Vacuum tube amplifiers

[efren]

Nobody seems to start here a topic or at least kinda interested regarding this primitive technology, IMHO they are the sweetest, warmest, full of emotion sounding amp on planet Earth, that no expensive solid state  or gain clone can equal when it comes to sonic qualities that a vacuum tube amp can offer, I know these are totally alien in younger generation   but for "seniors" like us in the DIY electronics (particular in the audio aspect) field, these metal contraption enclosed by a fragile glass in a vacuum state, are indispensable when it comes to serious & intimate listening.
The cathode ray tube commonly used in older TV's & monitors are legit Vacuum Tubes, gradually replaced by LCD's & LED panels, but vacuum tubes used for audio are slowly coming back, one proof is China(sorry but no mention of brand)  produced a cheap hybrid version marketed locally, not to mention hi-end manufacturer abroad, some particular tubes have cult followings here & abroad.
A member here with a handle of Tony is one influential figure that influenced me to tread the vacuum tube path, & the saying among tube
enthusiast "once you tried there is no turning back" is true in my personal perception & expirience.

Just my fifty cents  

[tony]

Hi Efren,

welcome to the forums, please post your tube projects for other members to see and enjoy.....

[insomartin]

welcome sir efren!

[efren]

Hi Efren,

welcome to the forums, please post your tube projects for other members to see and enjoy.....

@sir Boss Don Martin,

Thank you sir!


forgive my stupidity sir, di lang ako nagbrowse, marami pala dito BTW excited na ako dun sa 6p15p, the suppressor grid is isolated pala unlike the EL84 internally connected sa cathode. Further research ask for a 9.5K plate load @ 330 VDC max.
kaya pwedeng manipulate as mentioned in the DECWARE site pwedeng singitan ng non polar cap between suppressor grid & cathode .,  but screen grid is a bit fragile with a max of 150Vdc, so I will adhere to the spread sheet for longevity.

eto pala last project ko, EL84M pentode in triode mode, driver tube is 12AV6 high gain triode. Single ended design, class A, driving an Altec Lansing 3" driver with an SPL of 93dB

post  ko sana pics kaso not allowed pa daw ako magpost links(photobuket)
Million thanks sir Tony

[tony]

if you want to operate the 6P15P in triode mode, you can connect a 1k resistor to g3 and plate, and then 100 ohms from g2 to plate......

[???]

Makigulo rin ako dito.

Tnx sir efren, share na po tungkol dito.

[tony]

eto nga pala yung basing diagram ng dalawa:

[danny]

hi efren
welcome aboard, enjoy mo stay mo dito
madami ding mahilig sa tube dito
isa na ako, but i will leave the sonic qualities
to the listener, depende kasi iyan sa tao
may kaniya-kanyang taste iyan.
para sa akin, I like both tube and solid state.
I guess depende siguro sa pag kaka design or
pag kakagawa ng unit.  
Sir tony has a lot of tube projects
and really built well. As you can see, he really
take time to built it  
I wish I have a lot of time in my hand
to build one of this tube amps.
sana ma post mo din sir ang mga projects mo dito
I would definitley ask for you and sir tony's assistance
in the future 

thanks again and welcome po sa inyo

[efren]

 

hi efren
welcome aboard, enjoy mo stay mo dito
madami ding mahilig sa tube dito
isa na ako, but i will leave the sonic qualities
to the listener, depende kasi iyan sa tao
may kaniya-kanyang taste iyan.
para sa akin, I like both tube and solid state.
I guess depende siguro sa pag kaka design or
pag kakagawa ng unit. 
Sir tony has a lot of tube projects
and really built well. As you can see, he really
take time to built it 
I wish I have a lot of time in my hand
to build one of this tube amps.
sana ma post mo din sir ang mga projects mo dito
I would definitley ask for you and sir tony's assistance
in the future 

thanks again and welcome po sa inyo

Thanks a lot sir Danny, I met sir Tony personally as I have been to his place just recently and I can vouch that you can learn a lot from the man, he unselfishly shared a lot of knowledge about tubes & everything about electronics under the sun, oh by the way sir, hindi ako sarado sa solid state, one of my amp is designed by an Italian, Flavio Delipianne, a 5w/ch transistorized in class A mode driven by a DIY'ed 6BL8 tube line driver, as you can see mahilig po ako sa low wattage amplification, especially single ended designs, provided you MUST have a highly sensitive driver to truly enjoy the sonic qualities of these amps.

@ sir Tony,
thank you po sa added info, one of the box (unopened) have the pamphlet but it gives me a hard time figuring out which is which, kasi Cyrilic yun nakasulat puro Russian .

