Expressions of interest for buying transformers for diy amp ref Linuxguru's thread
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Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa
#$%%%#^&*()(*%$^%$^%^^#%
Delta has no mention of CE/UL certification on their site.
HTH
#$%%%#^&*()(*%$^%$^%^^#%
Delta has no mention of CE/UL certification on their site.
HTH
GeorgeO
Well-Known Member
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa
Miracle Electronics has quoted for both 160 and 320 VA transformers today. Rs1330 for the smaller one and Rs 2335 for the larger, with taxes, levies, and shipping extra, 100% payment against proforma invoice. The lead time is 2 weeks. If anyone wants to place an order, please pm me your email id, I will forward you the quotation, all you need to do is to print it out and place your order directly. I will not be ab;e to follow up with Miracle for individual orders, their contact number and email id is clearly stated on the proforma that they sent me, by and large I have found them to be a satisfactory supplier.
Miracle Electronics has quoted for both 160 and 320 VA transformers today. Rs1330 for the smaller one and Rs 2335 for the larger, with taxes, levies, and shipping extra, 100% payment against proforma invoice. The lead time is 2 weeks. If anyone wants to place an order, please pm me your email id, I will forward you the quotation, all you need to do is to print it out and place your order directly. I will not be ab;e to follow up with Miracle for individual orders, their contact number and email id is clearly stated on the proforma that they sent me, by and large I have found them to be a satisfactory supplier.
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa
I'm planning to visit SV Tronics, Chennai for a quote. What are the complete specs?
Power
Primary - 230 Volts
Secondary - 24-0-24V
Capacity - From 125 to 160 VA for Mono & 250 to 320 VA for Stereo application.
(The exact figure will be within the above VA ratings depending on what is available in stock as custom spec would be costlier)
How about E&I Transformer? It is bound to be significantly cheaper.
I'm planning to visit SV Tronics, Chennai for a quote. What are the complete specs?
Power
Primary - 230 Volts
Secondary - 24-0-24V
Capacity - From 125 to 160 VA for Mono & 250 to 320 VA for Stereo application.
(The exact figure will be within the above VA ratings depending on what is available in stock as custom spec would be costlier)
How about E&I Transformer? It is bound to be significantly cheaper.
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa
The Miracle prices are pretty good, though taxes might be heavy (read: 25%). EI will be significantly less expensive, even at single-unit retail prices - however, EI is bulkier and doesn't lend itself to slim-line cabinets.
Note: The 160 VA unit is usable at 18-0-18 or 22-0-22, i.e. lower rail voltages. The max. audio output power will be lower, but this may not be an issue for a compact bookshelf or HT setup.
The Miracle prices are pretty good, though taxes might be heavy (read: 25%). EI will be significantly less expensive, even at single-unit retail prices - however, EI is bulkier and doesn't lend itself to slim-line cabinets.
Note: The 160 VA unit is usable at 18-0-18 or 22-0-22, i.e. lower rail voltages. The max. audio output power will be lower, but this may not be an issue for a compact bookshelf or HT setup.
stereorules
Active Member
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa
The size of the enclosure being discussed was ~2.5 U or 3 U ..Is that not enough to fit the EI one ? What about the SQ difference between the EI and the toroidal ?
On a side note, what would be the approx shipping costs for these transformers since they are heavy ?
The size of the enclosure being discussed was ~2.5 U or 3 U ..Is that not enough to fit the EI one ? What about the SQ difference between the EI and the toroidal ?
On a side note, what would be the approx shipping costs for these transformers since they are heavy ?
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa
The SHAM-brand 240VA EI will fit in 2.5U. SQ will be comparable - the main issue with EI is the leaked 50 Hz EMI, but hum pickup is not really an issue with the MyRef, so EI is usable. No idea about shipping costs - it's probably best to buy locally if you can.
The SHAM-brand 240VA EI will fit in 2.5U. SQ will be comparable - the main issue with EI is the leaked 50 Hz EMI, but hum pickup is not really an issue with the MyRef, so EI is usable. No idea about shipping costs - it's probably best to buy locally if you can.
stereorules
Active Member
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa
I assume this would reduce the output by a few watts ? Any idea what the next higher one would be ? Sorry, but am completely new to this ...Thats why these questions may seem stupid to you ..Pl bear with me ..
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa
200 to 240VA is perfectly adequate for two monoblocks, i.e. a stereo setup. The output is about 80W max at about 60% efficiency, so even a 160VA will be sufficient, even taking into account rectifier losses and auxiliaries (10 watts max.).
The 160VA toroidal will work for the lower-power setups, and anything over 200VA will be sufficient for the full power setups. 300VA is overkill, but gives some peak-power margin to avoid voltage sags/clipping on heavy bass passages.
The best premium option is the Miracle 300/320VA.
200 to 240VA is perfectly adequate for two monoblocks, i.e. a stereo setup. The output is about 80W max at about 60% efficiency, so even a 160VA will be sufficient, even taking into account rectifier losses and auxiliaries (10 watts max.).
The 160VA toroidal will work for the lower-power setups, and anything over 200VA will be sufficient for the full power setups. 300VA is overkill, but gives some peak-power margin to avoid voltage sags/clipping on heavy bass passages.
The best premium option is the Miracle 300/320VA.
GeorgeO
Well-Known Member
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa
Re Miracle's quote VAT is 13.5%, Excise Duty is 10.3% plus shipping will be at actuals, so, yes , it will add up-but this is applicable to all vendors, I think.
