I finish my project ...an pp with 6c33c....this is the schematic:
http://translate.google.com/transla.../Leserbriefe/Roessler-PP-Neu/Beschreibung.htm
But...I have a problem....the noise...is not "humm"....is "fissss".
I replace some C's.....more close to 470uf/450V and the little "hummm" was disappeared.....but I still have that "fisss".All the ground wires was strictly the same like in the original project.From each plate is only one single ground wire,exactly like is in the pictures,and all connected in only one point,to the chasis.
That "fisss" is hear by some 7...10cm from the speaker(an 85db/m speaker).....and it's fine ........but when I connect an 96db/m speaker,the situation is not so good.The noise is detectable from about 1,8 meters.It's only "fisss" but it is and is not depend from volume level.
So ....do you have any ideeas how can I remove that ?
Many thanks.
http://translate.google.com/transla.../Leserbriefe/Roessler-PP-Neu/Beschreibung.htm
But...I have a problem....the noise...is not "humm"....is "fissss".
I replace some C's.....more close to 470uf/450V and the little "hummm" was disappeared.....but I still have that "fisss".All the ground wires was strictly the same like in the original project.From each plate is only one single ground wire,exactly like is in the pictures,and all connected in only one point,to the chasis.
That "fisss" is hear by some 7...10cm from the speaker(an 85db/m speaker).....and it's fine ........but when I connect an 96db/m speaker,the situation is not so good.The noise is detectable from about 1,8 meters.It's only "fisss" but it is and is not depend from volume level.
So ....do you have any ideeas how can I remove that ?
Many thanks.
I removed all the "humm"...simply by replace some values of filters and "pi" filters but that not reduce the "fisss".That noise is not a problem for the 85-87db speakers......but for the 95-100 db is a pain in the a**.
Tomorow I want to work a little on the 400V power supply ...to replace regulator with fast switching diodes with parallel 4,7nf.....and see what happens.
If you have any experience in that issue please explaine.
I know .....the problems with noise rezistors.....but maybe that power supply was not sufficient filter....
Any ideeas.......?
Tomorow I want to work a little on the 400V power supply ...to replace regulator with fast switching diodes with parallel 4,7nf.....and see what happens.
If you have any experience in that issue please explaine.
I know .....the problems with noise rezistors.....but maybe that power supply was not sufficient filter....
Any ideeas.......?
Did you run it without the pre-tubes? Did it still "fisss"? The power supply for the final stage looks fine to me-quite some effort here for PP - but maybe you hear some "switching" noise from the rec diodes?
Anyway - would also eMail Ernst directly and ask him, if nothing else,
cheers,
Marcus
Anyway - would also eMail Ernst directly and ask him, if nothing else,
cheers,
Marcus
In regards to the input noise you are experiencing, are you using high efficiency loudspeakers?
Is it just a simple hiss (more or less white noise) or does it include lower frequency rumbling, burbling, popping and the like?
If you are using carbon resistors as plate loads you may want to reconsider.. MF and non-inductive wirewound are much quieter.
Also some 6SL7 are quieter than others, so you may want to try some different brands.
I have rarely used a commercial rfi filter that did not seem to have a negative impact on the sound, (And I'll admit I don't know why) yet by the same token similar devices I've built or borrowed using air core inductors and low esr/esl film caps seemed helpful in electrically noisy environments.
Is it just a simple hiss (more or less white noise) or does it include lower frequency rumbling, burbling, popping and the like?
If you are using carbon resistors as plate loads you may want to reconsider.. MF and non-inductive wirewound are much quieter.
Also some 6SL7 are quieter than others, so you may want to try some different brands.
I have rarely used a commercial rfi filter that did not seem to have a negative impact on the sound, (And I'll admit I don't know why) yet by the same token similar devices I've built or borrowed using air core inductors and low esr/esl film caps seemed helpful in electrically noisy environments.
Yes...I have 97db speakers.The noise is clean ...no pups or everything.
I replace some rezistors but not all from the tubes plate and the noise(that fiss and a little 50hz from the mains) is detectable only from 25cm between ear and speaker.Is a poor noise but is.From 30cm distance the noise disappeared.I tryed with 86db speakers and is hard to hear that noise...only 1 or 2cm from tweeter.
