Design Me A Transformer, I Will Pay

I have tried to figure out how to do this but my education lacks. What do people like me do when they need something done they can't do ? Pay someone. 

I need an audio transformer, actually a center tapped choke. I can't seem to source it so custom mad, oh well. You get what you pay for. 

This has to be high quality for audio, not saturate or any of that and I need a low DCR. 

This is the configuration;

Version 4
SHEET 1 880 680
WIRE 256 48 64 48
WIRE 368 48 256 48
WIRE 256 128 160 128
WIRE -32 176 -32 16
WIRE 64 176 64 144
WIRE 64 176 -32 176
WIRE 64 208 64 176
WIRE 368 208 256 208
WIRE 160 272 160 128
WIRE 256 304 256 208
WIRE 256 304 64 304
FLAG 160 272 0
SYMBOL ind 240 32 R0
SYMATTR InstName L1
SYMBOL ind 240 112 R0
SYMATTR InstName L2
SYMBOL pnp 0 48 R0
SYMATTR InstName Q1
SYMBOL pnp 0 304 M180
SYMATTR InstName Q2

The load consider to be four ohms from end to end. I need to push +30 volts into one end and have -30 volts come out the other end, able to feed low impedance. I need it to do that efficiently at least from 20-20,000. 

How much ? Or do you want in on the deal ? They will go for like two grand so just 5% is a Cnote. If you're any kind of an audiophile I could just give you one of these amps. There really is nothing like them on the market. 

If you can't get my email with your client software it is JURB6006 at gmail, and of course dot com. You can reply here, just how much do you want to do this ? I need wire size, number of turns and the core specifics. I know the basics about transformers but this is beyond me. Frequency response flat and all that, I have no clue. An RF transformer I could tune with caps, a power transformer, actually I tried using one once and the performance was not good. 

I used to do this scrapping tube amps that had 4 and 16 ohm outputs with good results. The 4 is the center tap and the 0 and 16 are the ends. thing is if I go too high in power I am inducing a hell of alot of voltage into the "primary" which isn't really anymore. But it can arc and break down insulation. I would consider them but for that, I would need them in the higher wattage range. Without the "primary" it should save money and weight. 

I have it mostly figured out except this. Well and one thing i want to do to the tone controls, at the highest turnover frequency the treble will have +/- 20dB range, if the turnover is lowered by the control to boost more of the spectrum I want to decrease the range so people don't blow their tweeters. I might make it switchable - "treble protection". Other than that over half the math is done and I am all the way back to the tone board, it is designed but I want a differential drive to the output circuit. 

Interested in this ? I am not hard to find.

On Friday, September 6, 2019 at 2:33:42 PM UTC-4, jurb...@gmail.com wrote:
> I have tried to figure out how to do this but my education lacks. What do people like me do when they need something done they can't do ? Pay someone. 
> 
> I need an audio transformer, actually a center tapped choke. I can't seem to source it so custom mad, oh well. You get what you pay for. 
> 
> This has to be high quality for audio, not saturate or any of that and I need a low DCR. 
> 
> This is the configuration;
> 
> Version 4
> SHEET 1 880 680
> WIRE 256 48 64 48
> WIRE 368 48 256 48
> WIRE 256 128 160 128
> WIRE -32 176 -32 16
> WIRE 64 176 64 144
> WIRE 64 176 -32 176
> WIRE 64 208 64 176
> WIRE 368 208 256 208
> WIRE 160 272 160 128
> WIRE 256 304 256 208
> WIRE 256 304 64 304
> FLAG 160 272 0
> SYMBOL ind 240 32 R0
> SYMATTR InstName L1
> SYMBOL ind 240 112 R0
> SYMATTR InstName L2
> SYMBOL pnp 0 48 R0
> SYMATTR InstName Q1
> SYMBOL pnp 0 304 M180
> SYMATTR InstName Q2
> 
> The load consider to be four ohms from end to end. I need to push +30 volts into one end and have -30 volts come out the other end, able to feed low impedance. I need it to do that efficiently at least from 20-20,000. 
> 
> How much ? Or do you want in on the deal ? They will go for like two grand so just 5% is a Cnote. If you're any kind of an audiophile I could just give you one of these amps. There really is nothing like them on the market. 
> 
> If you can't get my email with your client software it is JURB6006 at gmail, and of course dot com. You can reply here, just how much do you want to do this ? I need wire size, number of turns and the core specifics. I know the basics about transformers but this is beyond me. Frequency response flat and all that, I have no clue. An RF transformer I could tune with caps, a power transformer, actually I tried using one once and the performance was not good. 
> 
> I used to do this scrapping tube amps that had 4 and 16 ohm outputs with good results. The 4 is the center tap and the 0 and 16 are the ends. thing is if I go too high in power I am inducing a hell of alot of voltage into the "primary" which isn't really anymore. But it can arc and break down insulation. I would consider them but for that, I would need them in the higher wattage range. Without the "primary" it should save money and weight. 
> 
> I have it mostly figured out except this. Well and one thing i want to do to the tone controls, at the highest turnover frequency the treble will have +/- 20dB range, if the turnover is lowered by the control to boost more of the spectrum I want to decrease the range so people don't blow their tweeters. I might make it switchable - "treble protection". Other than that over half the math is done and I am all the way back to the tone board, it is designed but I want a differential drive to the output circuit. 
> 
> Interested in this ? I am not hard to find.

