2 Channel Amp with Subwoofer output

[joshleb]

Evening all.

Trying to sort out my office/ home dj setup and got some old Mordaunt Short speakers and an active Yamaha subwoofer going spare so was going set these up.

Currently running it off an old AV receiver I have, but looking at changing to a mini-amp type unit as the AV just takes up too much space.

Does anyone have any recommendations? All it needs is the one RCA input, and output for two speakers and the sub.

Only thing I've been able to find so far is this ONE, anything any cheaper people know of? I don't need loud volumes as it's just a box room.

The sub has the LFE input, is there anyway I could connect it with speaker wire instead?

Thanks!

[Lucid_AV]

There are Speaker-Level-to-Line-Level convertors used a lot in the car audio game that might work for you. Here's an example.

The results with these can be a bit mixed: Some report that they work okay, whilst others complain of noise and flabby bass. You're going to have to suck it and see.

The only major caveat here is that the RCA output is stereo rather than mono. If the sub has stereo in then this won't be an issue. But if you need then to convert stereo to mono successfully without shorting out the left/right connections because you used a Y splitter in reverse then the cost is going to jump up considerably. You'll need something that isolates the L and R channels in a way that can be summed without screwing it up for the speaker outputs.

TBH, by the time you've bought the extra boxes and buggered around trying to cure any his or distortion then you might as well have bought the £85 T-amp because it's both cheaper and does the job better.

[StescoG66]

As long as there are pre amp outs then it can be made to work easily

[Tony1963]

OP,

I really can’t see you finding anything suitable for less than the £85 for that Nobsound amp you’ve linked to. That really is cheap.

[joshleb]

I ended up getting it and setting it up last night. It packs a bit more punch than I was expecting!

Would be good to test it out properly next summer when I have a garden party, but for now it's just my office music player and got the RCA plugged into some DJ decks for when I want to muck about with them.

[Crackie]

joshleb said:

I ended up getting it and setting it up last night. It packs a bit more punch than I was expecting!

Would be good to test it out properly next summer when I have a garden party, but for now it's just my office music player and got the RCA plugged into some DJ decks for when I want to muck about with them.

Class D chips can sound stunning if the company using them know how to get the best from them and in particular use high quality coils in the output circuit. Douk Audio / Nobsound do know what they are doing.

One point worth noting is that the power supply that came with your amp is a 32V / 5A unit i.e. It supplies 160W total or 80 watts per channel. You sound like you're pretty happy with the punch and drive from the amp with that 160W supply but if you wanted it to, the amp can deliver much more. The TDA7498E chip can deliver 160Watts per channel when fed with a stronger power supply; the chip is rated for 36V power supplies and can safely deliver 160Watts per channel.

Here's the data sheet for the chip https://www.st.com/resource/en/datasheet/tda7498e....

Here's a link to a suitable higher output 350W power supply https://cpc.farnell.com/tiger-power-supplies/tgr35...

Edited by Crackie on Sunday 10th October 13:38

[joshleb]

Nice one, cheers!

I've only tested it in my office which is the box room so I think anything would sound loud in there so will bare this in mind for the future!

[Crackie]

joshleb said:

Nice one, cheers!

I've only tested it in my office which is the box room so I think anything would sound loud in there so will bare this in mind for the future!

Figures 4 and 5 on the data sheet give a good feel for what the chip is capable of..........it does deliver 160w with that bigger supply but the graphs show that distortion increases rapidly at the above 100W. It's likely to benefit a lot from that beefier power supply but you can see that total harmonic distortion is 0.04% in the 10 to 20W region and stays under 1% at powers below 125W but shoots up to 10% at 160W.

[WyrleyD]

I was looking at this amp to power my Monitor Audio floor standers, in the Q/A someone asked about connecting a turntable and they advised purchasing a Tube T1 as a power amp for the MM turntable which then plugs into the Nobo amp

Does this make sense?

[Tony1963]

WyrleyD said:

I was looking at this amp to power my Monitor Audio floor standers, in the Q/A someone asked about connecting a turntable and they advised purchasing a Tube T1 as a power amp for the MM turntable which then plugs into the Nobo amp

Does this make sense?

No, that’s a pre amp, and it has no phone stage (phono stage amplifies the tiny output from a turntable cartridge up to something a pre amp can use).

This is better for that: https://www.amazon.co.uk/dp/B07QBXV3CG/ref=cm_sw_r...