# OTL CLASS A TUBE AMPLIFIERS



## claudiomas

6SL7 / 6V6 GT class A     OTL headphone amp    SOGNO


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## Happy Camper

So stranger, what ya driving with it?


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## alvin sawdust

Welcome to head-fi.
   
  Strange first post old friend. Any more clues as to the point of the thread?


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## claudiomas

Hi,
  this diy headphone amp its a modified version af a classic ciuffoli otl headphone amp.
  same conception, but both triodes of 6Sl7 are paralleleds ,
  the 6V6 are in pseudotriode mode , cathode resistors , non inductive 25 watts ,
  mounted on front panel aluminium 5mm , (wen the amp its ready front panel its warm).
  HT come slowly in 3'.
  i'm sennheiser france technician,
  so i tray many higt grade headphones.
  the HD 800 demand to take a sit, just wonderfull, time stop and you are in the middle of the orchestra.
  my headphones : HD 25 III 600 ohms, HD 515 50 ohms , SONY CD 3000 32 ohms.
  everyone tray it , was stupefied
  sorry for my bad english, i'm italian.


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## alvin sawdust

Was it expensive to build?


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## claudiomas

not so expensive.
  chassis its abs 1U rack
  alu front and 2mm aluminium top
  tubes russian reflector nos military   
  power transformer made in italy by novarria
  octal sockets, very good capacitors ands PR2 resistors
  catode non inductive resistors,
  btr screws, neutrick jack outputs, gold chink inputs.
  it cost me 250 euros
  but the result its magnificent.
  and i can sell it easyli at 500 euros.
  it can drive grado 32 ohm and sennheiser 300 or 600 ohm
  easy
  but need  labour and experience.
  sorry for my bad english
  claudiomas


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## Uncle Erik

Would you be kind enough to share a schematic?


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## MrGreen

x2 on the schematic. I've suggested this thread be moved to the DIY forums since I would assume the average viewer there is more into this stuff.


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## n3rdling

Cool looking amp


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## Planar_head

Sennheiser HD800's and an OTL (what appears to be SET) sounds like a very interesting match.
   
  Looking forward to looking at the schematics.


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## MrGreen

For those who are unfamiliar with the Ciuffoli 6C33C OTL. It appears that the OP has modified the schematic, however.


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## alvin sawdust

Claudiomas your english is fine.Are you likely to build any more of these?


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## claudiomas

the original ciuffoli schematics:

   
   
  this its not my first headphone amp, not my last.
  thanks for the interest
  claudiomas


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## claudiomas




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## claudiomas

Quote: 





mrgreen said:


> For those who are unfamiliar with the Ciuffoli 6C33C OTL. It appears that the OP has modified the schematic, however.


 
  Mr Green
  i come from old scool,
  less components,
  best soud, easy tuning.
  the ciuffoli 6C33 OTL
  should be a 1class amplifiers,
  but let Mr Ciuffoli OTL class A basic design
  be the best for DIY,
  ground hum its easy to solve
  very fews resistors and condenser,
  the tubes  class A SE OTL
  y love it.
  and i'm not alone.


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## claudiomas

the soft start HT power supply:
(zener 265 Volts)


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## claudiomas

this headphone amp its hot, clear
  i'm satisfaied.


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## pabbi1

Started toward the 6v6 (bless you Leo Fender), but then wandered to the 6005w, and finally to a kissing cousin (NDA protected). Any reason to use 6v6 over 6005w?


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## claudiomas

military reflector russian 6P6S


   
   
  of course the best its on my fender champ


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## claudiomas

the 1rst point its sockets
  i'm tired of noval ,
  octal sockets and bigger tubes
  ares most reliables.
  an more beautyfull.
  and y love olds fabbrications .
  claudiomas


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