SL3 with External Power Supplies

[jmorcom]

Help! Does anyone know if SL3s were ever shipped with low voltage external PSUs?

Hi all,

I'm a newbie to this club, so hope this posts comes out OK...

I have an opportunity to buy a pair of Martin Logan SL3s which are about 8 years old. I have seen photos of the front and side of the speakers and they certainly look like SL3s.

However, the owner says they have external Martin Logan manufactured mains power supplies which deliver about 14V dc to the speakers via something like a DIN connector, rather than the normal IEC mains input I have seen on other SL3s.

I hadn't heard about such external power supplies - can anyone in the club enlighten me?

Thanks very much,

John M
Canterbury, UK

 

[jmorcom]

Update to SL3 power supply question.

Well, they sounded fine so I bought them to use as the rear pair of a quad system with my existing pair of SL3's at the front.

Both external power supplies are wall warts. One is badged as a Martin Logan unit (part number T141A9800-A6/2) the other is a generic unit.

Does anyone have a view as to whether it would be better to replace these and whatever is inside with a "standard" IEC mains input and internal HV supply board or stay with the wall warts?

Any feedback would be appreciated.

John

 

[kcl]

:welcome:
Congratulations on your new speakers! Others can give you better input than I on changing the PS out. However, unless the SL3s are different that the other Logans (which may be true as I don't know them) the power supply's use is to 'charge up' the stators to a level that can be used. Heck, once charged up you can even unplug a Logan and it'll still play for quite a while, I don't think that a 'more pure' power supply will make much difference as its really not 'driving' the speakers per se. So, FWIW I say save yourself some time, money, and trouble and leave them the way they are. You'll probably be quite happy with them.

 

[jmorcom]

Hi Ken,

Thanks very much for the feedback - I was worried that the wall warts were non-standard and perhaps may not have delivered the correct level of high voltage.

However, judging by the lovely sound I think they must be OK.

All the best,

John

 

[alekz]

Probably, the previous owner bought the speakers in the US, and replaced the PS'es to match the local voltage. Good idea BTW... I was also thinking about that, but my "solution" was external 230 -> 110 adapter. Since passive ML's practically do not consume current, even cheap transformers should work well.

I wonder if it's possible to change the ML "voltage" internally, like in the Pass Labs amplifiers. Something like a jumper.

 

[jmorcom]

I think you're probably right about the speakers originating in the US and a previous owner chaning the external power supply. What confused me was that I'd never seen an SL3 with an external supply before - they'd always had the standard IEC mains input.

I don't know whether you could change the internal wiring to change from 110Vac to 220/240V ac - that's probably a question for ML?