Topic: 6BQ5/7189 Power pentodes

[efren_]

Has anyone tried this particular Tube? I remember seeing them inside my father's Grundig in my high school days, I was not really interested in audio or electronics way back then, so I remember hearing them just as ordinary, but he enjoys listening to it after work with his stack of vinyls playing Johnny Mathis, Ella Fitzgerald, and other oldies 33rpm's. 

Seems popular, lots of sources and costs cheaper than those big bottles, has higher plate voltage handling than my 6F6's. I'm planning to build(my wife's not gonna like this! ) a single ended switchable between triode/pentode mode. Any feedback is of a great help.

[JojoD818]

It's a sub for an EL84 if I remember right. Panalo yan sir... 

[efren_]

It's a sub for an EL84 if I remember right. Panalo yan sir... 

 Thanx for the input sir Jo, now it's all up to the availability of funds

[edrel sison]

here was my journey with the 7189s. this is a very good tube.
http://www.pinoydvd.com/index.php/topic,77243.0.html

efren i would think this would be a very cheap amp. you can build them alongside a cold bottle of beer.

[efren_]

here was my journey with the 7189s. this is a very good tube.
http://www.pinoydvd.com/index.php/topic,77243.0.html

efren i would think this would be a very cheap amp. you can build them alongside a cold bottle of beer.

Hi sir Edrel, yes, AMX offered a matched pair and a choice between Japs & European (National & Telefunken).
Pwede po ba dito yun OPT na ginamit ko sa 6F6? Specsheets recommend 5.2K plateload. When i'm ready i'll send you pm or sms.

Btw, I've discovered that eliminating global feedback in my 6F6 SE improved the sonic quality much more., changing also the bypass electrolytic caps to non-polar in the cathode of driver tube makes it even better.
Just want to share the info

[edrel sison]

efren get the telefunks..
swak na swak yang OPT ko sa 7189 but then you can opt for a bigger size for better lows.

just make a test bench first and borrow your 6F6 OPTs and see how.

tip: invest heavily on your PSU, (Z11 PTX & chokes, oil cans filter caps) you wont regret it..

[efren_]

efren get the telefunks..
swak na swak yang OPT ko sa 7189 but then you can opt for a bigger size for better lows.

just make a test bench first and borrow your 6F6 OPTs and see how.

tip: invest heavily on your PSU, (Z11 PTX & chokes, oil cans filter caps) you wont regret it..

Thanks sir Edrel, now the excitement is beginning to wake up again

[edrel sison]

if you will need those oil cans and oil couplings let me know.

[JojoD818]

tip: invest heavily on your PSU, (Z11 PTX & chokes, oil cans filter caps) you wont regret it..

+1 on this

the tubes are just half of the story, the other half are the irons...

[efren_]

if you will need those oil cans and oil couplings let me know.

I was wondering sir Edrel, are they different from electrolytics? are they non polar caps commonly used as industrial motor starting caps, then they must be really huge 

[edrel sison]

efren, huge difference in sound and performance. you may want to try it. ano B+ mo?

[rony]

Maganda 6bq5, one of my favorite output tubes. An easy to drive bookshelf will do the job for this tubes.

[s2kov]

ayaw mo na 2a3?

Maganda 6bq5, one of my favorite output tubes. An easy to drive bookshelf will do the job for this tubes.

[JojoD818]

ayaw mo na 2a3?

Andy, pano kasi meron siya nito hehehe... 

[s2kov]

kaya pala eh!

pano na yung Quad?

[JojoD818]

pero malabo mapabayaan yun 2a3...  peyborit ni rony yun eh! 

[s2kov]

ayun oh!

pero malabo mapabayaan yun 2a3...  peyborit ni rony yun eh! 

[rony]

ayaw mo na 2a3?

Oy oy oy andy nipis yan 2a3! Nyhahaha Gusto ko nga ipa makeover yun kaha nun. Nag tatagihawat yun chrome plating niya due to ageing na siguro oks ba yun balayong?

[rony]

Andy, pano kasi meron siya nito hehehe... 

Pssst akin na lang yan. Amoy luma na yan.

[JojoD818]

Pssst akin na lang yan. Amoy luma na yan.

yun nga yun sir, amoy pa lang vintage na hahaha 

[s2kov]

ano yung balayong?

ganitong chassis na gamitin mo!

Oy oy oy andy nipis yan 2a3! Nyhahaha Gusto ko nga ipa makeover yun kaha nun. Nag tatagihawat yun chrome plating niya due to ageing na siguro oks ba yun balayong?

[efren_]

efren, huge difference in sound and performance. you may want to try it. ano B+ mo?

within specs lang po ng 6bq5, 300V yata according to NJ7P.
so 230 x 1.414=325volts, minus  voltage drops i think that's ok.
 
btw sir i have a 145uF/400v AC caps, try ko nga sa 6F6 amp ko.

[edrel sison]

huge indeed efren, but what the heck? it will look and sound good anyway..
anong brand ng AC caps mo? the best is ASC daw..

[efren_]

huge indeed efren, but what the heck? it will look and sound good anyway..
anong brand ng AC caps mo? the best is ASC daw..

Robinson Nuggent, manufactured by EUN SUNG(Korea?) almost as big as a spray paint can without the top cap. 450V pala sir. I tried it this morning, totoo nga as the "negligible" rough edges smoothen out.

[edrel sison]

not so bad efren..if you can have those more expensive GEs, CSCs and AEROVOXs give it a try.

[mhore]

Pre Efren,

May you rest in peace. Kung saan ka man ngayon, im sure ma-mimiss ka ng mga followers mo dito.
One thing for sure, your thread/post here will still remain.

[wackiedoodle]

my sincere condolences to the family of sir efren...

[JojoD818]

Pre Efren,

May you rest in peace. Kung saan ka man ngayon, im sure ma-mimiss ka ng mga followers mo dito.
One thing for sure, your thread/post here will still remain.

Uy why? What happened to sir Efren?

[ATJr.]

Efren succumb to a stroke, his third, he was suffering from hypertension, his wife texted me, i was at his wake, this was several months ago na.....he is surely missed, Dandy from the other forum paid him a tribute in his website...

[JojoD818]

Thanks tony, I wasn't aware of what happened. Our sincere condolences to his family.