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Electronic Transformer heating for the gm70 test

72.211.153.103
Posted on January 28, 2017 at 08:21:43
used-hifi
Audiophile

Posts: 1100
Location: Surprise AZ
Joined: March 18, 2003



Lots of discussions on these type of electronic transformers as a good alternative to the much more expensive to implement regulators

upon first listening they made the music sound muffled, then in about 20 mins it all came together somehow, now from these initial experiments I can clearly see why anyone would go this way, these things are small! very easy to implement (cheap) and make the music sound good


I needed about 20v for the gm70 so i added enough capacitance "1000uf" to the bridge rectifier to get about 20v 19.6 actually on the output, I did order more proper caps 1200uf 200v in a single cap these here that i have are 4700uf 35v wired in series no need to wind more turns on the transfomer.

some things I do not like I can clearly hear this unit oscillate at 37kc! so i will need to put it back into its enclosure, Yes I have bat hearing

the other thing I dont like is there is no ramping up its voltage it all comes on the instant you plug it in, so no slow or soft start maybe add a mov?

I am reluctant to say that these are as good as rod's regulators but they are prob good enough more testing on proper speakers will tell more of the story, my large fulton speakers will play way out hi 80kc!, so if there is something I am missing with my little fulton speakers these will tell the story.

I am familiar with real musical instruments

so here is What I listen for:

Proper form and function the sound from various instruments, bass drum, brass instruments all these have a certain sounds and brass has a certain peculiar attack along with is beautiful brass sheen when played in the upper registers, Piano need to sound right its a percussive instrument


Lawrence

p.s. a few Thanks go out to defbykhorns and RayP Thanks for all your help.

 

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RE: Electronic Transformer heating for the gm70 test, posted on January 28, 2017 at 17:50:25
used-hifi
Audiophile

Posts: 1100
Location: Surprise AZ
Joined: March 18, 2003
 For anyone who cares :)

I have done some more testing I wanted to see what the output on the amplifier looks like as far as hum well there is hum allright 400mv of 37kc hum!!!!!!!!!!! WTF??

IMO totally unacceptable and if i would have known about this before hand I would have NEVER even tried this idea

even though I could hardly detect this hum except for the unit itself does make hi freq (37kc) noise that drives me crazy, so when I seen this it is a deal breaker for me IMO this is not HIFI this is LowFi

Thank the good Lord that we have something that IS HIFI! Rod Coleman Regulators

what to do with these now LOL



Lawrence

 

RE: Electronic Transformer heating for the gm70 test, posted on January 28, 2017 at 20:18:25
Triode_Kingdom
Audiophile

Posts: 10037
Location: Central Texas
Joined: September 24, 2006
 The transformers in my SETs run at 60-66kHz. Hum can be nulled with a pot, just like any other AC-driven filament. I wouldn't even consider using a DC system.


 

RE: Electronic Transformer heating for the gm70 test, posted on January 28, 2017 at 21:27:31
used-hifi
Audiophile

Posts: 1100
Location: Surprise AZ
Joined: March 18, 2003
 so let me see you want to use this state of the art switcher (newer technology) and then use old crappy hum pot in the direct signal path to null out the fundamental?!, you still have noise left because the null does not rid of the harmonics!

no but seriously TK unless you have used what I am using here, How would you know one way or the other what might sound better? or more importantly work better??

At least I have tested both! you wont even think of using DC with regulator why not? cost??

anyways I am LED Biasing the gm70 how should I implement your way?


Lawrence

 

YMMV, posted on January 29, 2017 at 05:14:15
RayP
Audiophile

Posts: 727
Location: Maryland
Joined: June 30, 2005
 I suppose that is why we use this acronym a lot in our hobby.

Clearly your hearing abilities are different from mine. I just checked and at age 69 I can hear up to 13 khz and that is it. Back when I was aged 35 I could hear 20 khz. Your hearing is well beyond what most people hear, so obviously AC heating at 37 khz is not a solution for you.

However, it may still be a solution for others with less phenomenal hearing. My original reason for trying the method was reduced weight. For others, reduced size. For some, reduced cost. Some may prefer AC to DC. If those factors are not important to you then the RC regulators are a highly regarded safe option.

