New API 525 build thread.

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yep you're right, the same.  Back to my original comment; I was looking at Peter's schematic, which ain't right. 
 
Does anyone know if Ed made a run of transformers for this new version of the 525? He said he had done enough transformers for the ones that bought the v1 of the Peter board.

Where can I get trafos in the UK? I know Jeff @ classic API sells them but was trying to avoid postal charges and the likes :)

J
 
jplebre said:
Does anyone know if Ed made a run of transformers for this new version of the 525? He said he had done enough transformers for the ones that bought the v1 of the Peter board.

Where can I get trafos in the UK? I know Jeff @ classic API sells them but was trying to avoid postal charges and the likes :)

J

If you check the mainboard BOM, on first page, it says you can use 2X SOWTER 9935, don't know if that will be cheaper than Jeff at the end?


T.
 
Yeah, last case scenario I was considering that.
But when I spoke with Peter he said "use Ed's have no idea what he has"

.... You know, the ever helpful Peter :)
 
Question about the input trafo. The original has no input trafo, am I correct?
For the people that did go for the input trafo, is there really a benefit? I mean the unit is coloured enough (at least the original ones) is it worth to fork out those £40 on a Lundhall?

Pardon my noobiness if the original has in fact a trafo input. (never actually opened one, but the pictures I've seen only had the o/p and sidechain trafo)
 
The original has two transformers, but one is the output transformer and the other is used to generate the voltage that goes to the FET. No input transformer.

I built mine with the line receiver as proposed by Peter. Works fine for me.
 
901 said:
The original has two transformers, but one is the output transformer and the other is used to generate the voltage that goes to the FET. No input transformer.

I built mine with the line receiver as proposed by Peter. Works fine for me.

Thank you 901. As expected, I guess.
 
jplebre said:
Does anyone know if Ed made a run of transformers for this new version of the 525? He said he had done enough transformers for the ones that bought the v1 of the Peter board.

Where can I get trafos in the UK? I know Jeff @ classic API sells them but was trying to avoid postal charges and the likes :)

J

in the end, getting Ed's transformers from Jeff in the US was still cheaper for than the sowters (UK folks). ;)
Grayhill 71BDF30-02-1-AJS in stock at RS 2508966576
 
any HFE requirements? I have tons of under 400-450hFE BC184 :p
I guess I could also use the BC550. I saw on another post they should be matched, not a problem there (Q1 and Q2)

 
are 1/8w ok for the miniature resistors? I've used ohms law for worse case scenario (+16v to ground) and it did give 0.250w
But I don't think in both cases it's "signal" to ground so that shouldn't matter.

I wanted to avoid carbon and the only ones I found were either 1/8w or carbon.

What are you guys getting?

Cheeeeeers
 
Hey guys

What exactly is CG and RG?
Since it has a weird naming convention decided to look up but couldn't find on original schemo.

Is this a remnant from the old build?

Is this optional, or necessary for either the A4 or Lundahl?

I'm going A4 so I skiped XR1 and XR2. but I'm confused with CG/RG
 
will 2k make a difference for R75 (2.2k?) having a hard time finding the right ones for the right footprint.

is it just setting impedance for the rail supply?
 
Big Pete :)

in the first page of the thread you posted a pic with PRV6 lin as i/o? was this only for the picture or>

 
2Q

is it normal that the sidechain opamp (a3) big trannies run slightly hotter than the rest? (eg. almost too hot to the touch?)
and:

Anyone else see the meters going full on when engaging true bypass?


EDIT: did the same mistake as 901 with the sidechain trafo I'll try and fix it later but that should be the end of it.. nothing to see here move along
 
in normal conditions also does it? or just because i have the trafo mounted wrong?
 
Yes, bypass lights the whole meter.

Odd! I thought that the switch was simply a 4pdt. 2 poles for the + and - copy of the signal or the trafo out, and then the extra pole used for the bi-colour LED.

Signal should still go through the whole circuit. O/p trafo still sees the 600ohm load is still there, nothing else changes in the circuit so why does this happen?

I feel like some probing and trace cutting coming on just need to understand what else is being affected :p

(not having a go in anyway, just want to learn more :)
 
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