Re Miracle's quote VAT is 13.5%, Excise Duty is 10.3% plus shipping will be at actuals, so, yes , it will add up-but this is applicable to all vendors, I think.
stereorules
Active Member
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa
Thanks for clarifying so clearly ...
Thanks for clarifying so clearly ...
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa
Will not a good bank of charging capacitors in PSU overcome this and supply the required peak power as needed, with a lower rated Trafo?
Will not a good bank of charging capacitors in PSU overcome this and supply the required peak power as needed, with a lower rated Trafo?
goldyrathore
Active Member
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa
The rates are very good indeed. Rate for 320VA is lower than what I had received from Miracle a couple of months back. Are these rates for small orders or quite a few numbers?
Miracle quotes taxes of abt 25% which is on the higher side. AFAIK others generally quote 14% .
IMHO we should consolidate the number of orders and then ask for re-quote with applicable discounts, if any. Generally B2B suppliers quote a higher price for small quantities.
The rates are very good indeed. Rate for 320VA is lower than what I had received from Miracle a couple of months back. Are these rates for small orders or quite a few numbers?
Miracle quotes taxes of abt 25% which is on the higher side. AFAIK others generally quote 14% .
IMHO we should consolidate the number of orders and then ask for re-quote with applicable discounts, if any. Generally B2B suppliers quote a higher price for small quantities.
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa
George, the SV Tronics guy is significantly cheaper. He had given me a quote for my class D Trafo for Rs. 2100/- all inclusive whereas Miracle had given me a quote for 3850/-
I assume this would be the case if it is mounted vertically. I have a 400VA 35-0-35 V Trafo which I'm using for my Class D Amp. If mounted horizantally, can even fit into 1U casing.
What would be the optimum voltage at secondary? Is it 18 or 22 or 24 or even higher?
So I assume that any trafo available off the shelf (and not custom made for minimising costs) should be sufficient I guess.
If 300VA itself is overkill, why go for 320 and increase the weight and cost unnecessarily?
George, the SV Tronics guy is significantly cheaper. He had given me a quote for my class D Trafo for Rs. 2100/- all inclusive whereas Miracle had given me a quote for 3850/-
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa
Is this a toroidal or EI? Their website also lists R-Core. Can you call your contact (not the sales manager) and ask about it on my behalf? I had no luck reaching a sensible person to talk to ...
Thanks
George, the SV Tronics guy is significantly cheaper. He had given me a quote for my class D Trafo for Rs. 2100/- all inclusive whereas Miracle had given me a quote for 3850/-
Is this a toroidal or EI? Their website also lists R-Core. Can you call your contact (not the sales manager) and ask about it on my behalf? I had no luck reaching a sensible person to talk to ...
Thanks
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa
Valid point. Over to Shiva for expert opinion.
Valid point. Over to Shiva for expert opinion.
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa
Hi Rahul,
That was for a toroid. EI will be far more cheaper. I got my 400VA Trafo for Rs. 500/- (Of course without band pass) I'm thinking of going for EI to keep costs down.
Rgds
Rajesh
Hi Rahul,
That was for a toroid. EI will be far more cheaper. I got my 400VA Trafo for Rs. 500/- (Of course without band pass) I'm thinking of going for EI to keep costs down.
Rgds
Rajesh
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa
Yes, up to a point - there is space on the Version 1.3 PCB for only a pair of 35mm caps, one for each rail. The maximum feasible value of each of these is 22,000uF/50V, available in Panasonic TS-UP, which is a general-purpose cap, but acceptable for audio. The higher-quality caps are bulkier, so you'll have to settle for a lower value - for instance, the blue Yamaha/Nippon-Chemicon 12,000uF/71V.
On the Version 1.2 Twisted Pear board, the space is even tighter - only 30mm diameter capacitors. This limits the value to about 10,000uF/50V in practice, and there are very few premium capacitors that will even fit - you'll be lucky to find a 4700uF premium capacitor that will fit.
Yes, up to a point - there is space on the Version 1.3 PCB for only a pair of 35mm caps, one for each rail. The maximum feasible value of each of these is 22,000uF/50V, available in Panasonic TS-UP, which is a general-purpose cap, but acceptable for audio. The higher-quality caps are bulkier, so you'll have to settle for a lower value - for instance, the blue Yamaha/Nippon-Chemicon 12,000uF/71V.
On the Version 1.2 Twisted Pear board, the space is even tighter - only 30mm diameter capacitors. This limits the value to about 10,000uF/50V in practice, and there are very few premium capacitors that will even fit - you'll be lucky to find a 4700uF premium capacitor that will fit.
Re: Expressions of interest for buying transformers for diy amp ref Linuxguru's threa
24-0-24 is Mauro's recommended secondary voltage, and can be considered to be the best balance between sonics and power. There is some anecdotal evidence that lower voltages like 22-0-22, 20-0-20 or 18-0-18 are better for sonics on the MyRef, but I haven't tried them. Lower voltage secondaries will constrain the audio output power, naturally.
320VA is mentioned, because that's what Miracle has quoted for - it's slightly higher powered than the 300VA standard products on their website.
What would be the optimum voltage at secondary? Is it 18 or 22 or 24 or even higher?
If 300VA itself is overkill, why go for 320 and increase the weight and cost unnecessarily?
24-0-24 is Mauro's recommended secondary voltage, and can be considered to be the best balance between sonics and power. There is some anecdotal evidence that lower voltages like 22-0-22, 20-0-20 or 18-0-18 are better for sonics on the MyRef, but I haven't tried them. Lower voltage secondaries will constrain the audio output power, naturally.
320VA is mentioned, because that's what Miracle has quoted for - it's slightly higher powered than the 300VA standard products on their website.
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