• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

24v tube buffer & line stage schematic

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#7
Bem-bem said:
for shoog, can you give me "audiodigit" tubalizer & tubepre complete schematic ? thanks
Click to expand...

A simple search of the forum would have found it. :smash:
I made my own schematic of the Tubalizer ( Unfortunately, I bought one for 80 Euros!!!). I had problems when using it on the recommended 12V but it works very well on 24V. It is supplied with a 6SL7 but I prefer to use it with 6SN7. I recommend designing the 6volt heater regs on a seperate supply if possible because the regulator gets REALLY hot when fed with 24V, especially with the 6SN7.

You should also read this thread. AlaistairE has designed a very nice low voltage pre that would be great for 24v. I have tried it and it's very good. http://www.diyaudio.com/forums/showthread.php?s=&threadid=89195&highlight=

Kind regards,
Martin.
 

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#9
jleaman said:
Sonusthree,

what kind of charictoristics changed when you up'd the voltage from 12v > 24 ?

Wouldent it be easyer if yuo just used a nice 6V battery insted of a regulator ?

Jase
Click to expand...

Hi Jase,

I found that it distorted badly at 12v but your experience may be different. It is commercially available design (80 Euros) and was made to run from a 12V wall wart. No problems at 24V for me. Actually, It would probably work OK at 16 - 18Volts but I haven't tested this myself.

A 6volt battery might work but I wouldnt like to replace the battery and, at this low voltage, I would imagine that the correct heater voltage would become more important. I'd rather stick with a 9 or 12volt supply to a 6V regulator for now.

I have commented further in this thread (that you have also posted in): http://www.diyaudio.com/forums/showthread.php?s=&postid=1199466#post1199466

Cheers,
Martin S3
 
#10
#13
Simpleton said:
Simple grounded cathode line amplifier stage using ECC86:

R(grid bias): 100k
Rk: 160Ohm (or closer)
Cathode bypass cap: 50uF
Ra:2.5k
B+: 25V

Vin: 1Vpp
Vout: 10.25Vrms
Ia: 3.1mA
Ia max: 3.5mA
Calculated distortion (2nd hamonic): 1%
Click to expand...

Ra*Ia = 7.75V
Shouldn't possible to get 10.25V rms out (that means 14.45V peak) beacuse on the anodic resistor there is no enough volatge headroom.
The distortion of 1% seems too optimistic, in practice I think will be 1% at few volts rms.
 
#19
plovati said:
This one works from a 12V battery:

http://www.audiofaidate.it/forum/uploaded/plovati/PREcario_darlitotem_lowres.JPG

gain 13.7
BW (-1dB) 12Hz .. 250kHz
clipping Vout max 3Vrms on 27Kohm load
THD at 2Vrms 1%, 2nd harmonic only
THD at 1Vrms 0,78%, 2nd harmonic only ( -50dB)
output resistance less than 600ohm
Click to expand...

We re-organized all the AUDIOFAIDATE forum, noe we're on www.audiofaidate.org Il sito indipendente degli audiocostruttori.
Please take note of the new link to PREcario low voltage tube preamplifier
New link:

http://www.audiofaidate.org/uploaded/plovati/PREcario_darlitotem_lowres.JPG
 
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