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Andy831
17th October 2009, 07:28
I have now had my Quad 33 / 303 fully serviced and it sounds magnificent and will probably sound even better when its fully run in. I still have my Glasshouse which I also really like and enjoy, however they tend to major on different kinds of music and dependant on my own mood how I am feeling. If I want a bit of balls out R & R at high volume then its the Quad all the way, if I want a bit of a relax with a lady singer and some gentle acoustic playing its the Glasshouse every day.

Due to the size of my speakers and the relatively small listening room add to that the problem of where the kit is housed, its a bloody pain to change the speaker cables from one amp to the other, so it occured to me why not buy or build some kind of switch box. that allows two amps to be connected to it, but feeds into 1 pair of speakers only. I realize that there are technical difficulties with this arrangement and the possibilty that you could have two amps live into one pair of speakers. However as I am the only user of the system, I am happy in my own mind that the switch would only be operated when both amps are switched off.

Does anyone know who manufactures such a switch, or could even possibly attempt to draw me a circuit diagram that will allow me to attempt to build such a switch.

Thanks in advance

Andy

Paramaribo
17th October 2009, 09:37
Hi Andy, I have such an item almost ready, and it should be on sale in the next six weeks. It has taken some time to develop, and I am now working on the printing for the front panel. I got bogged down by another product of mine called the Caiman...

Send me a PM and I'll discuss delivery with you further. I might be able to get you one ahead of anyone else:).

Stan

DaveK
17th October 2009, 11:49
Hi Guys,
I have a similar(ish) problem that I would appreciate your comments on.
I have a hi-fi(ish) amp and an AV amp and would like to use the hi-fi speakers as front L & R speakers fed from the AV amp. In my naivete I thought about just having 2 sets of speaker cables feeding each speaker, (1 set from each amp), permanently bare wired into the speaker screw terminals.
Put another way, similar to Andy831 above but without the extra complication of a switch.
Apart from the obvious potential problem of what would happen if I were absent minded enough to leave both amps feeding the speakers at the same time (what would happen, just out of interest?), are there any other reasons why I shouldn't do this?
Thanks in anticipation of any responses, and apologies to Andy831 for complicating his original thread but I thought that my problem was so similar to your's that they could 'run' together. If the answers are not similar I'll peel my question off and start my own thread :) .

Andy831
17th October 2009, 12:10
No problem Dave

I see this as an opportunity for some enterprising chap who could develop such a switch as its the sort of thing I would see being useful to virtually ever Audiophool I know, I mean come on hands up anyone on any of the forums that does not have at least two amps LOL

DaveK
17th October 2009, 12:22
No problem Dave

I see this as an opportunity for some enterprising chap who could develop such a switch LOL

That enterprising chap is our own Paramaribo (aka Stan the Man) - see his post above :) .
Hi Stan, I guess the fact that you see a niche for a speaker switch indicates that 2 feeds to 1 pair of speakers is not a good idea - can you explain (simply) why,please? It looks as though I could be in the market for one of your new switches. (PS hope you are picking up a bit, flu wise :) ).

Andy831
17th October 2009, 12:43
I see the problem being if you inadvertantly send power from both amps you could blow the speaker and or the amps, assuming that can be overcome then assuming one amp is a valve amp, the other problem would be switching the valve amp on unconnected to a load which may again blow the amp. Although remember I am seriously non techie so I might be talking complete bollocks:confuzed:

Andy

Andy831
17th October 2009, 12:46
Looks like they are available, however the quality does not look too good

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=120480969371

Chops54
17th October 2009, 12:51
You need to be careful when switching speakers or amps, especially you Andy having both valve and solid state amps. Valve amps don't like being run without a load on the output transformer and solid state don't like having their outputs shorted. Unless there's something built into the switching unit to prevent either of these situations occuring, you need to make sure both amps are switched off before changing over. I know this sounds simple but it's easily overlooked.

woody
17th October 2009, 13:35
would it not be easier to buy another set of speakers :hiding:

DaveK
17th October 2009, 14:45
would it not be easier to buy another set of speakers :hiding:

Now why didn't we think of that? :D :D :D
Probably (for me, anyway) 'cos speakers ain't cheap, and also the WAF of another pair of (expensive) speakers in the lounge would descend well into sub-zero territory, as would the home atmosphere!! :D :D :D

Andy831
17th October 2009, 17:06
would it not be easier to buy another set of speakers :hiding:

Why would I want more speakers I own 15" Tannoys :wink:

Andy831
17th October 2009, 17:12
You need to be careful when switching speakers or amps, especially you Andy having both valve and solid state amps. Valve amps don't like being run without a load on the output transformer and solid state don't like having their outputs shorted. Unless there's something built into the switching unit to prevent either of these situations occuring, you need to make sure both amps are switched off before changing over. I know this sounds simple but it's easily overlooked.

I realize there are downsides to the proposal Si and I did indeed flag up that as a potential problem in my original post.

I never see a time when I would want to switch amp mid session so I don`t think it would be an issue for me and Anita does not use the system so no problem there.

I have found a site that sells a suitable box that will allow you to connect 6 different amps to 1 set of speakers, but again the connectors are cheap and nasty spring loaded things, I wanted Phonos and Banana sockets. I suppose I could buy one of these and rebox / add new connectors

http://www.ambery.com/6stspseamsws.html

Andy831
17th October 2009, 17:24
I am quite Keen now to see what Paramaribo has to offer us. :cheers:

Chops54
17th October 2009, 17:37
Andy, do you remember the good old days when Lasky's in Preston had a speaker comparator that could switch about twenty sets of speakers?

