Help needed! finding AC-AC adapter?

[jozz]

For a deprecated, but handy, pre-amp I need a 17V 500mA AC to AC adapter.

Specifically this one:

https://www.amazon.com/UpBright-Adapter-Replacement-4-Channel-SMP-QPRE-1/dp/B01C8BKFF8

If I order this one, shipping and handling will accumulate to a total cost of over €52 euros, way more than the economic value of this pre-amp.

I have searched the web for some time now, but the exact thing I need doesn't seem there.

Is there anybody who can find a 'ac to ac adapter 17v 500mA' pref. with that typical cylindrical 9v connector (I prefer not to solder anything on).

 

[JeffJetton]

Isn't that an AC to DC adapter? So, for example: https://www.amazon.nl/17V-1A-AC-DC-adapter/dp/B0BP6YHGQD

(Not sure if the connector is the right size though.)

I'd imagine you could higher in amps with little trouble. As long as you have at least 500mA.

 

[Ventura]

some MI equipment use ac to ac adapters, and provide
the rectification internally

Alesis sound and FX modules, Yamaha (small, unpowered) portable Mixers
some Mackie mixers. Several models of HP printers and many of the
old Westfell and other line models (when DSL was coming into use)

and some lighting FX use AC only as the motor timing/speed is
controlled by the AC frequency

so if one has access to q box of old wall-warts at a nearby
music go round or similar, sometimes you can find something near
enough in voltage

 

[JKJ]

Sounds like you could use a simple step-down transformer like this one from McMaster Carr:

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

A step-down transformer simply converts a higher voltage AC to a lower voltage AC.

It has three different output taps, including one at 16 volts.
I strongly suspect there is some electronic supply house in your area that sells a similar device. I’ve even salvaged similar transformers them from old equipment.

BUT, these are not “plug-and-play” - you would need an enclosure, an power cord, an AC voltmeter (to confirm the voltage), output wires in a protective cable, and the proper end to plug into your equipment. Some mounting, soldering, and testing would be required. All this is trivial for someone who knows how - if unfamiliar, there is certainly someone near you who could do it, probably for free. The problem might be finding them. Know any electronic geeks, maker’s clubs, tinkerers, electronic repair people or shops?

JKJ

 

[Glug]

Just a thought but if the pre-amp needs 17v AC and internally rectifies it couldn't you just give it 17V DC ?
Presumably half of the rectification diodes might get slightly warmer but it should still work.
It's fairly unlikey there's a transformer inside the pre-amp.

 

[Snoopz]

Just a thought but if the pre-amp needs 17v AC and internally rectifies it couldn't you just give it 17V DC ?
Presumably half of the rectification diodes might get slightly warmer but it should still work.
It's fairly unlikey there's a transformer inside the pre-amp.

The preamp likely uses older +-15V Opamps, making the use of 17VAC the correct choice due to the rectification losses. No further transformation needed.

 

[Glug]

The preamp likely uses older +-15V Opamps, making the use of 17VAC the correct choice due to the rectification losses. No further transformation needed.

Doh, now I remember - things used to use + and - rails.
That does explain the AC power input.

 

[JerryPH]

I found one here for under $20US:

https://www.amazon.com/Onerbl-Adapter-Replacement-4-Channel-SMP-QPRE-1/dp/B0CS674912

 

[jozz]

I found one here for under $20US:

https://www.amazon.com/Onerbl-Adapter-Replacement-4-Channel-SMP-QPRE-1/dp/B0CS674912

sadly

(and, not ideal: it would need a US->EUR socket convertor)

 

[Snoopz]

https://amzn.eu/d/hStm6C6

here's one from the German Amazon site, maybe they'll deliver to you? It does have a peculiar connector though. There are a lot of similar models with only 420mA power output.

 

[PhiliGol]

Hi Jozz
Maybe this is what you're looking for:
Power-supply Thorens/Pro-Ject
Small, affordable, just right voltage/current-rating.
Also gives you a hint in case you don't like this particular one: many record-players used this type of power supply.

 

[debra]

https://amzn.eu/d/hStm6C6

here's one from the German Amazon site, maybe they'll deliver to you? It does have a peculiar connector though. There are a lot of similar models with only 420mA power output.

Substitute something in the URL and you get https://www.amazon.nl/dp/B09RJS2FJ5?ref_=cm_sw_r_cp_ud_dp_7GTCQ8W7QNPMJ2NAEFNN
which is still €39,62 but better than €50 and no customs or other duties to consider.

 

[jozz]

Hi Jozz
Maybe this is what you're looking for:
Power-supply Thorens/Pro-Ject
Small, affordable, just right voltage/current-rating.
Also gives you a hint in case you don't like this particular one: many record-players used this type of power supply.

looks good to me, may be even a direct replacement without tinkering
thanks man!

i guess the magic word was 'transformator'

 

[PhiliGol]

i guess the magic word was 'transformator'

Yes, power-supplies today mainly come as a switched-mode AC/DC-converter.

 

[jozz]

Yes, power-supplies today mainly come as a switched-mode AC/DC-converter.

it arrived today from Germany

works like a charm including 48v and hiss free - the blue light of success!

thanks again!!