# Unconventional low voltage tube amplifier



## pilovis

This is my personal project: *Low Cost 2+2 W tube stereo Amplifier @ 60Vcc*
   
  This amplifier uses two tubes per channel: PL504 (EL504) and ECC82.

 The performances are very good in spite of such a low unconventional supply voltage.
   
  The output Audio Transformer is 800/8 ohm impedance, but if you accept a little bit lower bandwidth (low frequency cut < 100 Hz ), you can use line transformer 220/24 Vac (not less than 35W to avoid dc saturation).
   
  Note: in all my prototypes I used line transformers as output transformers.
   

   
  The above schematics is for one channel, uses two triodes preamp (common cathode and cathode follower).
  The supply voltage of 60Vcc is achieved using a diode voltage doubler and a 15+15Vac Line transformer.
   
  Version 2:
   

  (stereo) version with just one triode preamp per channel and without the diode voltage doubler (transformer @ 48Vac).
  In this version I used EL504 (6.3 V filament) instead of PL504 (27 V filament).
  - Protototype 1:
   

   
  - Prototype 2: MP3 Tube Stereo Amplifier
   

   

 -Prototype 3: Stereo Amp with line transformers used as output transformers
   

   
  - Test: Stereo Amp with line transformers used as output transformers


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## nikongod

Neat project! 
   
  Have you considered a push-pull output stage to reduce the offset current & saturation in the transformers? Parafeed is pretty fun too 
   
  Also, if you have not tried them out Edcor makes some very affordable GAPPED transformers for SET tube amps. Totally worth a look if you want to stay with series-feed SE.


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## trimer1

The magic eye looks amazing o.o I may consider it for my next project


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## havazli

Hi,great and cheap amplifer.I guess you're quite experinced.So let me ask you a question:
 What if I heat in such way a PCL86 (13.3v) and ecc83 (6,3)?
 Roughly I mean this:
*____________           -------I*
*I                                                 I*
*I                                                 I*
*I                          PCL86 -13,3v*
*I____________                      I*
*I                           I                     I*
*I       ECC83 - 6,3v                   I*
*I____________I       --------I   *
  
 May I?  Thanks in advance?


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