Also I replace 6sl7 with other brands and yes.....some of them are quieter then others.
I think ...to every tube amp is that noise...more or little but is.
Put your ear close to the speaker and tell me from what distance is the noise detectable.
Do you think that noise from mentioned distance is normal?
Thanks.
I replace some rezistors but not all from the tubes plate and the noise(that fiss and a little 50hz from the mains) is detectable only from 25cm between ear and speaker.Is a poor noise but is.From 30cm distance the noise disappeared.I tryed with 86db speakers and is hard to hear that noise...only 1 or 2cm from tweeter.
Also I replace 6sl7 with other brands and yes.....some of them are quieter then others.
I think ...to every tube amp is that noise...more or little but is.
Put your ear close to the speaker and tell me from what distance is the noise detectable.
Do you think that noise from mentioned distance is normal?
Thanks.
The old maxim was if you couldn't hear it from 30cm distance not to worry about it, and yes some noise is normal - and with speakers with 97dBSpl efficiency even very small quantities of noise will be audible at some distance. My current speakers are Onkens + mid and tweeter horns and are around 98dB efficient, my previous pair were almost 103dBspl so I know a little about noise issues.
From what you have described I don't believe you have a problem at all. So enjoy your new amplifier!
From what you have described I don't believe you have a problem at all. So enjoy your new amplifier!
"ALELUIA"......you are the first HONEST PERSON,who tell me the truth.
All the guys tell me........"ohh...but I don't have any noise....my amp is crystall,absolutly no noise...not even with ear attached to the tweeter".....
I heared Audio Note monoblocs and yes ...they have noise.
So...I'm satisfyed now,much on that because you tell me the reality.
Many thanks KEVINKR......seems you are a very vertical person.I read a little on your website...and I saw a lot of work there.Definitly you have previous experience ....and it seems a solid one.
And.....I want to ask you something.....I hope not bother you.....I have two drivers 96db (it's Supravox 215rtf Bicone...qts.0,53).....what enclosure do you think it's fits well for them?
Some tell me an open baffle it will be more close to that qts,others an tqwt ......Some of them tell me that tqwt on their's website doesn't fit well with them.
Maybe I will write details on your e-mail if you want to guide me.
Again....thanks and best regards.
All the guys tell me........"ohh...but I don't have any noise....my amp is crystall,absolutly no noise...not even with ear attached to the tweeter".....
I heared Audio Note monoblocs and yes ...they have noise.
So...I'm satisfyed now,much on that because you tell me the reality.
Many thanks KEVINKR......seems you are a very vertical person.I read a little on your website...and I saw a lot of work there.Definitly you have previous experience ....and it seems a solid one.
And.....I want to ask you something.....I hope not bother you.....I have two drivers 96db (it's Supravox 215rtf Bicone...qts.0,53).....what enclosure do you think it's fits well for them?
Some tell me an open baffle it will be more close to that qts,others an tqwt ......Some of them tell me that tqwt on their's website doesn't fit well with them.
Maybe I will write details on your e-mail if you want to guide me.
Again....thanks and best regards.
Hi Felixx,
I'm extremely flattered by the complements, however I'm not an experienced speaker designer having researched and designed only two speaker systems in my life. The Onkens are a great success, but I built based on a lot of good advice garnered right here, and probably more than a little good luck and instinct..
There are several people in the loudspeaker forums who are knowledgeable and honest about their level of experience. Dave (frugalphile), Panomaniac and GM have lots of loudspeaker design experience.
Vance Dickason's book is another source of accurate and useful speaker design information.
I really can't say whether OB or TQWT would be better with these drivers.
I'm extremely flattered by the complements, however I'm not an experienced speaker designer having researched and designed only two speaker systems in my life. The Onkens are a great success, but I built based on a lot of good advice garnered right here, and probably more than a little good luck and instinct..
There are several people in the loudspeaker forums who are knowledgeable and honest about their level of experience. Dave (frugalphile), Panomaniac and GM have lots of loudspeaker design experience.
Vance Dickason's book is another source of accurate and useful speaker design information.
I really can't say whether OB or TQWT would be better with these drivers.
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