There are many hundreds of custom design houses, and they do take orders for prototype small quantities like onesies. They have the manufacturing down to a triviality, usually working out the details in real time on their in house CAD in a few minutes of phone conversation. You just need to know what you want and be prepared to answer their questions about the application. Looking their quote spec sheet over beforehand should help. The product doesn't cost that much at all. Here is one as an example, I've never used them and don't know anything abut them- they're just an example:
https://www.custommag.com/custom-transformer-design

On Fri, 6 Sep 2019 11:33:37 -0700 (PDT), jurb6006@gmail.com wrote:

>I have tried to figure out how to do this but my education lacks. What do people like me do when they need something done they can't do ? Pay someone. 
>
>I need an audio transformer, actually a center tapped choke. I can't seem to source it so custom mad, oh well. You get what you pay for. 
>
>This has to be high quality for audio, not saturate or any of that and I need a low DCR. 
>
>This is the configuration;
>
>Version 4
>SHEET 1 880 680
>WIRE 256 48 64 48
>WIRE 368 48 256 48
>WIRE 256 128 160 128
>WIRE -32 176 -32 16
>WIRE 64 176 64 144
>WIRE 64 176 -32 176
>WIRE 64 208 64 176
>WIRE 368 208 256 208
>WIRE 160 272 160 128
>WIRE 256 304 256 208
>WIRE 256 304 64 304
>FLAG 160 272 0
>SYMBOL ind 240 32 R0
>SYMATTR InstName L1
>SYMBOL ind 240 112 R0
>SYMATTR InstName L2
>SYMBOL pnp 0 48 R0
>SYMATTR InstName Q1
>SYMBOL pnp 0 304 M180
>SYMATTR InstName Q2
>
>The load consider to be four ohms from end to end. I need to push +30 volts into one end and have -30 volts come out the other end, able to feed low impedance. I need it to do that efficiently at least from 20-20,000. 
>
>How much ? Or do you want in on the deal ? They will go for like two grand so just 5% is a Cnote. If you're any kind of an audiophile I could just give you one of these amps. There really is nothing like them on the market. 
>
>If you can't get my email with your client software it is JURB6006 at gmail, and of course dot com. You can reply here, just how much do you want to do this ? I need wire size, number of turns and the core specifics. I know the basics about transformers but this is beyond me. Frequency response flat and all that, I have no clue. An RF transformer I could tune with caps, a power transformer, actually I tried using one once and the performance was not good. 
>
>I used to do this scrapping tube amps that had 4 and 16 ohm outputs with good results. The 4 is the center tap and the 0 and 16 are the ends. thing is if I go too high in power I am inducing a hell of alot of voltage into the "primary" which isn't really anymore. But it can arc and break down insulation. I would consider them but for that, I would need them in the higher wattage range. Without the "primary" it should save money and weight. 
>
>I have it mostly figured out except this. Well and one thing i want to do to the tone controls, at the highest turnover frequency the treble will have +/- 20dB range, if the turnover is lowered by the control to boost more of the spectrum I want to decrease the range so people don't blow their tweeters. I might make it switchable - "treble protection". Other than that over half the math is done and I am all the way back to the tone board, it is designed but I want a differential drive to the output circuit. 
>
>Interested in this ? I am not hard to find.


