did not come from the amplifier at all!

The art of good guitar tone is understanding these 'beneficial defects' in the components you use.  When you understand what is going on in the complete article, then it is possible to exagerate them or subdue them, to whatever your sonic aims are.  This is exactly why there are so many speaker models available on the market.

A great guitar sound wil be determined mainly by the speaker and how it interacts with the OPTX and cabinet loading.  So CF is only the 'enabler', whereas the speaker really creates the sounds you actually hear... not so much the trannies or valves, or any other component to any significant degree for that matter.  Without CF in a tranny amp, the speaker is effectively just a resistor that makes a noise in line with what it's fed; who's loudness is proportional to its changing impedance with frequency, unlike a compensating transformer output stage.

The designer plays a big part in this to.  If a designer is into metal... then he will not be able to design a good country, blues or any other type of amplifier.  As with any 'niche' market product, the designer wares the true assets in the form of his knowledge on how to bring all the convoluted defects together and achieve a desired outcome.

It ain't just about the technology or circuitry used!  The understanding of how the sound is made is more important than being a superb electronics technician!  It's a black art... and so is designing guitar speakers!

[QReuCk]

Thanks for this explanation. Not so sure I understood all of this, but it's an interesting point of view.
I'm just wondering if these non linearities that are enabled either by a tube/output transformer or by a SS amp with CF are in certain cases what causes the dynamics of the playing to be exagerated.
Wouldn't say for sure I have a comprehensive understanding of what "linear response" to dynamic playing should hear like, but I'm usually pretty good at producing the sound (both tone and volume) I want with accoustic guitars and at controling the distortion level of a crunching preamp with just how hard I attack the strings. Fact is, on some tube combos pushed in there usually prefered volume range, I often struggle to control these dynamics, generating barely audible sound when plaing soft and ice-pick-through-the-ears far too loud notes when picking just a bit harder. Just in the interest of better understanding, could you tell me if the dampening factor might play a part in this?

[sessionman]

Thanks for this explanation. Not so sure I understood all of this, but it's an interesting point of view.
I'm just wondering if these non linearities that are enabled either by a tube/output transformer or by a SS amp with CF are in certain cases what causes the dynamics of the playing to be exagerated.
Wouldn't say for sure I have a comprehensive understanding of what "linear response" to dynamic playing should hear like, but I'm usually pretty good at producing the sound (both tone and volume) I want with accoustic guitars and at controling the distortion level of a crunching preamp with just how hard I attack the strings. Fact is, on some tube combos pushed in there usually prefered volume range, I often struggle to control these dynamics, generating barely audible sound when plaing soft and ice-pick-through-the-ears far too loud notes when picking just a bit harder. Just in the interest of better understanding, could you tell me if the dampening factor might play a part in this?

CF will not present you with a solution to your endeavours sadly.  It is so easy to get wrapped up in technical 'stuff' that might bring hopes of an instant 'playing' problem cure.  Guitar sounds, in any genre, are helped mostly by the ability of the player and many years of experience of playing.  Particularly in a live situation where 'feeling' the sound is so important and balancing pick pressure against drive and volume is a real skill to be learned. 

Trying to abtain the characteristics you seek in a domestic environment might not bring much fruit.  Attempting to recreate recorded sounds are too, a waste of time.  They are mic'd with microphone(s) (there may be two or three used in various placements to create a sound) that add their own harmonics to the tone, then EQ'd by an EQ that works at different frequencies to guitar amp EQs, compressed... need I go on?  A complete non starter!  Not even the original artist can copy his recorded sounds exactly!

I know some very clever electronics designers who cannot design a decent guitar amp.  Designers should have 'experienced guitarist' on their CVs to qualify.  Many of the 'nonlinearity' and other attributes that pure technicians bestow upon guitar amps, although measurable, provide very little audible difference to a guitar amp tone.  By the same token, I know many excellent players who just cannot find a great sound, even with boutique equipment.  They either have it or they don't, or they need to practise more playing live.  I guess... to be brutally honest.  Most really experienced players can get a reasonable sound out of almost any old amp... on demand.  CF is not the panacea.  But it does help a tranny amp to sound much closer to an amp with an output transformer.

Ice-picky tone at volume is normal.  The human hearing responds better to high and low frequencies at higher volumes (see Fletcher & Munson's work).  You should EQ the amp for the volume you're playing at!  Amps with a cheap output transformer, like guitar amps, also have narrowing bandwidth ability as they become heavily driven/magnetised.  Hence Peavey's 'T-Dynamics' circuitry.  But you can simply EQ the amps for loud playing... always refer to what your ears are telling you!

Hope this is helpful.