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Old 23rd February 2011, 06:33 PM   #41
qusp is offline qusp  Australia
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excellent!! go team
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Old 28th February 2011, 03:31 PM   #42
EUVL is offline EUVL  Europe
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A piece of bad news today, unfortunately.

Both team members for PCB layout are temporary out of action, due to computer problems and unexpected events.
Though they both emailed to say they would try to catch up, I have asked them to take their time to get things properly settled first.

There are more important things in life than this hobby.
For the delay, I beg for your understanding.


Patrick

.

Last edited by EUVL; 28th February 2011 at 03:45 PM.
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Old 28th February 2011, 03:56 PM   #43
qusp is offline qusp  Australia
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Quote:
Originally Posted by EUVL View Post
A piece of bad news today, unfortunately.

Both team members for PCB layout are temporary out of action, due to computer problems and unexpected events.
Though they both emailed to say they would try to catch up, I have asked them to take their time to get things properly settled first.

There are more important things in life than this hobby.
For the delay, I beg for your understanding.


Patrick

.

there are indeed, we've waited this long, whats another short while. no sense rushing and risking further problems, or risking your health working too hard. all the same of course i hope things sort themselves out soon, but not at the expense of the developers
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Old 2nd March 2011, 12:40 AM   #44
alazira is offline alazira  United States
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Default transformer

Quote:
Originally Posted by qusp View Post
well i have received no reply from fitzfish on the transformer query. perhaps he will see here. perhaps i am not worthy? anyone else in the build team i can contact who might know?

perhaps the switch to fets also was congruent with his advertising byline creating 'all fet' designs hehe
Hi qusp,
I too have not heard from fitzfish. I sent an inquiry to SumR with EUVL's recommended specs and received the following reply:

Quote:
A/ Re 500VA toroid

- your max dimensions 150 x 75 allow for a larger core, which allows for
winding heavier wire.
- However, to wind heavy wire bifilar becomes a difficulty, both in size of
machine and amount of stress one has to put on the core when winding.
- we can wind, on this larger core, the heavy awg wire, but only single
file.
- You have asked for everything to be Class B 130C. All transformer parts
used in assembly meet 130C, except the stranded leads 105C which are in
stock.
Please let us know if you require teflon or other higher temperature
leads as this adds to cost.
- The secondaries can be solid wire, with sleeving, again all sleeving in
stock is UL listed Class A 105C.
I was wondering what transformer you (and others) were ordering.
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Old 2nd March 2011, 01:07 AM   #45
qusp is offline qusp  Australia
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yeah i got the same reply this morning, except one of us ordered a 600va version, seems 500va is the limit. but havent thought about the email yet, only just woke up. we need some input here from patrick, or someone who knows, because we were given rather specific instructions for the order by Patrick, so i'm not sure whether the limitations and lack of biflar is a deal killer.
also i gave him the model number generated by the enquiries, i wasnt expecting to get questions back since he made the number

Last edited by qusp; 2nd March 2011 at 01:09 AM.
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Old 2nd March 2011, 01:12 AM   #46
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Quote:
Originally Posted by pchw View Post
Here is what the invoice said:
RC0600 915 5 banded transformer
My invoice number is 5149.

Hope this will help.
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Old 2nd March 2011, 01:14 AM   #47
qusp is offline qusp  Australia
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i already sent him that with the request, so tbh i'm a little confused with receiving this email beck, i was just expecting an invoice or estimate for completion
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Old 2nd March 2011, 04:49 AM   #48
EUVL is offline EUVL  Europe
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The transformer Mark Lai ordered has not yet arrived, so I cannot give you many more details.

Fitzfish will be out of action for a while for reasons I promised not to disclose. Please try to understand.
As I said, there are thing in life much more important than this hobby.

I can give you my opinion to those questions.
But since we already ordered once, I don't want to add to the confusion.

Please be patient for a few weeks.


Thx,
Patrick
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Old 2nd March 2011, 08:35 AM   #49
alazira is offline alazira  United States
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Quote:
Originally Posted by EUVL View Post
The transformer Mark Lai ordered has not yet arrived, so I cannot give you many more details.

Fitzfish will be out of action for a while for reasons I promised not to disclose. Please try to understand.
As I said, there are thing in life much more important than this hobby.

I can give you my opinion to those questions.
But since we already ordered once, I don't want to add to the confusion.

Please be patient for a few weeks.


Thx,
Patrick
No doubt that real life takes priority. I wasn't complaining about Fitzfish. I wish him well.
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Old 2nd March 2011, 09:29 AM   #50
EUVL is offline EUVL  Europe
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While trying to give fitzfish more time, I shall post a few comments to SumR’s reply :

a) There is no need to use up the maximum volume completely. A 500VA core already has quite some reserve. If one were to go for a 600VA core (as we did in the GB), it is only for the reason that the core will have even more margin from magnetic saturation, and hence should be quieter. The winding is still 500VA. It is not necessary to go to a heavier winding.

b) Bifilar winding means that the 2 secondaries are wound side-by-side. This means that they see the same magnetic fields, and hence gives the same output voltage. The inter-winding capacitance also increases, and this has been used advantageously e.g. by Plitron in their NBT transformers :

6moons audio reviews: BPT BP-3.5 Signature

But it is not must have. If SumR feels happier without bifilar for whatever reasons, then so be it.

c) The specification I wrote was based on a transformer with enamel wires (where Class B insulation is standard and also required inside the transformer) as output leads, and not stranded wires. Various other people wanted stranded leads for the GB, so that’s why it came with stranded leads. There is no need to specify 130C insulation for the output leads, so Class A is good enough. There is no need to go teflon.


As always, the above only represent my personal opinion. I am no expert in transformer design, and we have not tested the SumR toroidals as yet. If you do not want ot wait for your results and want to go ahead now, for whatever reason, I suggest that you should at least inform yourselves by looking into issues like bifilar winding, insulation classes, etc. before making any decision.

On top of that, you can always open a new thread just for power transformers, and ask Nelson of his opinion. It is his daily bread & butter, as opposed to just a hobby for me.


Patrick
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