Hi All!
I wonder anyone has a good circuitry reference for a Single Ended configuration of a pair of EL153?
I have an SE AMP running 1 EL153 in Single Ended configuration. It was made DIY by a friend of mine around 12 years ago.
It has been given a change in power transformer and two EZ80 in the power supply for the input stage PCC88, and the pair of EL153 respectively.
However, no matter what my friend has done, since the power transformer change, the amp has been giving loud hum sound, like a combination of 50Hz signal with multiple high order intermodulation noises above it. I hate to trash the amp for its noise, but I have now where to do
I wonder anyone has a good circuitry reference for a Single Ended configuration of a pair of EL153?
I have an SE AMP running 1 EL153 in Single Ended configuration. It was made DIY by a friend of mine around 12 years ago.
It has been given a change in power transformer and two EZ80 in the power supply for the input stage PCC88, and the pair of EL153 respectively.
However, no matter what my friend has done, since the power transformer change, the amp has been giving loud hum sound, like a combination of 50Hz signal with multiple high order intermodulation noises above it. I hate to trash the amp for its noise, but I have now where to do
Can you be more specific about the xformer "change"? Is the "new" xformer the same as far as # of windings, voltages and current ratings are concerned?
The schematic of your amp is essential for fault finding. I suspect the hum is caused by improper grounding - check if all leads are connected, tubes are properly sit in sockets etc.
The schematic of your amp is essential for fault finding. I suspect the hum is caused by improper grounding - check if all leads are connected, tubes are properly sit in sockets etc.
Hi TBL,
probably your amp are going to oscillate in the radio frequency range. The EL153 ist a RF output valve designed to operate on frequencies up to 150 MHz. Did you checked it with an oscilloscope?
If the circuit behave like this, insert grid stoppers or/and plate chokes.
Here are the original Telefunken spec sheet(german language):
http://www.mif.pg.gda.pl/homepages/frank/sheets/118/e/EL153.pdf
This valve were widely used in shipboard transmitters & and in base stations of land mobile radio services.
73
probably your amp are going to oscillate in the radio frequency range. The EL153 ist a RF output valve designed to operate on frequencies up to 150 MHz. Did you checked it with an oscilloscope?
If the circuit behave like this, insert grid stoppers or/and plate chokes.
Here are the original Telefunken spec sheet(german language):
http://www.mif.pg.gda.pl/homepages/frank/sheets/118/e/EL153.pdf
This valve were widely used in shipboard transmitters & and in base stations of land mobile radio services.
73
Funker,
I know the EL153 is different from its brother EL153 in its frequency operating frequency range. With the Audion Sterling in mind when designing a SE amp, My friend chose the EL153 for its wide bandwith. The first PSU was a conventional design, until the current draw was so high it burnt out in just two years' time.
This is now replaced by a toroidal power transformer. That was when the loud hum bagan. I disconnected the ground wire running to the line power plug. This helped reduce the IM noise above the 50HZ-ish noise which is staying decidly.
I do not have the schematic now but I think I can take some pictures if you do not mind taking a look see.
Thanks in advance!
I know the EL153 is different from its brother EL153 in its frequency operating frequency range. With the Audion Sterling in mind when designing a SE amp, My friend chose the EL153 for its wide bandwith. The first PSU was a conventional design, until the current draw was so high it burnt out in just two years' time.
This is now replaced by a toroidal power transformer. That was when the loud hum bagan. I disconnected the ground wire running to the line power plug. This helped reduce the IM noise above the 50HZ-ish noise which is staying decidly.
I do not have the schematic now but I think I can take some pictures if you do not mind taking a look see.
Thanks in advance!
EL153 tube proposing this project in SE configuration and output power of 15W.
The design is complete and voltages and currents are marked important points.
EL153 power dissipation for final tube is 30W and is located beneath the anode dissipation hyperbole.
For EL153 tube can go casual with power dissipation up to 40W.
A draft tube must be done with care and attention to the points table and routes filaments, and location of transformers on the chassis must be done properly.
Output transformer has a 10K Ra and the practical problems will not, of course, be done with air gap so as not to saturate the core.
The design is complete and voltages and currents are marked important points.
EL153 power dissipation for final tube is 30W and is located beneath the anode dissipation hyperbole.
For EL153 tube can go casual with power dissipation up to 40W.
A draft tube must be done with care and attention to the points table and routes filaments, and location of transformers on the chassis must be done properly.
Output transformer has a 10K Ra and the practical problems will not, of course, be done with air gap so as not to saturate the core.
Attachments
TBL, some pictures would be useful to diagnose the source of the noise - if the electrical compatibility is assured, it remains the possibility of electromagnetic induced noise, how is the new transformers position relative to the tubes? Did it change a lot? If yes, try to enclose the transformer in an iron pot, even temporary, trying to listen to the difference...
On the other hand...do you have separate heater windings for the EZ80? I understand you added them lately...if no, that's the noise source for sure - the heater windings must be separate for the rectifier tubes, even for those with indirect heating...the cathode-heater leakage is not to be neglected...if your power transformer hasn't separate winding for the rectifiers, get rid of the EZ80 and try using simple diodes - eventually with some resistors in series to compensate the voltage gain - about 50-100 ohms could be ok.
***
Because I have a pair of NOS EL153 made by Telefunken in Germany, I'm planning to build this summer the amplifier design proposed by LAZAROIU, stay tuned!
On the other hand...do you have separate heater windings for the EZ80? I understand you added them lately...if no, that's the noise source for sure - the heater windings must be separate for the rectifier tubes, even for those with indirect heating...the cathode-heater leakage is not to be neglected...if your power transformer hasn't separate winding for the rectifiers, get rid of the EZ80 and try using simple diodes - eventually with some resistors in series to compensate the voltage gain - about 50-100 ohms could be ok.
