John Truba's Blog

Catch up with my musings on music and everything else in the world of Valve Amplifiers

The Beginnings

Yes folks    it's 40 years in existence  ,  albeit on a lesser scale than most  companies  ,  though having  been making  Audio / Musical  Equipment  of  one  sort or another  since about 1964  ,  the  first  "Jaytronics"  badged equipment  was made in 1981 , many pieces of gear previously  but no name applied  , when  I  think back to what  was made then  ,  it beggars  belief  ! 

 You see , in the 60's , we were all fed on a diet of  " Camms Comics "  as we refered to them  ,  namely  " Practical Wirteless "  ,  " Practical  Television "  ,  " Wireless Wor;ld "  and other monthly  publications  .  As well as repairing   Radios ,  TV's , Record Players and such like  , one  would ( on a Saturday ) visit all the Electronics surplus  stores scattered  about Greater London  ( though mainly  Central London )  and  buy up  ex Forces ( Army , Naval and  Airforce )  equipment and other electronic bits and bobs .  So gleaning info' from " Camms Comics "  and few ( rare ) books available at that time , inspired one to experiment and build away .  Mainly amps and very simple effects  for  guitarists   ,  this approach carried on for  a good few years  and then later it dawned on me  - I need a name , logo , badge    call it what you will !  .

" Jaytronics "  seemed so logical  , so from 1981  everything made was badged  " Jaytronics "  .  I shudder to think of the variety of equipment made  , anything and everything to do with Audio / Musical applications  , though never Video or Digital  , even though having worked in companies that boasted  Digital  Electronics since late  1968  up  to  1985  , it never entered my head to go that way , having been brought up in the Analogue World .

So fast forward to the present day  though with some degree of hesitance noting the strange / wierd   , days  , weeks  , months  we're all going  thru' ,   to play Gigs and Jam  with other musicians  just can't come quick enough , to put it simply ! .

Back to " Jaytronics "  during this  " Down-Time "  I've been busy with some  manufacturing of equipment for customers , some stock replacements  and of course  the  repairs  , modifications ,  servicing equipment  and  even  splitting down  a large  bass  combo  ( made  a good while back )  to  an amp head  and speaker  cab for  different purposes  .

Currently in stock  I have  combo's and amp heads from  15 watts up to 200 watts  , there is also a lovely sounding Valve Reverb unit  plus  a couple of  2 Ch. Valve  Recording Pre's   if  anyone is interested  !!!      As always  I welcome any  inquiries as to custom building for clients .

Stay safe  and  as the government  advises  ,  don't  wander off more than 500Km's   -  otherwise you'll be swimming  !!! 

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New Ideas , concepts .

I have'nt had much to say about valve amps for the last many months , but the braincell is at work all the time trying to come up with something novel  , Pause , back in 94/95  I came up with a design for a 50 watt head with 6 EL84's in Push-Pull  at the behest of a guitarist friend in Co Cork  ( now emigrated from our shores ) . I believe it was a first , a Hex84 cct.  . The EL84 valve is my favourite valve , if you use one in single ended Class A  say 4 to 5 watts  , you've got an ideal practise/ recording amp  , without being too loud .  2 EL84's in Push-Pull can give you 10 to 15watts of lovely guitar tone depending on type of cct employed .and of course 4  EL84's are the classic power stage of many an amp. notably the AC30  arguably the best guitar amp ever !  I took it a stage further in 94/95 with  6  EL84's  , it put out a clean 50 watts thru' a self designed output transformer that took a day to wind all the bifilar windings , I say it myself that was a good amp , wonder if it's still somewhere in Co Cork ? . Which brings me back to the current time . The autumn months were'nt wasted  ,  I was working on a new development  which appears to be fruitful  , A Dual output mode amp which uses a common pre-amp. voicing  But is selected to 2 different output stages  using a common output transformer  with only minor trade off's  as regards optimum matching .

