Replace old distribution amp

milleniumaire

Active Member
My in-laws have recently had Sky+ installed and I want to help them distribute it to other TV's in the house. Attached is a (poor quality) photo of their existing amp in the loft and I have numbered the cables.

The aerial is installed in the loft and the coax cable running from it (cable 1 in the photo) connects to a Wolseley TV systems mast head amplifier, then runs on passed the distribution amp shown in the photo. It doesn't connect to the distribution amp, but I assume continues down to the viewing room.

The Antiference Power Unit (PU 1) shown in the photo to the right of the Antiference 4-outlet amplifier (UP2504) is what I assume is providing power to the masthead amp.

I assume that cable 3 is from the viewing room and connects to the IN UHF connection on the amp. I'm not sure where cable 2 comes from (brown cable behind others in the picture, but this is connected to the IN FM socket on the amp). Cables 4, 5 and 6 are connected to sockets labelled 1, 2 and 3 on the amp. As can be seen in the photo, cable 7 is from socket 4, also labelled as 12v and goes to the PU into the IN socket. The OUT socket on the PU runs to the old aerial outside. I can't remember if there is an aerial outside still, I suspect not as this might cause problems with two aerial feeds! (I'm not at the house at the moment so can't check).

My plan is to replace the amplifier with a Philex SLx 6 way distributor, however, I'm not sure which model to choose:

6-way Aerial distribution amplifier F-plug - Standard Amplifiers - Products - Philex (27823F)

6-way Satellite distribution amplifier F-plug - Standard Amplifiers - Products - Philex (Gold)

I'm not sure if I should go for the gold version or the (older?) 27823F model, whichever I choose I've decided to go for the version with the F connectors.

The older model gives upto 12 dB gain per split and includes 25mA line powering for masthead amps, which makes me think I could then remove the existing power supply for the masthead amp, to free up the power socket for the new amp (the existing amp doesn't require power).

If I went with the gold version (which I don't believe includes 25mA line powering) and gives only 8 dB gain per split then I guess I would need to connect the masthead power supply to one of the spare connectors on the amp to ensure power is provided. I assume I could simply use cable 7 to do this and the new amp connector doesn't have to allow for 12v (as the old amp connector appears to suggest). I would also need to use a power adapter to enable both the existing masthead amp PU and the new amp to plug into the single socket.

In either case I would stick with the mast head amp to boost the signal down to the viewing room, then into the sky box and out through UHF2 back up to the UHF input on the SLx. As far as I can see both amps would be cabled in the same way, apart from the extra cable required for the masthead amp PU on the SLx Gold, assuming the 25mA line power provided by the 27823F model does power the old Wolseley TV systems masthead amp.

I would appreciate confirmation/advice on my suggested approach.
 

Attachments

  • Existing.jpg
    Existing.jpg
    145.9 KB · Views: 495

Stevenage Neil

Distinguished Member
I'm sorry but your explanation of the wiring doesn't make sense to my simple mind. Perhaps if you took a photo of the label on the distribution amp it may be clearer.

PS This isn't really a HD topic is it?
 

logiciel

Moderator
There are a few odd details about which cable does what, and I can't find a UP2504 -do you have more details of that - labelling, etc?
 

logiciel

Moderator
It's certainly the same house, at least!
Your post and mine say and ask much the same, but what forum it ought to be I'm not totally certain....
 

Johnbyte

Active Member
Looks like an update to the OP's earlier post.

The bit I don't understand is where the Wolsely masthead amp connected to the loft aerial is getting its power feed from (was this amp originally connected to the roof aerial?). The output, (i.e. the 6/12v) from the PSU is connected via cable 8 to the old roof aerial, if it's still there, but nowhere near the masthead amp. If the loft aerial is connected to the masthead amp, it should be getting its power feed via cable 1. Are you certain the masthead amp is actually doing anything?

Also the IN socket on the PSU is connected to an output on the distribution amp and therefore doesn't appear to be doing anything (in its normal implementation the IN socket would be connected to the TV).