That is the beauty of our hobby. We can make decisions that suit our own particular needs, restrictions, experiences and biases.

ray

 

RE: YMMV, posted on January 29, 2017 at 09:41:18
used-hifi
Audiophile

Posts: 1100
Location: Surprise AZ
Joined: March 18, 2003
 Sorry Ray there is no way this should be acceptable, you cannot rational away the simple "FACT" that there is crap load of 37kc hum on the output, if you really think this is acceptable I feel for ya.... that is I feel sorry for you.

if your hearing is so low in quality why bother with this at all? might as well just get a nice clean small digital amplifier and be done with it? these have all kinds of stuff on the output that you cannot hear anyways right?


I also feel like i just flushed 20 dollars down the toilet that i will never get back, no biggie just money :)


Lawrence

 

RE: Electronic Transformer heating for the gm70 test, posted on January 29, 2017 at 10:09:45
deafbykhorns
Audiophile

Posts: 1067
Location: Florida
Joined: October 17, 2003
 First, you need to reduce oscillating windings and you will get 65khz
Second, you need to still add a hum pot to null the HV
Third, add 3-4 windings to get your 20v

 

RE: YMMV, posted on January 29, 2017 at 10:57:42
vetmedrobert@gmail.com
Audiophile

Posts: 453
Location: Ontario
Joined: September 20, 2007
 It is a well accepted, scientifically proven fact that the range of hearing for humans is limited to 20 Hz to 20kHz. I just turned 60 and consider myself fortunate that I can hear out to 12kHz. I will not take your advice and listen to a small digital amp since I get a lot of pleasure from building my own non-digital tube amps. Assuming you are fortunate enough to live into old age you too will suffer impairment to your hearing that will make this ridiculous discussion of being able to hear 37 kHz signals rather pointless.

 

Lighten Up, posted on January 29, 2017 at 11:23:24
Triode_Kingdom
Audiophile

Posts: 10037
Location: Central Texas
Joined: September 24, 2006
 "if your hearing is so low in quality why bother with this at all? "

I think it's pretty clear you don't know how to use this technique. People might be more willing to guide you through it if you didn't find it necessary to insult everyone who responds. And on this subject of hearing 37kHz ripple - I didn't find anyone with that capability in the Guinness book. Maybe you should apply.



 

RE: Lighten Up, posted on January 29, 2017 at 11:45:44
hennfarm
Audiophile

Posts: 535
Location: Oregon
Joined: October 8, 2008
 Another know-it-all who after 5posts reveals they don't understand some of the fundamentals....:*). JH

 

RE: Lighten Up, posted on January 29, 2017 at 12:08:53
used-hifi
Audiophile

Posts: 1100
Location: Surprise AZ
Joined: March 18, 2003
 It took me to post some neg thoughts about you guys idea to finally get someone to post, you all must love dramma

I feel insulted by this really great idea that you guys posted but neglected to leave out that you will have half a watt of hi freq on its output!!! even if i null out the fundamental there will still be harmonics and all the the nice harmonics on the line itself.


its somewhat my fault as I just took it as THIS IS THE WAY TO DO IT and not think for myself, never again!


you guys here are not up to speed, I think DIYaudio forum will suit me much better, as these guys HAVE A CLUE

no need to rant anymore good luck with all your HI freq heating LOL

I will stick to THE CORRECT WAY to heat hi mu tube


Lawrence




 

RE: Lighten Up, posted on January 29, 2017 at 13:42:37
Triode_Kingdom
Audiophile

Posts: 10037
Location: Central Texas
Joined: September 24, 2006
 Good luck to you Lawrence. Don't forget to tell the little Stalins running that forum how awful we are.

 

RE: Lighten Up, posted on January 29, 2017 at 15:05:53
hennfarm
Audiophile

Posts: 535
Location: Oregon
Joined: October 8, 2008



 

RE: Lighten Up, posted on January 29, 2017 at 17:11:55
vetmedrobert@gmail.com
Audiophile

Posts: 453
Location: Ontario
Joined: September 20, 2007
 An electronic scale. Likely generates significant audible amounts of 37 kHz...

 

Not to worry..., posted on January 30, 2017 at 08:51:54
PakProtector
Audiophile

Posts: 12360
Joined: May 14, 2002
 If I ever bought a SE opt I would be even more certain that you that I have flushed some large amount of money.

My PP DH stuff is all 60 cps AC, and it is quite quiet, thanks to a hum pot and filament winding for each tube.
cheers,
Douglas

Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.

 

RE: YMMV, posted on February 2, 2017 at 09:06:46
amnesiac
Audiophile

Posts: 717
Joined: August 21, 2002
 love trumps hate love trumps hate love trumps hate

you sound like a product of the american university system lol

 

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