So far I've built  a 100/30w valve head EL34's (4) and EL84's (4)  to give the respective 100watts and  30watts  , also a lesser powered 15" combo amp  using  2 5881's (30watts) and 2 EL84's (15watts) and they both sound great  . They are complicated beasts  and it cannot be used in channel switching modes , But actually deciding which power or tone you want to play with , ie , the larger power suiting a larger venue , the smaller power for a smaller place , this is assuming sensible pairing with appropriate spkr cabs , ideally a 4x12" for larger venues (100w)  and 2x12" for lesser places (30w) .  I dread the the thought of single 12" large power  cabs being used , as some major manufacturers do  " Infinate Sustain Boxes "  I call them , eg  ,  turn the contols up and hold the note  and three days later the same guitar note is still feeding back  . Powers in the region of a 100 watts need to breathe thru' multiple 12" spkrs  such as 4x12" cabs , long live " Marshalls"   . I personally cannot see the logic in making these very small 300watt speaker loaded  100watt valve amps  (which also belie their weight)  .

 This is all assuming you are lucky enough to be playing large venues where you can turn it up !        That's ROCK N ROLL  !!!   .

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A red Tape matter or should that be 3 and 7 .

Since learning the resistor / capacitor colour coding  system in early 1960's  I've used it to great advantage in my domestic life as well as ( obviously ) in Electronic aspects , you know the one I mean , ie , Black - 0 , Brown - 1 , Red - 2   and so on .  In the Electronics Industry when " wiring in " or " Looming up "  cables or wires  , one uses the colour coded system  type identifying Sleeves or Markers  , but when you're dealing  cables or wires that are pre-wired / fixed or have connectors already attached , then the use of coloured insulating tape can come into play . But this is where we hit a stumbling block . I've yet to find Orange ( 3 )  and Mauve / Purple (7 )  insulating tape available commercially  , ironically  the colours have been available in Mic cables and such like , but Not in " Insulting " tape ( insulating tape for the non-cynics out there ) . In my own workings what I do is , for 3  ( orange )  I use 1/2 width tapes of red ( 2 )  and  yellow ( 4 )  therefore the happy medium being 3   , and  blue ( 6 )  and grey ( 8 )  giving  a happy medium of  7  . I find this works perfectly because for the normal colours used  one uses the full width of tape  and the " made up colours " in 1/2 width .  

 So Please  " SELLOTAPE"  , " 3M"  and other tape manufacturers out there , give us this day our daily Orange and Mauve / Purple  insulating tapes  , and in anticipation of Mr Clever Dick out there  I've not been able to find them yet even if you have   . !!!  

  The system of colour coding can sometimes outwit ordinary numbers , when say used in potentially "dirty" situations , such  as in a multi-cylinder engine for spark plug recognition , where if a  numeric system was used  grime/grease  could make a dirty 8 look like a 3   or  a dirty 4 look like an upside down 7  and so on . With the colours used for a V8 engine  it  would be Brown -1 , Red - 2 , "Orange" -3 , Yellow - 4 , Green - 5 , Blue - 6 , "Mauve" - 7 and  Grey - 8 , and Bobs your uncle and  no misfiring of engine , I've used this appraoch myself and it's ok  . For Microphones  in a Recording studio  such as that  AKG C414  that would be Yel / Brwn / Yel  , that Shure SM 58  would be Green / Grey  and so on .  All the dark cabled  leads to and from Mixers / Recorders / Outboard Equipment  where only a silver or white marker would do ( you try and find a good one that doe'snt immediately shed its colour when disturbed )  can benefit from the tape system , Of course if you have white cables then you can use coloured Magic markers to do the job , but bear in mind that over time the ink does fade .