Try  todd <at> newava.com. I recently sent him a spec for a special
toroidal power transformer and he came back with a nice proposal and
decent pricing. He's done some good stuff for me before.

jurb6006@gmail.com wrote...
>
 You don't need a transformer, you need power amplifiers
 capable of 60 Vp-p and 15A.  That's 900 watts.  Or maybe
 two 450-watt amps.  There are class-D designs that can
 handle that.  In the event you have slightly miscalculated,
 there are Chinese sellers of souped-up class-D chip eval
 designs that can handle those power levels, selling for
 quite low prices on eBay.  I have purchased and received
 a selection, and they're not so bad.  Transformers suck.  


-- 
 Thanks,
    - Win

Winfield Hill while way out of his depth wrote:

> 
>
>  You don't need a transformer, you need power amplifiers
>  capable of 60 Vp-p and 15A.  That's 900 watts.  Or maybe
>  two 450-watt amps.  There are class-D designs that can
>  handle that.  In the event you have slightly miscalculated,
>  there are Chinese sellers of souped-up class-D chip eval
>  designs that can handle those power levels, selling for
>  quite low prices on eBay.  I have purchased and received
>  a selection, and they're not so bad.  Transformers suck.  
> 
> 
>

** Hummmm - use a class D chip amp or two plus no doubt a high falutin' SMPS *instead* of a simple iron core transformer. 

 That IS a damn novel idea. 




....  Phil 

On a sunny day (6 Sep 2019 19:12:15 -0700) it happened Winfield Hill
<winfieldhill@yahoo.com> wrote in <qkv3lv02btn@drn.newsguy.com>:

>jurb6006@gmail.com wrote...
>>
> You don't need a transformer, you need power amplifiers
> capable of 60 Vp-p and 15A.  That's 900 watts.

I presume you mean 60 Veff??

(60 / (2 * sqrt(2) ) ) * 15 = 318.198052 W

Wpeakpeak??
;-)

(Have not read the OP)

donald where's your trousers wrote:

----------------------------------
> Winfield Hill
>
> 
 >>
> > You don't need a transformer, you need power amplifiers
> > capable of 60 Vp-p and 15A.  That's 900 watts.
> 
> I presume you mean 60 Veff??



** Win is off with the fairies, again.

  60Vp-p = 21.2V rms. 

  With a 4 ohm load that is 112 watts. 

 

> (Have not read the OP)


** Or even woken up ? 



......  Phil 

Phil Allison wrote...
>
>** Win is off with the fairies, again.
>
>  60Vp-p = 21.2V rms. 
>  With a 4 ohm load that is 112 watts. 

 Dunno what the O.P. is doing, but I always
 like to think in terms of the max DC power.
 Certainly when using a class-D MOSFET stage,
 you're always considering the Vmax and Imax.
 Pmax Pavg Pwhatever, posh, who cares?


-- 
 Thanks,
    - Win

On Fri, 6 Sep 2019 19:49:42 -0700 (PDT), Phil Allison
<pallison49@gmail.com> wrote:

>Winfield Hill while way out of his depth wrote:
>
>> 
>>
>>  You don't need a transformer, you need power amplifiers
>>  capable of 60 Vp-p and 15A.  That's 900 watts.  Or maybe
>>  two 450-watt amps.  There are class-D designs that can
>>  handle that.  In the event you have slightly miscalculated,
>>  there are Chinese sellers of souped-up class-D chip eval
>>  designs that can handle those power levels, selling for
>>  quite low prices on eBay.  I have purchased and received
>>  a selection, and they're not so bad.  Transformers suck.  
>> 
>> 
>>
>
>** Hummmm - use a class D chip amp or two plus no doubt a high falutin' SMPS *instead* of a simple iron core transformer. 
>
> That IS a damn novel idea. 
>
>
>
>
>....  Phil 
>

TPA3255 looks great. It's good for 600w mono or 300 stereo, for under
$10. I've just got to figure out an elegant way to heat sink it.