***
Because I have a pair of NOS EL153 made by Telefunken in Germany, I'm planning to build this summer the amplifier design proposed by LAZAROIU, stay tuned!
GU50 alternative...
Yes, it is, but primary I don't like the aspect of this tube and secondary I trust more the TFK quality than the soviet-russian made GU50.
Still, it could be a good idea for those who don't have the quite rare EL153...
As far as I know, LAZAROIU has the simulated schematic also for the GU50 SE version, you can search the GU50 topics...
Yes, it is, but primary I don't like the aspect of this tube and secondary I trust more the TFK quality than the soviet-russian made GU50.
Still, it could be a good idea for those who don't have the quite rare EL153...
As far as I know, LAZAROIU has the simulated schematic also for the GU50 SE version, you can search the GU50 topics...
EL153 Schematic
Hello everyone!
I confirm that the circuit posted by Mr. Lazaroiu is very well designed and the sound is incredible...comparing with my other SE amplifiers, one with EL84 and one with russian 6P3S. The transformers built on old russian cores (B/W TV Rubin 102A, the power transformers, 18cm2 section) are great.
Mr. Lazaroiu has a good name here, in Romania, on winding transformers for diy tube projects.
I will come back with a picture gallery when the case will be finished...by now I put just one, to have an idea.
The only modification/deviation from the original simulated circuit is the cathode resistors of EL153, I used a wire-wound rheostat and the exact values were 770 and 800 ohms, that gave the anode current specified. With 540 ohms it was around 65mA, a little too much...
Hello everyone!
I confirm that the circuit posted by Mr. Lazaroiu is very well designed and the sound is incredible...comparing with my other SE amplifiers, one with EL84 and one with russian 6P3S. The transformers built on old russian cores (B/W TV Rubin 102A, the power transformers, 18cm2 section) are great.
Mr. Lazaroiu has a good name here, in Romania, on winding transformers for diy tube projects.
I will come back with a picture gallery when the case will be finished...by now I put just one, to have an idea.
The only modification/deviation from the original simulated circuit is the cathode resistors of EL153, I used a wire-wound rheostat and the exact values were 770 and 800 ohms, that gave the anode current specified. With 540 ohms it was around 65mA, a little too much...
An externally hosted image should be here but it was not working when we last tested it.
EL153 Schematic
They will be here...as soon as I have time to finish the connections and some mechanical fittings.
I have to state also that Mr. Lazaroiu has good skills in designing and analysing the tube amplifiers schematics...this one is his creation, made from scratch...only by simulating it and based on the datasheet published by Telefunken.
I am very happy with this design, I have built several tube amplifiers, but this one seems to be my first one pretending to touch the high-end level. I will do some osciloscope tests when I'll can, but for my ears it sounds near perfection...no flaws heard till now...at least I can say I hear the tiniest details, heard by now only on headphones...
And here is a night-view, the green spots are from my computer's monitor.
They will be here...as soon as I have time to finish the connections and some mechanical fittings.
I have to state also that Mr. Lazaroiu has good skills in designing and analysing the tube amplifiers schematics...this one is his creation, made from scratch...only by simulating it and based on the datasheet published by Telefunken.
I am very happy with this design, I have built several tube amplifiers, but this one seems to be my first one pretending to touch the high-end level. I will do some osciloscope tests when I'll can, but for my ears it sounds near perfection...no flaws heard till now...at least I can say I hear the tiniest details, heard by now only on headphones...
And here is a night-view, the green spots are from my computer's monitor.
An externally hosted image should be here but it was not working when we last tested it.
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Thank you...the blue glow is almost gone, it was visible only in the first few hours of listening, and this barely in the dark, the picture is taken with tripod with long exposure time, for the "eye candy" effect some tube lovers are searching...
The amplifier is almost finished, the lack of "diy" time is the reason I am so late with the final photos.
The amplifier is almost finished, the lack of "diy" time is the reason I am so late with the final photos.
I promissed two years ago to come back with pictures of my finished amplifier...here they are:
I works flawless since then, only the EF80 were changed, in the begining I used some old TV-scraped tubes, now I have NOS Tungsram EF80. I was happier with the old Toshiba tubes, 6BX6, but one of them developed some discharges between electrodes...it's gone.
The aluminium round plate was mounted because of my diy mistake - I tried to carve the inner side of the case to make space for the potentiometer's shaft - the tool I used was surprisingly quick...now I like it more this way...even if it was firstly intended as a patch...
I works flawless since then, only the EF80 were changed, in the begining I used some old TV-scraped tubes, now I have NOS Tungsram EF80. I was happier with the old Toshiba tubes, 6BX6, but one of them developed some discharges between electrodes...it's gone.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
The aluminium round plate was mounted because of my diy mistake - I tried to carve the inner side of the case to make space for the potentiometer's shaft - the tool I used was surprisingly quick...now I like it more this way...even if it was firstly intended as a patch...
EF80 was mr. Lazaroiu's choice but they sound good and don't seem to suffer from the voltage.
I won't waste EL84 on that, but instead I intend to use EL83 or EL803S, in this application the matter is the voltage and not the anode power, so these tubes fit very well...I have schematics drawn for both tubes...I will be back when I find them. This was before I got NOS EF80 - it was an intention to replace my used EF80's. I'm also curious about the differences, if there are any...
I won't waste EL84 on that, but instead I intend to use EL83 or EL803S, in this application the matter is the voltage and not the anode power, so these tubes fit very well...I have schematics drawn for both tubes...I will be back when I find them. This was before I got NOS EF80 - it was an intention to replace my used EF80's. I'm also curious about the differences, if there are any...
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