• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

EL84 Amp - Baby Huey

New EL84 Baby Huey PCB !

Hello Baby Huey Builders,

As there were several demands for the EL84 version and I was not satisfied with my first layout, I decided to rework the EL34 PCB with 9-pin socket instead of the octal socket :) I take advantage of this new layout to make some cosmetic changes but beware that this design HAS NOT BEEN TESTED :bomb:

Some knowledgeable people can have a look at the schema (which has not been modified, except the replacement of the input pot by a resistor) and the PCB which has been significantly modified (not only the tubes sockets) !

If you feel confident with that, I can post the Gerber files and you can produce it at your risk :grumpy:

I may also change the MOSFET because the ZVN0545A is obsolete and there is better devices like the STQ3N45K3 but it is not pin compatible :mad:

Let see if there is still interest first...:D

Best regards,
Marc
 

Attachments

  • Schema EL84 Baby Huey Rev 1.2.pdf
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  • PCB EL84 Baby Huey Rev 1.2.png
    PCB EL84 Baby Huey Rev 1.2.png
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Hello All,

Since there seem to be definitively some interest for the EL84 Baby Huey version, I have modified the PCB to accept the same MOSFET than the one used in the EL34 Baby Huey, the STU9HN65M2, to replace the obsolete and less powerful ZVN0545A. Now the EL84 version is very similar to the EL34 version !

If there is no other comments, I can put the Gerber files on the forum and may be someone can make a GB but I repeat that I nave not tested personally this version and even if it is very close to the EL34 version build and tested by tenths of people there could always be an error somewhere :scared:

Let me know if you find somethings strange on this layout ?

Cheers,
Marc
 

Attachments

  • Schema EL84 Baby Huey Rev 1.4.pdf
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  • PCB EL84 Baby Huey Rev 1.4.png
    PCB EL84 Baby Huey Rev 1.4.png
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EL84

Hello Marc

Nice job revising the EL84 schematics. The only change I change I would suggest is the drawing's reference to a typical output transformer. I would suggest EDCOR CXPP-10-MS-10K (10 watt, 10K). I have 2 and they are very nice.

With your guidance, I am prepared to order a sample set of these boards, try them out and report back. As you know, I have EL34 boards I could use for my EL84 but proper boards would result in a better solution.

papavienneau
 
Hello Eric,

Nice to see you back :) Did you build the 8 EL34 Baby Huey PCB's ? ;)

Of course the EDCOR CXPP-10-MS-10K (10 watt, 10K) will be perfect for this amplifier, it is very similar to the Hammond 1609 ( Hammond Mfg. - "Classic" Push-Pull - Tube Output Transformers - (1608 - 1620, 1645 & 1650 Series) ) that I am using, see pictures (this one was built with the first version of the PCB !)...

If someone want to order PCB's and share them with others, I would be happy to send him the Gerber files :mail: I am not sure that there will be enough demand for a GB ?

Best regards,
Marc
 

Attachments

  • Photo Baby Huey inside.JPG
    Photo Baby Huey inside.JPG
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  • Photo Baby Huey EL84 detail.JPG
    Photo Baby Huey EL84 detail.JPG
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  • Photo Baby Huey EL84 back.JPG
    Photo Baby Huey EL84 back.JPG
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  • Photo Baby Huey EL84 face.JPG
    Photo Baby Huey EL84 face.JPG
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Hi,

As I was making some improvement on the layout of the EL84 Baby Huey PCB I have seen what Papavienneau tell me in his previous message : I didn't change the reference of the output transformer of the EL34 version :eek: Now it's done !

I have made several other modifications based on my experience in building different Baby Huey :

1) I have switched the location of the 50 VAC bias connector with the decoupling capacitor to reduce the risk of hum due to the proximity of the input signal.
2) I have also increased the size of these two capacitors to accept bigger value without mounting problems.
3) As you have already seen, I have replaced the input pot by a fixed resistor like in the last EL34 Baby Huey.
4) I have added the option to use an external choke instead of the on board resistor to transform the C-R-C filter by a C-L-C filter, There was a demand on the EL34 forum about the possibility to use a choke :)
5) I have modified some tracks to have a better ground plane and shorter connections in several locations...

I hope that now this PCB is better now and that I didn't introduce any fault :checked:, at least the CAD software tell me that there is 0 errors :drink:

Cheers,
Marc
 

Attachments

  • Schema EL84 Baby Huey Rev 1.4.pdf
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  • PCB EL84 Baby Huey Rev 1.4.png
    PCB EL84 Baby Huey Rev 1.4.png
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Hello Marc

As you know, I ordered several EL84 boards for self and friends. We have populated 3 sets of these boards and are in the process of finishing off three amplifiers. One with 6V6 output tubes, one with KT77.s and another with 6550's.

We have tested the 6V6 with 10 watt EDCOR transformers and the other two with one set of EDCOR 60 watt output transformers. A second set of EDCOR 60 watt OT's are on order. These are made to order and take some time to be delivered.

For testing power supply, I had 2 junk toroidals 120/240V to several voltages below 30V. I simply connected both units with one of their 120V windings to 120V domestic supply and their other 120V windings in series to give me 240V for the 6V6 trial. Having no information on these transformers except that they may have been manufactured by Toroidy's pre-owners, I used their heavy guage wire outputs to power up ac-dc regulated supplies for 6V. Then connected a few remaining LV windings in series for biasing. Ugly but functional.

Two of us have ordered power transformers from ANTEK. Mine arrived yesterday.

Had surgery on my right arm last week and am not able to drive, tinker or even type with right hand for 6 weeks. Single finger typing with left hand when right handed is no treat. Soldering is out of the question at the moment.

I took an iPhone video clip of our 6V6 test but do not know how to share.

Time for more right shoulder icing!!

Papavienneau.
 
Hello huggygood,

I have send you a PM...

Cordialement,
Marc

PS: Normally if you buy to Mouser France you don't have to pay custom fees, the VAT is included in your invoice :confused:
normaly yes ,but not the last time I ordered.
they did not have the reference of transitors that I ordered in stock europe and so we brought usa and I ended up with more than 30 € of customs fees for just 5 € of transistors ...
since then, I do not order anything more at mouser.
I contact you this weekend for mosfets
 
If someone want to order PCB's and share them with others, I would be happy to send him the Gerber files :mail: I am not sure that there will be enough demand for a GB ?

Best regards,
Marc
Hi Marc,

Im interested in your El84 PCB. Can i have your gerber Files. i want give a try. by the way what is the max. supply for this el84.?:)
My email: odie1427@gmail.com

Thanks,
odie