Voltage distribution using series primaries is at the mercy of secondary loading when using two separate transformers.
Separate transformers with series primaries (or even parallel primaries) is not the solution to balancing the secondary side drive.
DUG Thanks for the Heads UP 
I have attached the latest using the LL1592. PCB SIZE : 120mm x 150mm.
http://www.lundahl.se/wp-content/uploads/datasheets/1592.pdf
DoctorMord Luv the moblie setup !
I have attached the latest using the LL1592. PCB SIZE : 120mm x 150mm. http://www.lundahl.se/wp-content/uploads/datasheets/1592.pdf
DoctorMord Luv the moblie setup !
Attachments
I thought I read somewhere that a heat sink was mandatory on this chip but I went back to the data sheet and could not find the reference to that.
However.
At 150deg C max and 24.4deg C/W (junction to board) and 25 C ambient.
That results in a maximum of about 7W of power dissipation.
Based somewhat loosely on Figure 7, it would be best to watch your output power when running without a heat sink.
However.
At 150deg C max and 24.4deg C/W (junction to board) and 25 C ambient.
That results in a maximum of about 7W of power dissipation.
Based somewhat loosely on Figure 7, it would be best to watch your output power when running without a heat sink.
Attachments
I just found this lovely natural convection heat sink while enjoying Monday Night Football (plus a couple beers 
)
https://www.alphanovatech.com/dxf/N.pdf
I plan on using the N19-25B Model. ~16C/W. My current Speakers are 4ohm 93db. I don't need much in the way of cooling. I currently drive my speakers with an Electra Fidelity 45 Set amp.
Hologram M4 ? SPATIAL AUDIO
)https://www.alphanovatech.com/dxf/N.pdf
I plan on using the N19-25B Model. ~16C/W. My current Speakers are 4ohm 93db. I don't need much in the way of cooling. I currently drive my speakers with an Electra Fidelity 45 Set amp.
Hologram M4 ? SPATIAL AUDIO
A Couple different PCB Layouts for your consideration..
A layout using the TDK ERU 25 Inductor.
http://en.tdk.eu/inf/30/db/ind_2008/b82559_a025.pdf
A layout using the Clarity TC600 85uf Capacitor.
ClarityCap TC600 Series Film Capacitor
I have also designed an amp based on the TDA7297 using this Clarity Cap.
Enjoy
A layout using the TDK ERU 25 Inductor.
http://en.tdk.eu/inf/30/db/ind_2008/b82559_a025.pdf
A layout using the Clarity TC600 85uf Capacitor.
ClarityCap TC600 Series Film Capacitor
I have also designed an amp based on the TDA7297 using this Clarity Cap.
Enjoy
Attachments
Too bad TDK doesn't put a L vs I graph in the data sheet.
I would add it to my list if the line looked good.
A Couple different PCB Layouts for your consideration..
..
A layout using the Clarity TC600 85uf Capacitor.
ClarityCap TC600 Series Film Capacitor
I have also designed an amp based on the TDA7297 using this Clarity Cap.
Enjoy
The cap looks excellent for tube stuff but I agree with 5th element in that I question the use of a 600V cap. Even though it has an "ERS 3.0 mOhm" it is still only 85uF.
So an update.
I bought a nice shiny case from Aliexpress to put this in. I was quite surprised by the affordability of this as the entire case, shipped in under a week via DHL came to around £68.
Having done a lot of my own work on aluminium, both in terms of cutting it myself, having some laser cut and also doing a lot of brushed finishes. I can say it was worth every penny.
The case itself came flat-packed, with all screws and rubber feet included. Above you can see that the back panel has a cutout for an IEC connector. The case came with a fused connector too.
As you can see there is quite a lot of space left inside the case after the amplifier PCB. Mostly the width and height were required to fit in all the connectors on the back, but the length of the case was chosen specifically to allow for a suitable power supply at some point.
This shot gives an indication of how I've handled the heat sinking. Basically each chip has a small square of copper bar covering the thermal pad. This allows for greater separation between the chips and the heat sink above. As you can see I haven't exactly put a 'heat sink' as per say in place, but a thick aluminium bar. The bar is 15mm x 15mm, tapped with a 6mm thread in two places. This anchors the bar to the copper bar separators and keeps the chips cool. And if I need any extra performance I can easily put a heat sink on top of the 15mm bar.
With the lid on.
And on the Hi-fi rack, complete with colour changing illuminated feet. (Ignore the dust). The feet turn on and off when the amplifier is triggered from the preamp above.
I bought a nice shiny case from Aliexpress to put this in. I was quite surprised by the affordability of this as the entire case, shipped in under a week via DHL came to around £68.
Having done a lot of my own work on aluminium, both in terms of cutting it myself, having some laser cut and also doing a lot of brushed finishes. I can say it was worth every penny.
The case itself came flat-packed, with all screws and rubber feet included. Above you can see that the back panel has a cutout for an IEC connector. The case came with a fused connector too.
As you can see there is quite a lot of space left inside the case after the amplifier PCB. Mostly the width and height were required to fit in all the connectors on the back, but the length of the case was chosen specifically to allow for a suitable power supply at some point.
This shot gives an indication of how I've handled the heat sinking. Basically each chip has a small square of copper bar covering the thermal pad. This allows for greater separation between the chips and the heat sink above. As you can see I haven't exactly put a 'heat sink' as per say in place, but a thick aluminium bar. The bar is 15mm x 15mm, tapped with a 6mm thread in two places. This anchors the bar to the copper bar separators and keeps the chips cool. And if I need any extra performance I can easily put a heat sink on top of the 15mm bar.
With the lid on.
And on the Hi-fi rack, complete with colour changing illuminated feet. (Ignore the dust). The feet turn on and off when the amplifier is triggered from the preamp above.
Attachments
It's this store.
Chassis / enclosure - Shop Cheap Chassis / enclosure from China Chassis / enclosure Suppliers at Weiliang Audio on Aliexpress.com
They have lots of nice stuff with free shipping.