Hypex were packaging up the rather large order this morning so should be with the courier today and arrive later this week 
On a more serious note, we do need to confirm recommended power supply for this. I do have a small personal concern with the HxR regulators: the latest spec has a much reduced power allowance which seems a bit strange, and I know some who use them have had issues recently.
I'd have to check and believe the current requirements for the SMD version of the LM4562 is rather low, so hopefully there won't be any issues driving 4x LM4562 per regulator pair...
The last thing I want is this to be an issue of course, so I hope I can get some reassurance that everything will be fine.
Jan, do you know if you can ask Bruno regarding the power supply and regulator points? As it isn't a sanctioned "Hypex" product per se, I can't ask them myself...
On a more serious note, we do need to confirm recommended power supply for this. I do have a small personal concern with the HxR regulators: the latest spec has a much reduced power allowance which seems a bit strange, and I know some who use them have had issues recently.
I'd have to check and believe the current requirements for the SMD version of the LM4562 is rather low, so hopefully there won't be any issues driving 4x LM4562 per regulator pair...
The last thing I want is this to be an issue of course, so I hope I can get some reassurance that everything will be fine.
Jan, do you know if you can ask Bruno regarding the power supply and regulator points? As it isn't a sanctioned "Hypex" product per se, I can't ask them myself...
I know Andrew, it's just that the latest batch seem to have a more limited regulation capability, and a new datasheet dated 1st April this year has been released detailing these changes.
The pre-amp design is before of course.
Hopefully, it's a non-issue here.
Those values are a little hyped
The old datasheet says for absolute maximum values:
Input voltage: 60V
Output current: 600mA
Power Dissipation: 2W
However, the newer datasheet for the same absolute maximum values states the same values except for Power Dissipation which is now halved to 1W.
There's an additional note which wasn't present in the previous datasheet:
"Please design your application in such a manner that the power dissipation of the HxR will not exceed
the given values. The thermal dissipation can be calculated using the following formula: (Vin – Vout) * Iin"
In addition, there's a Thermal dissipation under general performance data which says typical 0.5W, max 0.75W. This wasn't specified in the earlier datasheet at all.
So the reduced power combined with the new note to really point it out shows that it's easy to go over this limit without asking it to do something unreasonable.
Looking at the LM4562, the input current is pretty constant for a given voltage regardless of load - around just under 10mA with a +/- 12V supply. So that means around 40mA with four ICs. Which would equate to around 0.25W dissipated assuming an 18V supply to the regs, so I guess we're OK...
Do we have a recommended design for the power source?
Sorry, not sure what you mean. Audio level? People on the group buy?
I have a Farnell one if that helps - the same BOM list I supplied to Quick Circuits for the assembly.
From the latest datasheet, the recommended values are:
Min: 15V
Typical: 18V
Max: 25V
The absolute max is 60V, but I think we want to stay as close as possible to minimum to minimise voltage drop which translates to the thermal heat and the potential issues.
Attached a BOM too. There are two tabs, the original BOM with MELFs, and a revised tab with MELFs only where necessary and swapping the TL72 with another LM4562 due to noise.
Min: 15V
Typical: 18V
Max: 25V
The absolute max is 60V, but I think we want to stay as close as possible to minimum to minimise voltage drop which translates to the thermal heat and the potential issues.
Attached a BOM too. There are two tabs, the original BOM with MELFs, and a revised tab with MELFs only where necessary and swapping the TL72 with another LM4562 due to noise.
I am confused by the mention of design for a power source.
I was going to use a small transformer from the spares box, 230v primary (mains) to 15-0-15v secondary
(6 VA per winding) connected to J6 on the pcb..
Rectification provided by the on board D1 to D4 (RSD1) smoothing by the on board C12 to C15 & R26,R28 and regulation by Hypex U4 & U5.
Is this too simplistic?
I was going to use a small transformer from the spares box, 230v primary (mains) to 15-0-15v secondary
(6 VA per winding) connected to J6 on the pcb..
Rectification provided by the on board D1 to D4 (RSD1) smoothing by the on board C12 to C15 & R26,R28 and regulation by Hypex U4 & U5.
Is this too simplistic?
for a 1W limit on the regulators take care to check actual current consumption of the boards and determine actual regulator dissipations.
eg +-18Vdc supplied from a nominal 12-0-12Vac transformer and passing 60mA through the regulator one ends up with (18-12)V * 0.06A = 0.36W, well within the 1W permitted.
Using a 15-0-15Vac transformer increases dissipation to ~0.63W
I'd suggest we don't use an 18Vac transformer.
eg +-18Vdc supplied from a nominal 12-0-12Vac transformer and passing 60mA through the regulator one ends up with (18-12)V * 0.06A = 0.36W, well within the 1W permitted.
Using a 15-0-15Vac transformer increases dissipation to ~0.63W
I'd suggest we don't use an 18Vac transformer.
Those values are a little hyped
The old datasheet says for absolute maximum values:
Input voltage: 60V
Output current: 600mA
Power Dissipation: 2W
However, the newer datasheet for the same absolute maximum values states the same values except for Power Dissipation which is now halved to 1W.
There's an additional note which wasn't present in the previous datasheet:
"Please design your application in such a manner that the power dissipation of the HxR will not exceed
the given values. The thermal dissipation can be calculated using the following formula: (Vin – Vout) * Iin"
In addition, there's a Thermal dissipation under general performance data which says typical 0.5W, max 0.75W. This wasn't specified in the earlier datasheet at all.
So the reduced power combined with the new note to really point it out shows that it's easy to go over this limit without asking it to do something unreasonable.
Looking at the LM4562, the input current is pretty constant for a given voltage regardless of load - around just under 10mA with a +/- 12V supply. So that means around 40mA with four ICs. Which would equate to around 0.25W dissipated assuming an 18V supply to the regs, so I guess we're OK...
Do we have a recommended design for the power source?
The datasheet was not correct. The 2W comes from the following: If you for instance draw ~100 mA with ~20V input from the HxR, one will draw 1200mW and dissipate 800mW. Together this is 2 Watts. The term 'power dissipation' was incorrectly used here.
You can easily calculate how hot your HrX will become using your ambient temperature, the thermal resistance and the power dissipation. For instance: (125 C Tjunc - 50 C Tamb) / 105 RθJA = 714 mW dissipation.
With 40 mA output and 18V input your will dissipate 240 mW. With 50 Tamb your HxR should be around (105 RθJA * 0.240 W) + 50 = ~75 degree Celsius. Correct me if i'm wrong...
Thanks- but looking for the other parts
checking lead spacing and such is not my cup of tea- already am going to have to desolder and jumper the SMD input R/C couplings to use the 6 input board.I don't know if anyone on here knows someone called Oleg Sydorov, but I've received an email from him selling vacuum tubes and other parts. The email came in on the group buy address which I've only ever mentioned here, and not in a harvestable format.
I've never had anything to do with him, so maybe someone's addressbook has been harvested for sending out emails?
I've never had anything to do with him, so maybe someone's addressbook has been harvested for sending out emails?