Class D Amplifiers

[captrajesh]

Cap'n - was this the sequence of events for your toroid:

• You ordered a toroid from Miracle, paid for it and were waiting for delivery
• Anurag pointed out that you had budgeted too less for the toroid
• You rechecked and found that you had ordered a 40VA toroid and paid Rs.708 for it instead of ordering a 400VA toroid which costs Rs.3689
• Miracle calls you up to inform you that your toroid is ready and asks for payment again
• You wonder why they executed the order because you had not confirmed the order
• Now, here is the hazy part [for me] - You pay them again?

Hi Keith

Thank you for taking the pain to go through my travails. The sequence of events are as below: -

• I order a toroid from Miracle, pay for it and wait for delivery
• Anurag points out that I had budgeted too less for the toroid.
• I recheck and find that I had ordered a 40VA toroid and paid Rs.708 for it instead of ordering a 400VA toroid, which costs Rs.3689.
• I call up Miracle about the mistake and they ask me to send written request seeking the cost of 400VA Toroid.
• Based on my request, they send me a Proforma Invoice for Rs. 2981 which is the difference amount for the 400VA toroidal (Rs.3689) less Rs. 708 that I have already paid.
• I say, oops thats messing up my budget and say I'll get back but didn't as I could not find any other supplier at the target cost.
• Miracle calls me up to inform that the toroid is ready and asks for balance payment.
• I wonder why they executed the order because I had not confirmed the order.
• I argue with them and they admit their mistake but nevertheless request me to pay them the balance (Rs 2981) and take delivery as the item is already manufactured.
• I can't stretch things too much as my Rs. 708/- is held up with them.
• I say, look it is way beyond my budget and then we hit upon a formula to save some money. (Can't reveal in public)
• I pay up the (reduced) balance amount.

Hope this clears up the haze.

 

[keith_correa]

Hi Keith

Thank you for taking the pain to go through my travails. The sequence of events are as below: -

• I order a toroid from Miracle, pay for it and wait for delivery
• Anurag points out that I had budgeted too less for the toroid.
• I recheck and find that I had ordered a 40VA toroid and paid Rs.708 for it instead of ordering a 400VA toroid, which costs Rs.3689.
• I call up Miracle about the mistake and they ask me to send written request seeking the cost of 400VA Toroid.
• Based on my request, they send me a Proforma Invoice for Rs. 2720 which is the difference amount for the 400VA toroidal (Rs.3689) less Rs. 708 that I have already paid.
• I say, oops thats messing up my budget and say I'll get back but didn't as I could not find any other supplier at the target cost.
• Miracle calls me up to inform that the toroid is ready and asks for balance payment.
• I wonder why they executed the order because I had not confirmed the order.
• I argue with them and they admit their mistake but nevertheless request me to pay them the balance (Rs 2720) and take delivery as the item is already manufactured.
• I can't stretch things too much as my Rs. 708/- is held up with them.
• I say, look it is way beyond my budget and then we hit upon a formula to save some money. (Can't reveal in public)
• I pay up the (reduced) balance amount.

Hope this clears up the haze.

In "audiophool" terms - the veil was lifted. :lol: Thanks!

BUT

Lesson learnt, do not scout for toroidal in India, you end up paying more.

Don't agree with this. Your keyboard is to blame. "Miracle" too. hyeah:

 

[captrajesh]

In "audiophool" terms - the veil was lifted. :lol:

Don't agree with this. Your keyboard is to blame. "Miracle" too. hyeah:

Do you know of anyone else who supplies toroids? How much do you think a 400VA Toroid should / would cost?

Just asking to upgrade my gyan

 

[gobble]

So you did get a 400va toroid but a lesser cost?

Regards

 

[captrajesh]

So you did get a 400va toroid but a lesser cost?

Lesser cost!! I did not understand this thing. How??

The full kit was avaialble from Class D Audio for USD 189 but because of the fiasco, I ended up paying USD 252.54.

If you are saying it cost me less than the rack rate of Miracle, then yes it has. No solace though.:sad:

 

[partymonger]

How are these dvd homeh theatre systems with class d amplifiers?

 

[gobble]

Lesser cost!! I did not understand this thing. How??

The full kit was avaialble from Class D Audio for USD 189 but because of the fiasco, I ended up paying USD 252.54.

If you are saying it cost me less than the rack rate of Miracle, then yes it has. No solace though.:sad:

OK so now you do have a tranny!! Now plug it in and let the music flow through the holes created in your pocket. It will act as a soothing balm

Sorry about your having to exceed your self-imposed limits.

Why do you need a 400VA tranny anyways? How did you compute this figure?

Regards

 

[GeorgeO]

Nothing about Miracle suggested "audiophile". Power transformers are not audiophile-where did you pick up that info? In tube amps output transformers are the ones that need to be high quality.

Miracle is what I have used many times because they do one off pieces, and they are friendly. They also have prior experience making audio application transformers-both power and output.

Rajesh-in case you are unable to get the refund for any reason, check with them if they are willing to transfer the advance that you paid them, to my order. I plan to order a 630VA unit from Miracle after I return for my 5 channel unit using Hypex Class D modules. If this can be done I can pay you the amount.

Edit:
Sorry-I didnt read the full "Audiophool" thread earlier -now I understand better.

George

 

[gobble]

Nothing about Miracle suggested "audiophile". Power transformers are not audiophile-where did you pick up that info? In tube amps output transformers are the ones that need to be high quality.

