• 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.

Oh no...not another Baby Huey EL84 build.

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#141
Hi Bas,
Don’t mean to stalk you

Can you give the measurements of your case please including height, depth , width in metric cm or mm?

Could you also say what size holes you had to drill for the valves / tubes?

Anything else that would be good to know it is relevant would be appreciated?

It will help me thinking about either building or sourcing a case?

What type of top plate have you used? Steel, aluminium etc

Thanks again

Lee
 
#142
Topplate aluminium.

Width 35cm*30cm*11cm (But as usual I would have preferred a bigger cabinet. I was quite nervous about the proximity of the power transformer to the output transformers.) So go bigger if you can.

I drilled them bigger after I found out the alignment was not exact...and I could not fit them. Unfortunately I did determine the holes when the pcb was still unsoldered too. Think the holes were 28mm. But that is trivial. Just don't drill them much bigger so that a kid can't stick his fingers in.

A relevant tip is that when your pcb is still unsoldered to...to determine where to drill the holes.
 
#145
Bas Horneman said:
You are welcome.

Just a correction.

Should be when I had already soldered the board.
Click to expand...

Sorry, Bas, your “correction” confused me a bit. I thought you wanted to suggest that one should mark the top plate holes, using the PCB, before soldering parts to the PCBs. Is that correct?

I am also curious if you have tweeked R13 yet. I believe you installed 33k and were going to listen how it performs as you lower that resistance by adding parallel resistance to R16.
 
#146
Sorry, Bas, your “correction” confused me a bit. I thought you wanted to suggest that one should mark the top plate holes, using the PCB, before soldering parts to the PCBs. Is that correct?
Click to expand...
Yes. That is correct!

I am also curious if you have tweeked R13 yet. I believe you installed 33k and were going to listen how it performs as you lower that resistance by adding parallel resistance to R16.
Click to expand...
No. I was lazy. And added another 33k. So now the value is 16.5k. I'm just going to leave it there and not tweak it...
 
#147
Hi Baz,

I am thinking I will end up with the Toroidy PSU and OPTs

If I were to use a choke would this one from Toroidy be suitable 10H 500ma

77a7c5f9cac2ec628fa810e3ebaae161.jpg


TDS10/500 - Toroidal Choke 10H 500mA DC - Shop Toroidy.pl

Technical data
Core type toroidal
Inductance L 10H
DC Resistance 66,5Ω
Nominal DC Current 500mA
Nominal voltage 400V
Dimensions 88 mm (OD) x 61 mm (h), weight: 1,9 kg
Dimensions SUPREME 129 mm (OD) x 80 mm (h), weight: 3,6 kg

Thanks again

Lee
 
#148
eldarvanyar said:
Hi Baz,

I am thinking I will end up with the Toroidy PSU and OPTs

If I were to use a choke would this one from Toroidy be suitable 10H 500ma
Click to expand...

That would be overkill. Marc specified a much smaller choke, I forgot the exact specs, but it was something like 1.5H at 200 ma. (Have you checked the “real Baby Huey EL84” thread? Long but lots of good stuff).

No harm in using the 10H 500 ma choke, but it is just more than needed. For a Baby Huey EL84 stereo amp you will need around 200ma and based on Toroidy’s offerings I would go for: TDS10/250 - Toroidal Choke 10H 250mA, since their smallest (6H) is only a few Zloties less. However, if you plan to rebuild a EL34/KT88 later on, perhaps an investment in the 500 ma current capable choke could be justifiable.
 
#150
Hi Bas I have ordered two BH EL84 boards from Prasi and one psu board. I have been wondering about ordering another psu board. It’s going to take a long time to get here due to COVID-19.

I would like to take advantage of using the 6N2P -EV and 6P14P-EV as well as
12ax7 and EL84 configurations by installing toggle switches if that is viable.

I already have an EL34PP and and a KT88 amp which is why I am keen on building the BH EL84 amp.

The choke I enquired about came up automatically on the Toroidy website when I was looking at the EL84 PP OTs.

The Dutch guy never replied - I sent two emails one in Englishman one with google translate. I have been reading up on EI Transformers, C Core Transformers and The C transformers looked really good. I

I have been ready through the Long BH EL84 thread but it seems that there have been different versions along the way and it’s all getting a bit confusing.

I think if there was a main DIY build thread that just showed the process similar to Spaceistheplace has done for the EAR 834P Phono Clone it would really help novices like myself.

https://www.lencoheaven.net/forum/index.php?topic=26658.0

Thanks again

Lee
 
#153
Thanks Bas

So just to confirm as we have 3 chokes mentioned

The 10h 500ma is overkill and not needed

That leaves

The TDS 10/250 10h 250ma

The TDS 12/200 12h 200ma

Which one is the best to go for and why?

Thank you again for your time and patience.

Lee
 
#154
Hi Lee,

If you use the psu board. Get the one big choke.

If you are using the boards only. Use Either of the two. You won't be able to tell the difference between 10 or 12. If all it took was to get the biggest capacitance or largest inductance it would be easy. But look at a psu as a stream. The more pebbles in the stream the more swirls, eddies and turbulence you get. Do things as simple as possible but you have to do enough.

So I would suggest to use the psu board. And then just use the on big boatanchor choke. 😀.

Then on the board you could use a resistor where the chokes are supposed to go...to tweak your voltage.
 
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