As for the replacement distribution amp, I'd be looking at either Labgear or Antiference rather than Philex
 

Stevenage Neil

Distinguished Member
Seeing as the "Old" aerial goes into the "PSU" I doubt it is a"PSU" at all - just a UHF amplifier.
 

Johnbyte

Active Member
Seeing as the "Old" aerial goes into the "PSU" I doubt it is a"PSU" at all - just a UHF amplifier.

Could be. Still begs the question as to where the masthead amp is getting its power from, and why it's connected to what appears to be an output on the distribution amp.
 

Stevenage Neil

Distinguished Member
What do they say? "A little knowledge is a dangerous thing"
 

milleniumaire

Active Member
Neil, you are correct, I am the same poster as http://www.avforums.com/forums/sky-...ogue-signal-when-plugged-into-sky-hd-box.html. Having failed to determine the reason for the poor signal, I decided to bite the bullet and go ahead replacing the old equipment in the loft in the hope that this would provide a better signal and enable the tv-links to work. Unfortunately, when I looked at the way things were connected, I got a little confused and it seems I'm not the only one. I'm guessing that when my father-in-law installed the largest aerial he could find in the loft, he didn't touch the masthead power supply, but may have switched some of the cables around and got it to work (possibly trial and error!). I'm only guessing and unfortunately he did it so long ago and he's now in his late 70's that he can't remember.

I can confirm that if I unplug the Antiference Power Unit PU 1 device then none of the TV's get a signal. Also, if I unplug cable 7 (to the amp) from the IN socket I get the same thing - no signal on any of the TV's. If I unplug cable 8 from the OUT socket (going to the outside aerial, which I can confirm doesn't exist any more - the cable end is in the loft), then this makes NO difference to the signal on any TV.

Cable 7 is white, the original aerial cable 8 is brown. Cable 1, to the new aerial, is connected to another cable underneath the amp, just out of shot. I'm wondering if originally, the Antiference Power Unit PU 1 had the old aerial cable plugged into it (IN or OUT I can't say), the other cable plugged into this device then went down to the viewing room. When my father in law installed the new aerial, he cut the cable going down to the viewing room and attached the new aerial cable to it. He then added the white cable 7!

I'm unable to supply any more information for the Antiference 4-outlet amplifier, UP2504, however here is what is printed above each socket (from left to right):

IN FM
IN UHP
1
2
3
4 12V

There is another powered device downstairs behind the TV in the viewing room, so I guess it's possible this is the masthead power unit. This also has a couple of coax cables plugged in and is labelled IN and OUT. Details of how this fits in are in my earlier post.
 
Last edited:

milleniumaire

Active Member
Another thought - The amp and what I thought was the masthead amp power supply are both made by Antiference, whereas the masthead amp is a Wolseley TV systems device. As the masthead amp is connected to the cable coming from the new aerial, this may suggest it was added at the same time as the new aerial (although I can't be sure). One conclusion may be that the powered device downstairs is the power supply for the masthead amp (as these are usually installed near the TV). If this is the case I don't understand what the Antiference Power Unit PU 1 is doing or is it possible this is simply the power supply for the amplifier? But why design an amplifier that needs an additional device to provide power, rather than simply building it in and supplying a plug? Also the amp is brown and the PU 1 unit is white, which suggests they didn't come in the same box!
 

logiciel

Moderator
The nearest I can find for the Antiference is masthead amplifiers.
The PU ought to be just an aerial amplifier (S N), in from the outside aerial, out to the distributor.
What its Input is doing connected to the Antiference socket that we now know calls for 12v of power is a mystery.
Just to reduce the list of questions very slightly - isn't the Antiference's second IN connection actually UHF?
As you say, the two devices don't seem to be made for each other!
johnbyte - which "output on the distribution amp" are you referring to?
 
Last edited:

Johnbyte

Active Member
I think we can reasonably deduce that the PU is providing the supply for the Antiference distribution amp, given that it's plugged into a socket marked 12v (which I had assumed from the earlier posts, was an output). That would account for there being no distributed signal when cable 7 is unplugged. The PU must output 12v on both in and out sockets - slightly unusual. Almost certainly the powered box in the viewing room provides the supply for the Wolsely masthead amp. So all is now clear!