Miracle is what I have used many times because they do one off pieces, and they are friendly. They also have prior experience making audio application transformers-both power and output.

Rajesh-in case you are unable to get the refund for any reason, check with them if they are willing to transfer the advance that you paid them, to my order. I plan to order a 630VA unit from Miracle after I return for my 5 channel unit using Hypex Class D modules. If this can be done I can pay you the amount.

Hmm maybe I confused output transformers with mains trannies. But I do remember coming across some noise about Fischer or Holden making great "audiophile" trannies for Naim, and some stuff about DC saturation in toroidals and how audiophile mains trannies are given special treatment etc ...

Cheers

 

[captrajesh]

How are these dvd homeh theatre systems with class d amplifiers?

Don't know which ones are you talking about. Some sub-sat systems like logitech Z5500 use class D amps but they cannot be termed audiophile grade.

OK so now you do have a tranny!! Now plug it in and let the music flow through the holes created in your pocket. It will act as a soothing balm

:lol:

Why do you need a 400VA tranny anyways? How did you compute this figure?

Rahul,

The recommended rating of the Transformer is 300VA. A wise electronics guy who happens to be involved in some other project of mine (not audio) said that I should cater for more than the specified rating as we cannot expect any eqpt to perform it's 100% Hope he is right.

Rgds

Rajesh

 

[gobble]

Don't know which ones are you talking about. Some sub-sat systems like logitech Z5500 use class D amps but they cannot be termed audiophile grade.



:lol:



Rahul,

The recommended rating of the Transformer is 300VA. A wise electronics guy who happens to be involved in some other project of mine (not audio) said that I should cater for more than the specified rating as we cannot expect any eqpt to perform it's 100% Hope he is right.

Rgds

Rajesh

The 300VA rating may have been spec'ed keeping in mind some room for overcapacity already. But lets not nit-pik on that. Whats the output rms per channel for your kit btw?

When do you plan to plug it in and hear the sound?

Regards

 

[captrajesh]

The 300VA rating may have been spec'ed keeping in mind some room for overcapacity already. But lets not nit-pik on that.

No nitpicking, thats a good point; I wanted to be safe than sorry. Moreover, as Richie (Grubyhalo) suggested, I intend to upgrade the caps and this might come in handy. This is said to bring about some positive benefits to the SQ (As per the general wisdom of DIYers of Class D audio)

Whats the output rms per channel for your kit btw?

It is 125 Watt RMS @ 8 ohms & 250 @ 4 ohms.

When do you plan to plug it in and hear the sound?

Hmm Actually, I had already connected it to a EI tranny sometime back & really rediscovering my collection. I had posted a short review here: http://www.hifivision.com/amplifiers/8711-class-d-amplifiers-5.html#post144923

AFA toroid is concerned, I will do it the moment I lay my hands on it.

Power transformers are not audiophile

In that case, are there any tangible benefits of using a Toroidal? A cousin of my colleague is in the transformer business and said to be having quite a reputation.

He says that the equipment required to make Toroids are quite different to what he makes his trannies on.

He offered to make an E-I transformer of the same rating with good quality components for a mere Rs. 500/-

What would have been the perceptable differences had that been used?

 

[gobble]

In that case, are there any tangible benefits of using a Toroidal? A cousin of my colleague is in the transformer business and said to be having quite a reputation.

He says that the equipment required to make Toroids are quite different to what he makes his trannies on.

He offered to make an E-I transformer of the same rating with good quality components for a mere Rs. 500/-

What would have been the perceptable differences had that been used?

FYI SoundStage! Max dB - The High-End Mythology of the Toroidal Power Transformer (07/1998)

Cheers

 

[keith_correa]

See >>>>>>here<<<<<<

Oops, gobble beat me to it. Please ignore this.

 

[captrajesh]

What about this Bryston Limited - Music For A Generation

 

[gobble]

What about this Bryston Limited - Music For A Generation

Seen that - That one glosses over things to make toroidals win!! Because Bryston wants to use Toroidals ...

Cheers

 

[keith_correa]

Also with an EI you can make the nasties go away with a flux band mentioned here:

pic linked from sound.westhost.com

Ask your cousins colleague for more options and you should be good to go for Rs.500. Go ahead and do it!

 

[captrajesh]

Also with an EI you can make the nasties go away with a flux band mentioned here

Thanks for the information Keith.:signthankspin:

Ask your cousins colleague for more options and you should be good to go for Rs.500. Go ahead and do it!

Going by the power quality that we have, the issues of DC Offset and Rush Current are what can be described in Bush's terms 'clear & present danger'

I think it worth spending the extra 500 & do a comparision to check out the SQ. If there is no perceptible difference, I might as well go & build a chassis around it than the toroid.

 

[gobble]

Thanks for the information Keith.:signthankspin:



Going by the power quality that we have, the issues of DC Offset and Rush Current are what can be described in Bush's terms 'clear & present danger'

I think it worth spending the extra 500 & do a comparision to check out the SQ. If there is no perceptible difference, I might as well go & build a chassis around it than the toroid.

Make it on a chassis with a female IEC socket get a IEC male - IEC female cable and reuse for all your projects.

Cheers

 

[captrajesh]

Make it on a chassis with a female IEC socket get a IEC male - IEC female cable and reuse for all your projects.

Thanks Rahul, will surely consider that.