Question about SSL Tech's power supply for SSL 9k,

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

nathun

Well-known member
Joined
Jun 4, 2004
Messages
58
Location
Mobile Al.
Do I need to build mutliple power supplies if I'm putting more than one channel in a rack, or can I use multiple pre amps with just one supply. Whats the most Pre's I can safely power from one supply? (I really want to build 8, fingers crossed). Also if anyone has the bargraph module schematic,that Keith made, (or knows where i can find it) I'd appreciate the info. Thanks. Nathan :green:
 
Hi Nathan,

Well, it depends on what preamp you're dealing with. If it's a simple single op-amp pre you may be able to power a whole rack, but if its's a Neevee-style Class-A behemoth with current-hungry rack-warming output stages, you'll need to be more careful.

Let us know what you're racking, and I'll explain how to measure the current draw per-channel.

Keiths PSU uses 1A regulator IC's, but this doesn't mean that they can supply 1A- it depends on the rating of the transformer.

Mark
 
I was thinking of doing the SSL 9000 (9K) pre and putting about four in a rack. Thanks for any help you guys can give. Nathan
 
if you mean schematics please find it here :

http://www.mutekki.com/forum/phpBB2/viewtopic.php?t=47
 
[quote author="Rob Flinn"]Thanks Mark,

I`m still confused by this since the 9K uses +/-18v for the 5534 & +/-15v for the TL052, & this PSU board only supplies +/- 18v.[/quote]
bump
Any chance of the forum asking this - as it's stumping me as well
 
[quote author="uk03878"][quote author="Rob Flinn"]Thanks Mark,

I`m still confused by this since the 9K uses +/-18v for the 5534 & +/-15v for the TL052, & this PSU board only supplies +/- 18v.[/quote]
bump
Any chance of the forum asking this - as it's stumping me as well[/quote]
soory found the answer courtesy of Mark B.

"
IIRC the +/-15V supply is only used for the output servo, so a pair of low-current regulators such as 78L15 and 79L15's could be mounted on a small piece of Veroboard/stripboard with a feed from the +/-18V.

Two things to watch out for- supplying a 78L15 or 79L15 with +/-18V means that there is only a 3V differential between input an output. The minimum stated voltage input for these 15 regulators is 17.5V, and I've had some funny experiences with too-low-a drop out voltage, so it may be better to supply these 15V regulators from before the +/-18V regulators- i.e. directly after the rectifier/filter capacitors.

Also, some regs don't like too-small a current draw, so it may be an idea to use the +/-15V rail to supply a front panel LED. Place an LED with a series resistor from +15V to -15V. For a standard red LED use about 4k7 to 10k.
"
thanks....
 
the tl052 is rated absolute max V at +-18v, the max operating V is +- 15v. you would be riding the rails pretty hard and likely to burn the sucker out that's why there is 15v rails for it. I see that it consumes much more power too. Why not put a tl072/82 in there and use the 18v rails? same with the tl051, change to tl071? I also read that there is no realistic gain from using the tl05x over the tl07x/8x in audio frequencies. anybody care to try? doesn't someone make this PCB on the forum? maybe i should volunteer to try this out..?

:thumb: :guinness:
 
Yes.. the 052 is the low-offset version, hance the call for an 052. -You can run a pair from a 78L15 and 79L15 sub-regulator pair... or by all means stick an 072 in there and you'll still have a reasonably good DC servo, but not as good as with an 052...

Keith
 
does anyone know how much "better" they are in the circuit than the tl07xs? testing numbers?

i also found this while looking for datasheets to refresh my memory:

http://www.dself.dsl.pipex.com/ampins/webbop/052.htm

:thumb:
 
> how much "better" they are in the circuit than the tl07xs?

According to Doug's page: {052} Offset voltage is 0.65 mV typ, 1.5 mV max, compared with the TL072's 3mV typ, 10mV max. It has half the bias current of the TL072.

Very significantly better DC error correction. The 07x will work, but the 052 much better.

The supply current for this preamp is under 40mA per channel. 8 channels would be 300mA. I do not see this PS schematic, but assuming it is conventional you should use a 600mA to 1A transformer, and fairly good size heatsinks on the regulators, like 2 inches 5cM square.

The drain of the 052 is so small I would just use 15V Zeners with say 1K resistors for one channel, 150 ohm resistors for a +/-15V supply for 8 channels.
 
Back
Top