I looked at the labels on my 1650E(s). They both show "15Watts, 30Hz - 30KHz". But what's also interesting is that above the MADE IN CANADA text its says 2014, and given when I bought them it would indicate it being a date code.
chokesrule, yours say 512 there, and that does seem strange.
Can anyone else with 1650E(s) check that number and chime in?
chokesrule, yours say 512 there, and that does seem strange.
Can anyone else with 1650E(s) check that number and chime in?
hmmmm will not know till I build. Have not bought the transformers yet..The ebay seller has 100% positive on 100s of sells and they from what seemed factory boxes and they weigh a ton...Here is a snip of a worrying pdf... Others say 30hz to 30khz..may be they changed the model specifiations...will have to wait and see..long wait as I am not a rich man
Attachments
I fired my amp over the weekend after getting the bias and CCS modules done. I’m having an issue I haven’t been able to solve and I need some help troubleshooting. The output is quite distorted.
I have double checked my build and it looks OK ( I’m very much a novice, so I could be missing something obvious). For the record, the power transorfmer was a little over the recommended voltage, producing 365V at B+ and I’m using 8 ohm taps on the output transformers.
I compensated for the higher voltage by changing the current set resistors in the Bias for 16R to 22R, changing the screen stop resistors from 15R to 270R. The feedback resistors was changed from 12K to 17K to compensate for using a 8 Ohm tap.
Here are voltages that I’m getting, the 2 channels are close.
EL84
Pin 7_______363V
Pin 3_______.6V
Pin 2_______-.5V
Pin 4,5______5.8V AC
Pin 9_______.15V
12AX7
Pin 1,6_______218V
Pin 3,8_______1.4V
Pin 4&5,9_______5.8V AC
-Brad
I have double checked my build and it looks OK ( I’m very much a novice, so I could be missing something obvious). For the record, the power transorfmer was a little over the recommended voltage, producing 365V at B+ and I’m using 8 ohm taps on the output transformers.
I compensated for the higher voltage by changing the current set resistors in the Bias for 16R to 22R, changing the screen stop resistors from 15R to 270R. The feedback resistors was changed from 12K to 17K to compensate for using a 8 Ohm tap.
Here are voltages that I’m getting, the 2 channels are close.
EL84
Pin 7_______363V
Pin 3_______.6V
Pin 2_______-.5V
Pin 4,5______5.8V AC
Pin 9_______.15V
12AX7
Pin 1,6_______218V
Pin 3,8_______1.4V
Pin 4&5,9_______5.8V AC
-Brad
Last edited:
Novice here, so bare with me.
What voltage should I be seeing on the screen grid of the EL84s?
Here is the schematic I'm working from and a close up of one channel on my build.
Attachments
Ian,
Thanks for your help on this, pretty amazimg that I only had one big mistake so far and no smoke.
As far as the sound, I was pretty tired by the time I figured out what was wrong and I called it a day.
I need to swap out the weak tubes I was using for testing for some nicer ones I have.
After that I'll bring it out of my shop and have a listen on some good speakers.
I'll let you know.
-Brad
Hi,
I'd like to build this amplifier but it seems I am limited by output transformers that I have. And they are 8k p-p (no UL taps) and 4k3 with UL tap. Output tubes on hand would be EL84, 6V6, KT88.
My first thought it to triode connected EL84, but its a deviation from the original..
Any advice is welcome.
LH/S
I'd like to build this amplifier but it seems I am limited by output transformers that I have. And they are 8k p-p (no UL taps) and 4k3 with UL tap. Output tubes on hand would be EL84, 6V6, KT88.
My first thought it to triode connected EL84, but its a deviation from the original..
Any advice is welcome.
LH/S
Ludwig,
You can use the 8K p-p wouthout U/L taps. AS per Yves original from which the Baby Hueys were derived. 6V6 would require the source follower buffers to meet max Rg1 specifications.
http://www.dissident-audio.com/PP_ECL86/Schema.gif
You could also use the 4K3 trannies with the U/L taps. For that use the schematic version with the MOSFET source follower buffers and run a quad of EL84 or 6V6 in parallel push pull. (Use 4 off source followers too).
Cheers
Ian
You can use the 8K p-p wouthout U/L taps. AS per Yves original from which the Baby Hueys were derived. 6V6 would require the source follower buffers to meet max Rg1 specifications.
http://www.dissident-audio.com/PP_ECL86/Schema.gif
You could also use the 4K3 trannies with the U/L taps. For that use the schematic version with the MOSFET source follower buffers and run a quad of EL84 or 6V6 in parallel push pull. (Use 4 off source followers too).
