Where to source a transformer? EI or toiroid?

[sdk]

Hi,

My DIY project is progressing slowly.

I've been trying to find a supplier for the transformer who will make the windings I want.

Any FMs who have experience in sourcing one and can share contact details in Mumbai as well as costs?

While on the topic, what type of core is preferable? EI or toroidal?

What specs or tolerance should I be specifying?

What tests to conduct on taking delivery?

Regards

 

[sdk]

Thanks, will give them a try

Anyv reliable local Mumbai leads, anyone?

 

[magma]

If .you know the specs
A mail
To
torotrans in Pune
Or
Electro magnetic devices banglore

Should get you a reply

Both are good manufacturers and supply correctly rated transformers

Google the above names
You will arrive on their website

For smaller supplies like preamps an
Rcore is good

Fir larger supplies like powe amps a torroid is good

The designer whose power board you buy will be a better judge of which kind of transformer you should buy

 

[magma]

Mumbai has a couple of old school guys
Who are decent but expensive
Due to higher rentals and expenses in mumbai

Others are hand winders working off shacks in Andheri or lamington road

Torotrans or electromagnetic devices
Would be a safer more profesional bet

 

[sdk]

Excellent replies

Thank you all

On a side note, my friend insists that all boards that need DC voltage should always get 5V AC current more than DC

So for the preamp that rectifies to 12V DC he says that the winding on the transformer should be 15-0-15v AC

Also for the USB player that needs 5V DC , the winding needs to be 9-0V AC

So should I order what my friend says or what the circuit maker says

The circuit maker asks for
45-0-45
12-0-12
12-0
5-0


My friend insists on
48-0-48
15-0-15
12-0
9-0

Regards

 

[magma]

48-0-48
Is pushing it if you are gonna use 60v caps innthe power supply board

Btw
A 40-0-40
700 va torroid
I have measured giving a 55v rectified op


Listen to the circuit maker
He knows his stuff

 

[sdk]

The circuit maker recommends voltages from 45v to 55v with minimum of 8A, depending on output wanted.

I want to be conservative at 45v 8A

The caps are 10,000uf 100v for safety margin

There is a strong possibility that the Toshiba transistors might be fake, good quality or bad quality fakes, regardless of my dealers assurances that they are good ones

So I don't want to drive them too hard.

 

[jls001]

The circuit maker recommends voltages from 45v to 55v with minimum of 8A, depending on output wanted.

I want to be conservative at 45v 8A

The caps are 10,000uf 100v for safety margin

There is a strong possibility that the Toshiba transistors might be fake, good quality or bad quality fakes, regardless of my dealers assurances that they are good ones

So I don't want to drive them too hard.

45 transformer secondary voltage will give you ~63 Volts rectified DC. 77.77 VDC if using 55V secondary. The voltage of the secondary winding must be chosen based on the Safe Operating Area (SOA) of the semiconductors being used (after budgeting some headroom). Your cap voltage has good margin.

Please buy semiconductors from reputed sources only.

A local source of toroidal transformers is Dayanand in Gurgaon East near Film City (+919833429845). I have bought a few custom toroidals and R Cores from him.

 

[sdk]

Thank you so much for your reply.

Do you know any reputable dealers in Mumbai for semiconductors?

Regards

 

[sdk]

If .you know the specs
A mail
To
torotrans in Pune
Or
Electro magnetic devices banglore

Should get you a reply

Both are good manufacturers and supply correctly rated transformers

Google the above names
You will arrive on their website

For smaller supplies like preamps an
Rcore is good

Fir larger supplies like powe amps a torroid is good

The designer whose power board you buy will be a better judge of which kind of transformer you should buy

Hi magma,

Do you have any contact details for Electro magnetic devices banglore or a website

My search leads to a company making heavy machinery in Bangalore or a company called miracle in Hyderabad

Torotrans has frightened me with a quote of about Rs 5800 each

Regards

 

[saikatbiswas82]

Hi magma,

Do you have any contact details for Electro magnetic devices banglore or a website

My search leads to a company making heavy machinery in Bangalore or a company called miracle in Hyderabad

Torotrans has frightened me with a quote of about Rs 5800 each

Regards

You may contact Mr. Suresh Hebber from EMD. PM sent.

 

[rrunner]

Hi,

I am trying to build a tube amp from a generic kit purchased online.I am about to procure the power amplifiers required for this locally in Hyderabad.
It would be of great help to me if someone can decipher and tell me the specs of the input and output transformer as well as additional parts(inputs,vol control etc) to make this work.Will a torroidal transformer help in this build.
Thx

16.13US $ 10% OFF|Aiyima 6n1+6p1 Valve Stereo Amplifier Board Vacuum Tube Amplifiers Filament Ac Power Supply + 3pcs Tubes - Home Theater Amplifiers - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

 

[rrunner]

sorry for the double post.

 

[sdk]

Hi,

I am trying to build a tube amp from a generic kit purchased online.I am about to procure the power amplifiers required for this locally in Hyderabad.
It would be of great help to me if someone can decipher and tell me the specs of the input and output transformer as well as additional parts(inputs,vol control etc) to make this work.Will a torroidal transformer help in this build.
Thx

16.13US $ 10% OFF|Aiyima 6n1+6p1 Valve Stereo Amplifier Board Vacuum Tube Amplifiers Filament Ac Power Supply + 3pcs Tubes - Home Theater Amplifiers - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

Hi,

Best of luck for your build!