[efren]

Makigulo rin ako dito.

Tnx sir efren, share na po tungkol dito.

Yes sir JS, the more the merrier

[danny]

Thanks a lot sir Danny, I met sir Tony personally as I have been to his place just recently and I can vouch that you can learn a lot from the man, he unselfishly shared a lot of knowledge about tubes & everything about electronics under the sun, oh by the way sir, hindi ako sarado sa solid state, one of my amp is designed by an Italian, Flavio Delipianne, a 5w/ch transistorized in class A mode driven by a DIY'ed 6BL8 tube line driver, as you can see mahilig po ako sa low wattage amplification, especially single ended designs, provided you MUST have a highly sensitive driver to truly enjoy the sonic qualities of these amps.

@ sir Tony,
thank you po sa added info, one of the box (unopened) have the pamphlet but it gives me a hard time figuring out which is which, kasi Cyrilic yun nakasulat puro Russian .

can't wait to see your projects 

[tony]

@ sir Tony,
thank you po sa added info, one of the box (unopened) have the pamphlet but it gives me a hard time figuring out which is which, kasi Cyrilic yun nakasulat puro Russian

yup, so you can treat that tube as an EL84.......

[efren]

my EL84M single ended triode mode, speaker enclosure is also DIY, a 3" altec-lansing 93dB driver, 2w/ch

[efren]

my first tube amp, using 6F6G power tube driving a Philips 5" AD50600 in a modified Onkyo enclosure


the amp before using 6F6G tubes, originally use 6AR5 power tube & a 6u4GB rectifier tube
sorry for the low resolution, using only CP cam


my other tube project 12BA6 line stage, pagawa lang ito sa akin ng kaibigan ko

the owner while testing and auditioning his line stage(buffer/driver/pre-amp whatever you call it )

seems like he is happy with the performance

my experimental hybrid tube project, a 12AU7 tube driving a TDA1521 gainclone

[danny]

wow nice naman
kakainggit 
ang galing
thanks for posting 

[efren]

pasensya na po sir Danny CP cam lang ginamit ko, next time digicam na po

Sa mga nais sumubok maging "tubero", a few unsolicited safety tips po:

1. unlike BJT's or IC that operate on low DC voltage, vacuum tubes operate at a very high voltage, 300VDC-800VDC are common, some as high as 1kVdc that can knock you off your chair along w/ your projects , or worse will kill you . don't forget to install a bleeder resistor in the main filter caps to discharge that potentially dangerous voltage during servicing or tweaking.

2. do not remove speaker load while amp is operating, otherwise this is a short way to fry to a crisp the windings on those expensive output transformer, happened to me once

3. Vacuum tubes are very fragile, once you drop it & break the glass, then it's goodbye. The silvery coating on top or side of the envelope glass is a sign  that the vacuum state internally is excellent, but once there is a crack in the glass and the silver coating turns to powdery white, the tube is useless.

these are just a few tips that can save your life or your pocket   perhaps sir Tony would like to add some

[maldihtah13]

Waaah lalo akong naiinggit. Bakit kasi ngayon pa ako nawalan ng budget. Sana meron na rin me tube amp.

Sir Tony just wait I will try to get the items from you till may.

[efren]

one thing more.........

if ever you find an old tube amp (finding one is like finding a legendary yamashita treasure ), don't ever dare try to plug in the power outlet without first checking the power rating, filter capacitors and power transformer as expounded below:

1.power rating- 110v were common during the era of vacuum tubes, mostly imported brands such as RCA, PHILCO, VICTOR, GRUNDIG, etc.

2.filter capacitor-plugging a unit stashed for 60+years with ageing capacitors is like plugging a smoke generator machine, to be sure, replace all electrolytic caps with a new one w/ same or higher working voltage capacity.

3. power transformer-some during that era use a autotransformer type, others call it the "widow maker". wherein there is no secondary, the transformer ground or chassis is connected directly to one side of the power line , I have been victimized once by this type, nearly zapped the daylights out of me , so to be sure & safe use an isolation transformer or have that iron replaced with a secondary winding

[tony]

hi efren,
yes if you find even a tube type tv, there are lot's of parts you can get from it...

you can even assemble a guitar amp, using the vertical ouput transformer as ouput transformer for starters....

[tony]

Waaah lalo akong naiinggit. Bakit kasi ngayon pa ako nawalan ng budget. Sana meron na rin me tube amp.

Sir Tony just wait I will try to get the items from you till may.

no problemo, they are available when you need them...any particular circuit you have in mind?