Iron Pre Essentials Kits For The DIYA Store - Register Your Interest

[nicoch58]

What can be improve
little more spacer for 12.5mm C12>C19 , btw just a little diy....
Trade one In for a second Out 😉

 

[nicoch58]

This is a partial BOM that can be import on mouser ,just rename pdf in xlsx
you still need heatsink ,led ,rotary sw,jumper /Headers ,transformer

 

[Zen Mod]

little more spacer for 12.5mm C12>C19 , btw just a little diy...

that's deliberate, to prevent audiophoolery

 

[nicoch58]

hat's deliberate, to prevent audiophoolery

I will drill the pcb 🤣

 

[Zen Mod]

10mF/100V, preferred value

 

[Vunce]

….with screw terminals.

 

[nicoch58]

Boyz simple UKZ

 

[Zen Mod]

wanna teaser(s)?

 

[Minarai]

So, I've bought more Fujitsu Takamisawa RY-24W-K relays and CK1060 rotary switches because I ended up with only 2 relays for myself after helping others get what they needed for their projects🤣. This time, to keep it from getting wonky, I will offer 5 relays and a switch for $20 or 6 relays and a switch for $22.50 with USPS First Class shipping (thats about $14 less than buying them from two vendors and paying shipping separately). I will make a post in the 'for sale' section so that any further discussion won't clutter this thread, but please message me if you would like to reserve a set of parts for your iron pre build.

 

[ranshdow]

😏

Tempted to try powering the Emerald phono stage off the Iron Pre shunt reg rather than with it's own trafo, as designed. The trafo is only 18V, 25VAC.

Thanks to @Gianluca for drilling the bottom panel like I wanted. The holes are perfect. 👌

 

[Zen Mod]

you can do that, cheapskate



what's current consumption of Emerald, maybe you need to alter programmed current for that rail?

 

[ranshdow]

The Emerald is dual rail and while I don't know it's current draw, the Emerald's design has it's own onboard regulator and calls for it's own 25VAC to 35VAC trafo. Per the second hole in the baseplate 😉

 

[Zen Mod]

what's dual rail and you're speaking about one secondary voltage?

give it separate xformer, to avoid headache

 

[ranshdow]

Ah, yes, typo in #1330. +/- 18V. Not only second trafo, now thinking I need fancy cans for them both. The one shown was only $20 & shipping amortized over some other stuff, anyway.

 

[Zen Mod]

if VA of your xformer for Iron Pre is allowing, connect Emerald to it too

do your math

if you're unsure ( as I am in things I know squat about), give me current number for Emerald and VA for Donut you already put in

damn, you have entire corner empty there, you should move that Donut all the way to front plate and left, if you already can

 

[ranshdow]

Thank you for your help, ZM.

The input power for the Emerald boards is for rectified 2 x 12VAC per the diagram below. I couldn't find a current draw spec from either the literature that came with it or in RJM's thread on same here, last I looked for it a few weeks back. But the input to the Emerald shunt reg is shown as +/- 18V rectified, unfiltered and unsmoothed DC. Hence I thought if it didn't draw too much current (vague and imprecise I know), maybe the Emerald could draw very smoothed +/- 18V DC from the Iron Pre's shunt reg, into it's own shunt reg.

The trafo I have in hand today is a Triad Magnetics VPT36-690: 115VAC to 2 x 18VAC, 25VA. I spec'd it to power the Iron Pre on it's own, not both the Iron Pre and the Emerald. I'm fine to do this with two trafos, but, there'd likely be less magnetic interference with one trafo up in the front corner, as you noted.

 

[Zen Mod]

shunt regs
programmed per rail as 0V65/22R1=1pprox. 30mA

means roughly taking 1,1W from 36Vct xformer

per channel, as I see it, so 2.2W

you're good taking juice from saidf xformer to both Iron Pre and Emerald


Iron Pre is having regs programmed for 0V65/(15R//18R)=80mA


so, stereo Iron Pre sucking under 3W

 

[Skylar88]

Iron Pre is having regs programmed for 0V65/(15R//18R)=80mA


so, stereo Iron Pre sucking under 3W

Sorry about the rookie question. Why then specify a 20VA transformer if less than 3W is needed? That points to a very low power factor.

 

[Zen Mod]

That points to a very low power factor.

well, not exactly; think what's Iq of small (or any) Donut; it is not A Class amp, sucking it all from the mains, all the time



look around

for some other projects (of same basic power consumption), you'll need to use 50 or 100VA



fact is - I'm used on getting custom made Donuts, and guys producing them sez that makin smaller than 10VA is major PITA - everything is fragile and result is that smaller ones than 10VA needs to be more costly than 10VA
same logic - they prefer making 20VA than 10VA, speaking of ease of manufacturing

that being that

main reason is - I prefer cold Donuts

second main reason - "stabilization factor" is much better as you go up with VA of Donut

" " is difference in voltage between loaded and unloaded xformer; if you ever measured small xformer unloaded, you'll probably cry here, asking for explanation what's wrong with your measurements

 

[Skylar88]

Oh, ok. That makes a lot of sense. I can imagine small xformers are like small electric motors with which I'm very familiar. Efficiency is usually not good. Iron loss (eddy currents) and copper loss in the windings are the culprits.

I wasn't complaining, btw. I noticed that small toroidal xformers are not cheap.