I can get a MeanWell 600 watt 48V power supply for something crazy
like $80.

On 9/6/2019 1:33 PM, jurb6006@gmail.com wrote:
> I have tried to figure out how to do this but my education lacks. What do people like me do when they need something done they can't do ? Pay someone.
> 
> I need an audio transformer, actually a center tapped choke. I can't seem to source it so custom mad, oh well. You get what you pay for.
> 
> This has to be high quality for audio, not saturate or any of that and I need a low DCR.
> 
> This is the configuration;
> 
> Version 4
> SHEET 1 880 680
> WIRE 256 48 64 48
> WIRE 368 48 256 48
> WIRE 256 128 160 128
> WIRE -32 176 -32 16
> WIRE 64 176 64 144
> WIRE 64 176 -32 176
> WIRE 64 208 64 176
> WIRE 368 208 256 208
> WIRE 160 272 160 128
> WIRE 256 304 256 208
> WIRE 256 304 64 304
> FLAG 160 272 0
> SYMBOL ind 240 32 R0
> SYMATTR InstName L1
> SYMBOL ind 240 112 R0
> SYMATTR InstName L2
> SYMBOL pnp 0 48 R0
> SYMATTR InstName Q1
> SYMBOL pnp 0 304 M180
> SYMATTR InstName Q2
> 
> The load consider to be four ohms from end to end. I need to push +30 volts into one end and have -30 volts come out the other end, able to feed low impedance. I need it to do that efficiently at least from 20-20,000.
> 
> How much ? Or do you want in on the deal ? They will go for like two grand so just 5% is a Cnote. If you're any kind of an audiophile I could just give you one of these amps. There really is nothing like them on the market.
> 
> If you can't get my email with your client software it is JURB6006 at gmail, and of course dot com. You can reply here, just how much do you want to do this ? I need wire size, number of turns and the core specifics. I know the basics about transformers but this is beyond me. Frequency response flat and all that, I have no clue. An RF transformer I could tune with caps, a power transformer, actually I tried using one once and the performance was not good.
> 
> I used to do this scrapping tube amps that had 4 and 16 ohm outputs with good results. The 4 is the center tap and the 0 and 16 are the ends. thing is if I go too high in power I am inducing a hell of alot of voltage into the "primary" which isn't really anymore. But it can arc and break down insulation. I would consider them but for that, I would need them in the higher wattage range. Without the "primary" it should save money and weight.
> 
> I have it mostly figured out except this. Well and one thing i want to do to the tone controls, at the highest turnover frequency the treble will have +/- 20dB range, if the turnover is lowered by the control to boost more of the spectrum I want to decrease the range so people don't blow their tweeters. I might make it switchable - "treble protection". Other than that over half the math is done and I am all the way back to the tone board, it is designed but I want a differential drive to the output circuit.
> 
> Interested in this ? I am not hard to find.
> 

If I understand your configuration correctly, you have an 
autotransformer driven in a class B connection at the ends. The 
transformer will need to have the thinnest laminations you can get in 
order to handle the 20kHz. You will need to have enough laminations 
(core) to not saturate at 20Hz. But the designer should know that. You 
will need a wire size to handle the current (about 10ARMS) without 
generating excessive heat and/or without excessive resistance.

I suggest the following specifications for your transformer:

Autotransformer (bifilar winding)
20Hz - 20kHz
Current - 10Arms
Voltage rating is not a problem. Even the wire enamel can handle it.
Suggested lamination source: Thomas & Skinner (No connection with them).

I designed transformers, but have no experience with audio.