RCA switching input

[Martin Bush]

Hi all

I have a nice old Sony receiver amplifier which has only one line level RCA input. This is actually the tape input.

I currently have a four-way switching box attached which allows me to go between a few sources. I got this off the market second hand - a stroke of luck.

However I will soon want to add more sources to the amp. The line up will be:

Cassette deck
Mini Disc Deck
CD
8- track cartridge player
Computer audio
Record deck (this is a Garrard which appears to have a built in phono amp)

So that's at least six sources and I am sure another one will come along soon enough.

I know that recording presents its own challenge as I have two recording formats on that list, but for now I would like to know if anyone knows of any decent yet cheap 6-input selectors I could use?

I have found some on ebay but the 6-way ones incorporate a volume control and I've no idea why I'd need one of those. The inclusion of the volume pot makes me wonder whether it's a gimmick that will degrade the sound. All I really want is a simple six or more selector.

Anyone know where I might get one?

Of course I could get a different amp, but that would require further expense and I quite like my 1980s Sony, even if it has some buttons missing

Martin

[Kala_12]

Hi Martin,
Could you not make one yourself? Or get the six way unit off 'the market' and remove the volume pot?
Stuart.

[Martin Bush]

Hiya

I could make one myself although I am not sure of the best approach, but am happy if someone could suggest a circuit. I can easily find enough RCA sockets but I'm not sure what switch would work best and how to ensure I don't create grounding issues. The one I have does have a slight buzz to it sometimes when you move the selector switch.

By "the market", I literally mean Oxford outdoor flea market. The current box was about £2 from a house clearance stall and has been very useful. And yes, I guess I could simply remove the vol pot from the ebay ones I mentioned. That's not a bad idea - I do wonder why there's the control there in the first place.

Martin

[Edward Huggins]

You say your Garrard record deck has a built in pre-amp? That would be unusual - what type is it? Be aware also that the more interconnects you have will add some insertion loss and maybe add hum.

[bikerhifinut]

Hi Martin,
I will assume you have an idea for a case? ideally a metal one and then you need not worry about the faff of screened cables inside your switching box.
Bear in mind Edwards advice about switching losses. At line level it's negligible but keep the connecting lead from the out put of the box to amp as short as possible.
You say you have plenty of RCA sockets, so I shan't make any suggestions there.
Ok so all you need is a switch, a metal box for preference, and some wire, any decent and not too thick for ease of handling stranded wire will be good. You can use solid core at the expense of a bit of flexibility when building it but the sound quality won't be affected. IMHO.
So to the switch,
This will be perfect its a standard 6way 2pole job and versions are available universally. And before any comments on quality etc etc, I use the identical style in some pretty high falutin gear that I built again IMHO, i would say that wouldn't I!
https://www.cricklewoodelectronics.c...ry-Switch.html
Wiring it up is simple.
Take the output from the wiper and connect each input "hot" to the corresponding tags on the outside of the switch.
Run the earth returns together along the back of the sockets and across to the output socket earth return.
OR save yourself a pair of output sockets and fit a flying lead with RCA plugs to the output which saves a set of contacts.
Drop me a PM Martin if you want a natter about it.
Its an issue with earlier amps made in the days when disc radio and tape were the only sources of note!
You shouldn't have any hum issues if it's wired up properly and the cable screening is adequate. This is line level so noise is less of an issue.

Andy

[Stuart R]

Martin,

It might be worth checking out some of the lesser known brands of A/V industry switchers. Now everyone's going HDMI and Digital Video with embedded audio, there may be some analogue bargains to be had.

Kind Regards,

SR

[Martin Bush]

Originally Posted by Edward Huggins

You say your Garrard record deck has a built in pre-amp? That would be unusual - what type is it?

Hi Edward

I will take a proper look when I have some time. I say it has a built in preamp simply because when trying it out I was able to get a good sound simply by plugging into the amp (ie not via the phono input).

I may be talking complete rot now I think about it.

The deck is packed up as we are moving house, but I believe it was from a system and has the number 4 on the perpex lid.

Having said all that, I also have a phono amp spare so could use that if needs be.

Martin

[Martin Bush]

Update...

The record deck is branded Unit Four.

Martin

[bikerhifinut]

Someones going to know the system it was in.
Have you examined the cartridge Martin, it may be a ceramic in which case you will get an acceptable output into a decently high input resistance at line level. By the sound of your amp it dates from a time when line sensitivity would be around 100 to 200 mV.

A.

[Edward Huggins]

No, that's not the type of record deck, that's the name on the plinth/lid. What type of cartridge is fitted? It suspect it may be a Garrard deck fitted with a crystal or ceramic cartridge. That's why you think it already has an in-built pre-amplifier, because it already gives a high output. There's unlikely to be any pre-amp as such cartridges do not need one.

[Martin Bush]

Hi Edward

The deck is a Garrard SP25 as far as I know. I just meant that it was branded Unit Four, which I think was a Marconi system, and thought that might be helpful information. It's packed away for a house move so I was only able to get at one corner.

That's a side issue really as my main concern at the moment is achieving enough inputs. Thanks to members I think I have some good avenues to follow to achieve that.

Martin

[PaulR]

What about something like this https://www.ebay.co.uk/itm/254925636...YaAhW_EALw_wcB

Or this https://www.amazon.co.uk/QiCheng-LYS...a-905411945490

[usradcoll1]

Originally Posted by Stuart R

Martin,

It might be worth checking out some of the lesser known brands of A/V industry switchers. Now everyone's going HDMI and Digital Video with embedded audio, there may be some analogue bargains to be had.

Kind Regards,

SR

Hit the charity shops!
I bought a few analogue switchers with left, right audio and video jacks, four sets of inputs and one output. It seems to work alright. Just disregard the video jacks.
Dave, USradcoll1.