 Back in the day when I was working in my first job ( an apprenticeship ) with a company called  "Lustraphone "   ( we pioneered Europes first Radio-Mic systems )  amongst all manner of jobs I was working on  , I sometimes had to work on M.O.D. stuff  , this was all right angles in wiring , neatness personified , daily checks by the man in a black suit , white shirt and dark tie  there was a protocol of colour coding for Valve stuff where only Red was used for high-tension , Black was Chassis/Negative , Green was Valve i/p grids , Blue was Valve Cathodes  , Twisted Green for Valve heaters  and a few other codings which I 've forgotten  . But alas todays modern approach seems to have ignored all the sensibilities of yesteryear  , so in some circumstances any colour could be high-tension , point here is never assume , you know , it makes an ass out of  Blah Blah Blah ,      See you soon .        

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Sad loss in the Drumming world .

It's a while since I last blogged , but have been prompted by the sad news this last weekend of the passing of my favourite drummer , namely the late great Ginger Baker  . Not really knowing the finer points of drumming  ( as is evidenced on my own "Showcase"  double C.D. " ' Bout time 2"  made more than 5 years ago )  it would appear on some tracks that the drummer would have needed more than one pair of hands and feet , anyway that's another story .

But  I  always liked what Ginger put down on record and "Live"   , especially the fabulous "Cream" stuff  and a bit later the wonderful  " Blind Faith "  with only one  Album  and  limited performances  ( i was lucky to have been at the famous live one in London's Hyde Park back in 1969 )  .  I particularly liked that Ginger was using the "Toms" more than say  Cymbals  and to me as a guitarist it made sense as regards time keeping in songs/ instrumentals  , it was easier than listening out for 16ths or 32nds on the Cymbals  , the "Tom-Tom"  rolls were easy to follow in between verse , choruses  etc  etc  giving the other members of the band perfect cues .

 Yes   Thankyou  Ginger for your valuable contribution to the  BEST  period in music making  , the  late 60's and the 70's  , when bands played  REAL music  unlike the crap we have to suffer these days .

 R.I.P.  Ginger    and  before  this  also  Philo' , Rory  and  Gary  , wonderful musicians them all .    

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50 year + guitar solo enigma unlocked .

If you were a teenager in the 60's as I was ,  doubtless you probably watched the "Monkies"  TV shows  which were the rage for a while , featuring songs , antics  et all . One song which heralded quality was " Last train to Clarkesville"  which had (has) a beautiful lead solo  which proved to be an enigma to the majority of us guitarists ( Yeah there's gonna be the clever dicks out there who sussed it out in 5 minutes )  but I personally did'nt know anyone who had it off pat .  We thought along the lines 2 or more guitarists doing a ascending G modal movement  , but try as I did  , could'nt figure it out , till last week  , through having to work it out for a new band project I'm doing and the other guitarist checking out You Tube  ( I've never done this before  always worked things out from just listening , god knows what rock I've been hiding under )  and telling me yes the guy that did the original solo has  done a video on it  . Wonderful !!!  I checked it out  and yes it was a chap called Louie Shelton  , it was his entrance to the world of session-work apparantly .  Within minutes of seeing this video  it all became patently clear  and the solo has been nailed  . Previously in a London based pub-rock band in 1977 we tried to do this very number  but were totally confused  ( 3 guitarists in the band )  ironically that is the amount of guitarists it took to do this wonderful sounding solo . One playing alternating  Gmaj7 to Fmaj7 chords and back again , the second guitarist playing a very simple motif  at the 10th  fret at the  top  E and B strings  and the main man himself  ( Louie)  playing arppegiated  inversions of  G and F ascending and descending  and finally ascending again  to what was considered by everyone I knew  to be a cracking good solo . We had thought this was done by a pedal steel player in conjuction with a standard guitarist because it is a very confusing solo to listen to , all sorts of guitar sounds emanating   so one would'nt be absolutely clear about what's actually going on  .  It's an absolute breath of fresh air to finally know how it was done , just imagine that they went into the studio probably not knowing what's expected of them  and coming up with this class of a solo , give me this sort of playing any day  to the boring crap done by todays modern "Tappers"  not forgetting the "Wammy bar"  merchants all trying to do a million notes a second   bumble bees and wasps stuck in a jar  come to mind .  Now where's that 14 gauge top string I was about to fit to my 335 .

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