You can find it here: EL34 Baby Huey Amplifier
But needs to be checked, because some parts are not 100% correct.
But needs to be checked, because some parts are not 100% correct.
One version of the truth
I think it is fair to say that the two variants of the Baby Huey have diverged somewhat, especially wrt to the power supply and some component tuning.
In order to help keep 'one version of the truth' I have added the latest BOM to the Wiki created by Bas Horneman. It is linked to the 'Group Buy' chapter. It is still attempting to describe both variants, but it is a line in the sand.
BH EL84 Wiki
If there is a neater way to do this, or if there is a style guide for the Wiki, please direct me! (I looked but it was not obvious).
If there is a consensus, and since I have recently built both variants, I can see if I can derive the EL84 version of the BOM.
Going forward I think we should manage 3 tracks, and make more use of the wiki to highlight the combined wisdom of builders:
I think it is fair to say that the two variants of the Baby Huey have diverged somewhat, especially wrt to the power supply and some component tuning.
In order to help keep 'one version of the truth' I have added the latest BOM to the Wiki created by Bas Horneman. It is linked to the 'Group Buy' chapter. It is still attempting to describe both variants, but it is a line in the sand.
BH EL84 Wiki
If there is a neater way to do this, or if there is a style guide for the Wiki, please direct me! (I looked but it was not obvious).
If there is a consensus, and since I have recently built both variants, I can see if I can derive the EL84 version of the BOM.
Going forward I think we should manage 3 tracks, and make more use of the wiki to highlight the combined wisdom of builders:
- Baby Huey EL84 (including on board PSU)
- Baby Huey EL34 (excluding PSU)
- Baby Huey PSU (optimised for BH EL34)
OldHector, excellent thinking and suggestions. I will contribute where I can. It would be helpful to BH builders to have a place (or places depending on what they build) to find information.
One observation - instead of the last I suggest “(optimized for Toroidy TSTA 250/001)”, since that is what Marc did with that PS design.
I also think is should be made clear that PCBs were originally designed and named for EL34, EL84 and TSTA 250/001 PS, but that they are useful and had been used to implement all kinds of relatively high Gm power tubes, PS and output transformer configurations.
Hi Lee,
Congrats with your move into BH territory. The BOM is for one channel/PCB only. You second question had been answered above, but ask if there are further questions.
Good luck!
Thank you! Do I check them against the silkscreen or the schematics? I remember you were saying there were a couple errors in the silkscreen resistor marking.
There are some tips for some values here in my thread:
Slowly building three Baby Huey EL84 - with notes
Then there's R17 substitued with a led, and R16 changed in order to have 2 mA through the leds. I reported the values earlier in this thread.
R6 it's not needed if you install a volume pot.
Slowly building three Baby Huey EL84 - with notes
Then there's R17 substitued with a led, and R16 changed in order to have 2 mA through the leds. I reported the values earlier in this thread.
R6 it's not needed if you install a volume pot.
thank you I appreciate it. Just to be 100% clear there is no dedicated el84 BOM all I have to do is to use one of those el34 from the link you posted earlier and correct it with the parts matching the silkscreen and your notes?
Also, if I want to go CLC what should be the first cap value and the choke L and R? Thank you.
Also, if I want to go CLC what should be the first cap value and the choke L and R? Thank you.
This link takes you to the correct and most recent BOM that covers the EL84 requirements. Since most of the components were the same for the BHEL84 and BHEL34 “Mk1” (EL34 Mk 2 is more different), with few exceptions clearly noted, it made sense to put it in one list.
https://www.diyaudio.com/forums/tubes-valves/326920-el34-baby-huey-amplifier-20.html#post5641739
Since they are on the PCB the capacitors in the CLC filter of the power supply are indicated in the BOM. The inductor is optional and could be from about 1 Henry and up depending on the power transformer you plan to use and the resistance of the inductor. Of course the inductor must accommodate 200ma or more. This requires a bit of design, or trail and error to get the right output voltage. Zintolo decided to do without the L because his simulations confirmed that it may be unnecessary. He plans to go with R27 (10 Ohm, 4 Watt as per BOM) in stead of the optional inductor.
https://www.diyaudio.com/forums/tubes-valves/326920-el34-baby-huey-amplifier-20.html#post5641739
Since they are on the PCB the capacitors in the CLC filter of the power supply are indicated in the BOM. The inductor is optional and could be from about 1 Henry and up depending on the power transformer you plan to use and the resistance of the inductor. Of course the inductor must accommodate 200ma or more. This requires a bit of design, or trail and error to get the right output voltage. Zintolo decided to do without the L because his simulations confirmed that it may be unnecessary. He plans to go with R27 (10 Ohm, 4 Watt as per BOM) in stead of the optional inductor.
With low power and high Raa amplifiers, the current demand is low and a resistor is enough. If you plan to use an inductor, I suggest you to simulate different commercial ones with this software: PSUD2
Do not overdo with Henries, because it will increase the Rdc if you don't increase its current capability, and this will cause too much drop when more current is demanded.
Do not overdo with Henries, because it will increase the Rdc if you don't increase its current capability, and this will cause too much drop when more current is demanded.
Thanks! Thats why I was asking:
Looks like I get the idea and will try to place an order over the weekend. Sadly 10k Toroidy OT transformers Was planing to order from Poland out of stock now :-(
the biggest difference I see is for the film caps: BOM specifies 100nf for C1, C2, but the board indicates 0.22uf, whom should I trust? Also MKT vs MKP and Vishay vs WIMA, I always preferred WIMA mostly for the final look of the board, but can go with Vishay MKT1813, if thats what people think the best.
To add to that, the space there is pretty limited so 0.1uF (100nF) is probably preferred. For the Vishay Axials, I dont think there are any polypropylene caps that fit the space there. I prefer the Axial look (no idea why really) and ordered this part: MKT1813410405.
If there is a WIMA MKP cap that fits there, then that could be your decider.
All that said, my nervosa around coupling caps has been greatly reduced since reading SY's post about it.
SYclotron Audio | Why are people obsessed with coupling caps?
If there is a WIMA MKP cap that fits there, then that could be your decider.
All that said, my nervosa around coupling caps has been greatly reduced since reading SY's post about it.
SYclotron Audio | Why are people obsessed with coupling caps?
No worries, I actually went through the same thing a few months ago assembling a BOM for the EL84 PCB.
I started with the values in the BOM file "BOM EL34 and EL84 Baby Huey Dec 23, 2018.pdf" which is somewhere in this thread.
Then I went through the remarks in Bas's Wiki, and lastly with the comments on an annotated schematic by zintolo also somewhere here.
Here is a link to a Dropbox hosted Google Sheet with the selected components. I didn't build it yet though so can't guarantee the correctness.
I started with the values in the BOM file "BOM EL34 and EL84 Baby Huey Dec 23, 2018.pdf" which is somewhere in this thread.
Then I went through the remarks in Bas's Wiki, and lastly with the comments on an annotated schematic by zintolo also somewhere here.
Here is a link to a Dropbox hosted Google Sheet with the selected components. I didn't build it yet though so can't guarantee the correctness.
Sorry about being unclear. To be clear the 200ma mentioned is a minimum for two channels, i.e. each BHEL84 PCB needs at least a 100 ma, when using EL84 push-pull pairs. A bit more makes one sleep better. At 300V plate to cathode and idling the current draw per EL84 is 40ma; fully driven each conducts 57 ma, the ECC83 draws 2-4 ma, so 100ma average per channel is barely enough.
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