Expressions of interest for buying transformers for diy amp ref Linuxguru's thread

Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa

Hello George and All

I would like to add my interest to procure a couple of these toroidals too...
Do let me know the payment methods...

Thanks.
venu
 
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa

OK Guys,

So Shiva, shall we finalise the trafo?

24-0-24 Volts @ Secondary or is it dual

200 VA

Is it 4 amps or 5 amps?

Do finalise the specs and post it so that I can place the order for the prototype
 
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa

captrajesh said:
OK Guys,

So Shiva, shall we finalise the trafo?

24-0-24 Volts @ Secondary or is it dual

200 VA

Is it 4 amps or 5 amps?
Click to expand...

I think that 24-0-24, 200 VA will suit the needs of most people for the MyRef as well as other discrete designs that require approx. +/- 32V rails. It works out to a little more than 4 Amps, which should be fine. You may want to check if there is a preference for 240 VA, which gives some additional engineering margin, on this forum. I'm fine with 200 VA.
 
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa

I think it's worth going fora 240VA option for those who prefer to go for a little cushion than be on the bordeline. The cost will only be very marginally more.
 
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa

linuxguru said:
I think that 24-0-24, 200 VA will suit the needs of most people for the MyRef as well as other discrete designs that require approx. +/- 32V rails. It works out to a little more than 4 Amps, which should be fine. You may want to check if there is a preference for 240 VA, which gives some additional engineering margin, on this forum. I'm fine with 200 VA.
Click to expand...

GeorgeO said:
I think it's worth going fora 240VA option for those who prefer to go for a little cushion than be on the bordeline. The cost will only be very marginally more.
Click to expand...

Actually, the amp that was played at my home the other day had only 100 VA and it sounded quite good to me. The 160 VA Trafo in itself is 60% bigger.

When we were discussing the issue the other day, Shiva reckoned that 160 VA is more than enough but we opted for 200 VA (25% extra headroom) for additional engineering margin considering that the price difference is very minor (Rs 150 extra)

Now, this would become 50% extra headroom.


So what should we finally settle for?
 
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa

I'm assuming that we are talking about a single 200 or 240 VA trafo for a stereo amp ( 2 mono blocks) and not two trafos right ?
 
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa

SVTronics 24-0-24, 240 VA - Rs.1400
Click to expand...

What was the quote from Miracle again?

I would rather go for a UL and CE certified one for what its worth... :cool:

Cheers
 
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa

I dont think miracle tfr are ul listed, but it is UL recognized(u and inverted R instead of UL) meaning, the transformer as such is not tested by UL,but built using components that are recognised by UL

CE is a manufacturer "self certification" that it complies to EU standards and can be sold in EU so i wont put too much weight into that
 
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa

OK guys,

I'm placing the order for 200 VA Transformer.
 
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa

The different types are monoblock-separate but identical amps for each channel, including enclosures, Vs "dual mono"-two trannies but using a common board after the power supply and a single enclosure Vs stereo-a single tranny and a single enclosure


>I'm assuming that we are talking about a single 200 or 240 VA trafo for a stereo amp ( 2 mono blocks) and not two trafos right ?
 
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa

The cheapest would be two boards with single trafo in single chassis for stereo application. I'm planning to build exactly this and the 200 VA Trafo is sufficient for this.
 
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa

linuxguru said:
+/- 28V rails are about the best for sonics with a traditional LM3886 gainclone. The MyRef is however a different topology, so it's hard to say without extensive auditioning, but it's reasonable to say that +/- 28V may also be optimal for sonics here. That would imply a 22-0-22 secondary.
Click to expand...

By the way, if sonics is greater, is it not worth while to go for 22-0-22 rather than 24-0-24? Also, I'm also seriously thinking of going in for EI instead of Toroid. Wot say guys?
 
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Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa

captrajesh said:
By the way, if sonics is greater, is it not worth while to go for 22-0-22 rather than 24-0-24? Also, I'm also seriously thinking of going in for EI instead of Toroid. Wot say guys?
Click to expand...

I haven't actually tested 22-0-22 so far, only 24-0-24. It shouldn't make a huge difference to sonics, at any rate - so I'd suggest staying with 24-0-24, 4 or 5A (192/200 or 240 VA), which is a more useful rating for a whole bunch of other gainclone and discrete designs, apart from being a very standard voltage.

EI vs. Toroid: It's each DIYers decision, but at S V Tronicks prices, I'd suggest going with a toroid - the price multiplier with respect to EI is only about 2 to 2.5x, and it's more compact.
 
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa

linuxguru said:
EI vs. Toroid: It's each DIYers decision, but at S V Tronicks prices, I'd suggest going with a toroid - the price multiplier with respect to EI is only about 2 to 2.5x, and it's more compact.
Click to expand...
One of our fellow members from here in Hyd had a doubt regarding the qlty of the trafo that SV makes...He is of the opinion that the actual VA rating of the SV trafo maybe less than what they are quoting ..
 
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa

stereorules said:
... a doubt regarding the qlty of the trafo that SV makes...He is of the opinion that the actual VA rating of the SV trafo maybe less than what they are quoting ..
Click to expand...

The sample 200VA transformer that was shown seemed to be of adequate weight and dimensions, but unless a teardown is performed to determine the actual gauge of wire and core cross-sectional area, there's no easy way to tell.

That's one of the reasons why an initial prototype will be ordered and tested, before confirming larger quantities.
 
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa

linuxguru said:
The sample 200VA transformer that was shown seemed to be of adequate weight and dimensions, but unless a teardown is performed to determine the actual gauge of wire and core cross-sectional area, there's no easy way to tell.

That's one of the reasons why an initial prototype will be ordered and tested, before confirming larger quantities.
Click to expand...

This is my first post on this forum.
200 VA transformer should be made in lamination number 16 (or 4 ) and stack size of 2" ( 50mm). If you want the height of transformer to be low get it made in core no. 3 stack size 3" (75mm).
regards
J. P. Singh
 
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