From my short experience of making a diy amplifier i have a few tips from my experience, YMMV.

Do not build anything till you get all the parts in hand. I can't repeat this enough. Running around dealers to get that one missing component is most frustrating

Once you have got all the components together only then start looking for cabinets to fit them in or make one to your requirement.

The other way is to buy a cabinet that's available and then choose component boards to fit inside , if you are trying to build on a budget

For people building amps that require heatsinks, getting the cabinet that's available in their market is most important to determine the size of heatsink to buy.

If like me you believe that the largest heatsink will run your transistors the coolest then getting a suitable cabinet to house the heatsink that you've already attached becomes a challenge

Whatever you do, buy the transformer first, as in my experience that's the most difficult part if you want one piece wound with your choice of secondaries.

You may have to take the transformer around to see how to fit inside the cabinets that you shortlist to find out if the rest of your boards fit inside

Your item listing shows the transformer windings and amps required. Just show that printout to your transformer guy and he will make one accordingly. Picture attached

Getting it first is most important to test your circuits along with a series board or you find troubleshooting difficult.

If you find a good chap to make you one then do share his contact details here too and ask him if he is willing to courier to various parts of the country

Regards

 

[rrunner]

Hi,
Thanks for your inputs.On second thought I realized that I have a couple of power inverters lying around unused(one is Amaron Tribal 850va home inverter and other is wipro computer UPS 800va), I am now contemplating the idea of salvaging those transformers and reuse them if they are somewhat compatible.All I am looking for is a vintage feel of glowing tubes and half decent sound quality in a budget build of <5000Rs.I may even build a wooden chassis with 5mm plywood if everything works out well.

 

[sdk]

I'm copying my post from my other thread here too


Collected my transformer from the manufacturer

A very heavy monster built to the dimensions that I had specified, due to my cabinet and board dimensions

I feel he's done a great job

Will test for voltages later, after my back and neck recovers from lugging them back home.

It took longer than usual because I was constrained by the space I had and the core required by him.

He had to specifically order narrow and tall cores for me. Compared to the wider and shorter cores that people generally order to make slim looking amps

He's done a great job except for two things that I wanted

One was a copper shield around the primary connected to ground. Since he almost never gets requests for that, he forgot, so he added it at the end over the secondaries. At least it will prevent leakage. At the cost of safety, if the primary shorts with no foil and connection to ground and leakage between primary and secondary.

I also wanted a thermal cut off switch. He said that he never gets orders for those either and could not source them in time. He asked me to add an external one later.

From what I saw, he's very busy with hundreds of EI as well as toiroids being packed during every visit.

If the core is in stock, he promises delivery within a week, if he has to order uncommon cores then almost two weeks like mine

 

[sdk]

Got a couple of PMs asking for the contact details of the chap who made my transformer, so I thought I'll put it here too for others who may be interested

Mr Sasi Kumar
#098690 38363
Be Tech India
No. 68, 2nd floor,
Sangam Society, Laxmi Nagar,
Goregaon West, Mumbai,
Maharashtra 400047

I have no affiliation of any sort with him

 

[tcpip]

Got a couple of PMs asking for the contact details of the chap who made my transformer, so I thought I'll put it here too for others who may be interested

Mr Sasi Kumar
#098690 38363
Be Tech India
No. 68, 2nd floor,
Sangam Society, Laxmi Nagar,
Goregaon West, Mumbai,
Maharashtra 400047

I have no affiliation of any sort with him

Thanks for this contact. I've never been able to locate any toroidal xfmr maker in Bombay till you gave this pointer.

However, it's really easy to get an xfmr done from Torotrans in Pune. He answers phone calls and emails, sends a quote over email, is DIY and hobbyist friendly, and will ship the item anywhere in India. He is fully conversant with adding an electrostatic shield in the xfmr, and will do custom jobs with the exact secondaries you want. He can deliver dual-secondary windings or centre-tapped three-wire secondaries, whatever you want. He has the ability to build 2KVA or larger xfmrs too, so power rating is not a limitation.

I've gotten one 1KVA xfmr built by him, and will ask him for some more units soon. My xfmr source hunt has ended.

 

[surfatwork]

I agree. Mahesh at torotrans is a good source at a fair price. Have bought multiple transformers from.him. Only thing is, he sometimes forgets your order and you have to chase a bit.

 

[tcpip]

I agree. Mahesh at torotrans is a good source at a fair price. Have bought multiple transformers from.him. Only thing is, he sometimes forgets your order and you have to chase a bit.

This is the bane of the hobbyist. Since we give our vendors such tiny volumes of business, they tend to forget us.

I am waiting for the last 3 weeks for Aminder (TheAudioCrafts) to tell me whether he has some inductors I want to order. I am sure he's forgotten by now. I had sent him one reminder some time back, to which I got no reply. I like the person, and I'll keep buying from him. It's just that they tend to forget, or not respond at all, and so on. In the meantime, I ordered those 4 inductors (for the BSC of the Asawari 4) from Parts Express, and they reached me, I fitted them, got excellent results, and closed the project. And truth be told, the inductors I have bought from Aminder in the past are better than the ones I got from Parts Express. What does one do?