Cheers
Ian
bias testing
When I test my bias block (as below), at 6v i get 0.395v ie 39ma. As I raise the voltage, the current climbs steadily to 43ma at 12v....Is the bias block working ? Should the current be "exactly" the same from 6v to to 12v? Or the current rise with voltage I am seeing is it due to the accuracy of the multimeter and the amp will work fine? At all voltages the current remains constant. Alan
When I test my bias block (as below), at 6v i get 0.395v ie 39ma. As I raise the voltage, the current climbs steadily to 43ma at 12v....Is the bias block working ? Should the current be "exactly" the same from 6v to to 12v? Or the current rise with voltage I am seeing is it due to the accuracy of the multimeter and the amp will work fine? At all voltages the current remains constant. Alan
Attachments
Greetings all.
Newcomer here... especially interested in the Baby Huey design.
New to vacuum tubes, not new to electronics and physics (PhD).
I've tried to figure out many things by myself but still I think I'm in need of some advice. After going through some 60 pages of this thread, I think my head will blow out pretty soon. Looking for shortcuts
Much to learn, much to experiment.
But for kind of a crash-course I would go ahead and build this tiny amp and figure out the rest as I go.
BUT... The thing is, at the moment I do not have the mentioned tubes. That's why I'm thinking of replacing them with what I have, and that's why I would greatly appreciate a piece of advice from GingerTube.
In short, the question would be: could I use a 6P3S (not the "E" version) or 30P1S as a substitute for EL84, and either ECC84 or PCC189 for ECC803S? And if so, what modifications do you think I should make to the circuit? At list some guidelines, to be on the safe side. Optimizations later
Thanks a lot in advance.
Adrian
Newcomer here... especially interested in the Baby Huey design.
New to vacuum tubes, not new to electronics and physics (PhD).
I've tried to figure out many things by myself but still I think I'm in need of some advice. After going through some 60 pages of this thread, I think my head will blow out pretty soon. Looking for shortcuts
Much to learn, much to experiment.
But for kind of a crash-course I would go ahead and build this tiny amp and figure out the rest as I go.
BUT... The thing is, at the moment I do not have the mentioned tubes. That's why I'm thinking of replacing them with what I have, and that's why I would greatly appreciate a piece of advice from GingerTube.
In short, the question would be: could I use a 6P3S (not the "E" version) or 30P1S as a substitute for EL84, and either ECC84 or PCC189 for ECC803S? And if so, what modifications do you think I should make to the circuit? At list some guidelines, to be on the safe side. Optimizations later
Thanks a lot in advance.
Adrian
Greetings all.
Newcomer here... especially interested in the Baby Huey design.
New to vacuum tubes, not new to electronics and physics (PhD).
I've tried to figure out many things by myself but still I think I'm in need of some advice. After going through some 60 pages of this thread, I think my head will blow out pretty soon. Looking for shortcuts
Much to learn, much to experiment.
But for kind of a crash-course I would go ahead and build this tiny amp and figure out the rest as I go.
BUT... The thing is, at the moment I do not have the mentioned tubes. That's why I'm thinking of replacing them with what I have, and that's why I would greatly appreciate a piece of advice from GingerTube.
In short, the question would be: could I use a 6P3S (not the "E" version) or 30P1S as a substitute for EL84, and either ECC84 or PCC189 for ECC803S? And if so, what modifications do you think I should make to the circuit? At list some guidelines, to be on the safe side. Optimizations later
Thanks a lot in advance.
Adrian
I doubt that your choice of tubes would be workable in this design, but Ian will probably chime in the more knowledge.
For a beginner, and with the tubes you have, probably the design to look at would be the old Mullard 5-20. The 6P3S would work in place of the EL34 without much modifications. Output transformer would need to be around 6.6k primary impedance.
Your ECC84 and PCC189 are much lower gain than ECC83, and the PCC tube requires a different heater supply, so I would avoid that unless you want to provide an extra supply.
The ECC84 would work in the 5-20 circuit, but the overall gain will be much lower. As it is a high gain circuit anyway, that may be a good thing.
Use half of the ECC84 in place of the EF86 as well as the ECC83.
Overall then, you would need three ECC84 and four 6P3S to complete a stereo amp.
It is definitely not optimal and will have some distortion, but it will work.