As to which of the replacement distribution amps would be better - it's really down to how much gain you need. Now we know the Wolsely masthead amp is powered from the living room, that's no longer a consideration. You'll still only need the one socket in the loft to power the new distribution amp.
 

logiciel

Moderator
You must be an optimist - "all is now clear".:)
It's more than "slightly unusual" imho that the "PU must output 12v on both in and out sockets", which indeed it must.
 

milleniumaire

Active Member
Thanks guys. I'm inclined to agree that I needn't worry about power for the masthead amp, however, if I went for the 27823F model, then I could not only replace the amp and it's power supply in the loft, but also remove the masthead amp power supply in the viewing room. I don't see anything that the gold version gives over the 27823F model, apart from being easier to find. I guess this may be due to it being a newer model.

Johnbyte, you recommend Labgear or Antiference rather than Philex, however, the SLx seems to have everything that is needed and is much cheaper. The Labgear and Antiference amps I've seen do look good, but they are loft boxes and therefore take the aerial + Sky feeds and send them down to the sky+ box as well as receiving the return for distribution. I don't need any of that, just the distribution function, so why pay extra? Also, I have an old SLx 6 way amp in my loft and it's been working perfectly for 12 years now.
 

Stevenage Neil

Distinguished Member
May I make a simple suggestion that you discover definitely where each of the cables goes before you do anything?
 

logiciel

Moderator
Seconded.
 

Johnbyte

Active Member
but also remove the masthead amp power supply in the viewing room.

Not sure how you would do this as the output from the masthead amp currently bypasses the distribution amp. You'd need to connect it somehow as a second input, the main input being the return feed from the viewing room.

The Labgear and Antiference amps I've seen do look good, but they are loft boxes

They both do a wide range of distribution amps as well as loft boxes (which I agree you don't need). Ultimately it's a matter of personal choice....
 

milleniumaire

Active Member
Following the route of the cables is easier said than done. They disappear into the Walls so I can only guess where they are going based on their direction.
 

Stevenage Neil

Distinguished Member
How many rooms have an aerial point?
How many cables go into the amp?
 

milleniumaire

Active Member
Johnbyte I see what you mean about getting power from the distribution amp to the masthead amp. I take it the return feed from Uhf2 on the sky box is no good as the sky box would remove the current from the coax cable.
 

milleniumaire

Active Member
There are Tvs in 6 rooms. The viewing room has 3 aerial points (see my previos post for details). One other room has 2 points but only one is used. All other rooms have 1 point. The photo shows all the cables connecting to the distribution amp.
 

Stevenage Neil

Distinguished Member
If you have signal to all the TV's then just remove one cable at a time from the distributor and determine where you lose signal.
 

Stevenage Neil

Distinguished Member
..That would account for there being no distributed signal when cable 7 is unplugged.

Just had another thought on this: Perhaps the old aerial is being used for TV reception. As I said earlier, what is being called a PSU looks mighty like a UHF amp. It may also supply power to the distributor.
To prove it, leave cable 7 connected and disconnect the old aerial lead.
Perhaps the new aerial is an FM one?

Another thought: Cable 8 might go to one of the rooms.............probably the furthest one.
 
Last edited:

The latest video from AVForums

Star Wars Andor, Woman King, more Star Trek 4K, Rings of Power & the latest TV, movies & 4K releases
Subscribe to our YouTube channel

Latest News

Starzplay streaming service rebrands as Lionsgate+
  • By Andy Bassett
  • Published
JVC adds Filmmaker Mode to latest D-ILA projector firmware
  • By Andy Bassett
  • Published
Bowers & Wilkins launches Px8 headphone
  • By Andy Bassett
  • Published
Sky set to launch its plug-and-play Sky Stream solution
  • By Ian Collen
  • Published
Movies Podcast: 26th September 2022
  • By Phil Hinton
  • Published

Full fat HDMI teeshirts

Support AVForums with Patreon

Top Bottom