Yes, I know what you're saying in that you wouldn't change amps on the fly but it's easy to leave equipment switched on without realising, like I forgot to tighten the headshell in my enthusiasm to get an lp on the go.
If you look at that drawing in the link you posted, it's evident that the maker assumes we all use SS amps.
Speaker switching in my opinion isn't good for the sound either.
If you don't intend to change amps on the fly, then run two sets of cables, one set to each amp and fit them with shrouded plugs. Plug in either set according to which amp you wish to use. I've seen some banana plugs with spring loaded outer sleeves that shield the pin when not in use.

woody
17th October 2009, 18:40
Why would I want more speakers I own 15" Tannoys

2 pair how good would that be :dude:

Paramaribo
17th October 2009, 18:59
My unit is not designed to be switched over whilst the amps are powered up. That would require extra circuitry within the signal path. And that could bugger up the sound.

http://www.beresford.me/images/connectors/TC-722.jpg
(http://www.beresford.me/images/connectors/TC-722.jpg)

Chops54
17th October 2009, 19:08
My unit is not designed to be switched over whilst the amps are powered up. That would require extra circuitry within the signal path. And that could bugger up the sound.

http://www.beresford.me/images/connectors/TC-722.jpg
(http://www.beresford.me/images/connectors/TC-722.jpg)


That looks very good Stan :^

Paramaribo
17th October 2009, 19:16
The product number is TC-722, but I was looking for a suitable name as well. What about the Crossover Network:D?

DaveK
17th October 2009, 20:43
If you don't intend to change amps on the fly, then run two sets of cables, one set to each amp and fit them with shrouded plugs. Plug in either set according to which amp you wish to use. I've seen some banana plugs with spring loaded outer sleeves that shield the pin when not in use.

Hi Chopsaw,
At the moment (pending Stan's Crossover Network ;) ), I favour your response above. It also helps that I've got a second set of speaker cables that I've just swapped out. Until now both ends of my speaker cable connections have been bare wired on the basis that introducing solder into the mix is giving one more metal-to-metal interface at each end which, IMO, is best avoided if possible.
However, if I am going to adopt your above solution, I can see the benefits of using banana plugs with spring loaded covers, at least at the speaker end - can you give me a pointer as to where they can be bought please?
Thanks in anticipation,

cartridgemangler
17th October 2009, 22:39
Hi Guys,
I have a similar(ish) problem that I would appreciate your comments on.
I have a hi-fi(ish) amp and an AV amp and would like to use the hi-fi speakers as front L & R speakers fed from the AV amp. In my naivete I thought about just having 2 sets of speaker cables feeding each speaker, (1 set from each amp), permanently bare wired into the speaker screw terminals.
Put another way, similar to Andy831 above but without the extra complication of a switch.
Apart from the obvious potential problem of what would happen if I were absent minded enough to leave both amps feeding the speakers at the same time (what would happen, just out of interest?), are there any other reasons why I shouldn't do this?
Thanks in anticipation of any responses, and apologies to Andy831 for complicating his original thread but I thought that my problem was so similar to your's that they could 'run' together. If the answers are not similar I'll peel my question off and start my own thread :) .

For a start, you'd probably blow the output of at least one or both of the amps.
second, if you have one amp switched off, the other amp is going to see the second set of cables and the output of the other amp in parallel with your speakers. part of the current from your output will try to flow through the circuitry of the powered-down amplifier's output stage, causing lower power getting to the speakers, and probably blowing the output of the amp that is off, causing the amp that is powered up to have to work harder, and probably blowing that as well.

It's not a good idea in short. (pun intended)

ESK
17th October 2009, 23:02
It's not a good idea in short. (pun intended)

Boom! Boom!

http://1.bp.blogspot.com/_Qm2i8mXTjhs/SiTvZiiAAPI/AAAAAAAABfE/ntifAqFspJ0/s400/basil+brush.jpg

DaveK
17th October 2009, 23:33
Hi Kenny,
Thanks for your detailed response - just what I like - short, blunt and to the point - are you sure you're not a Yorkshire man ;).
To avoid my own short response (pun intended :) ), I shall abandon my idea and follow Chopsaw's advice re 2 sets of speaker cables each ending in shrouded banana plugs (preferably non-solder type) if I can find a source.
Thanks again.

Andy831
18th October 2009, 06:10
My unit is not designed to be switched over whilst the amps are powered up. That would require extra circuitry within the signal path. And that could bugger up the sound.

http://www.beresford.me/images/connectors/TC-722.jpg
(http://www.beresford.me/images/connectors/TC-722.jpg)

Stan that looks very good, I have sent you a Pm

Andy

Chops54
18th October 2009, 10:18
If you're bothered about solder joints then a switch box isn't for you Andy.

Andy831
18th October 2009, 11:08
No too worried about soldered joints Si, funnily enough there are quite a lot of soldered joints already in my amp:D

I got Johns new Rega weight here now if you fancy a trip across for a couple of hours listening and evaluating.

Andy

Chops54
18th October 2009, 11:57
No too worried about soldered joints Si, funnily enough there are quite a lot of soldered joints already in my amp:D

I got Johns new Rega weight here now if you fancy a trip across for a couple of hours listening and evaluating.

Andy


So why are you bothered about solder in banana plugs?

Chops54
18th October 2009, 11:59
Andy, I'd love to come over. I have a job to look at in half an hour so I can nip over after that if that's ok.

Andy831
18th October 2009, 14:05
Sorry Si

I cant do today, I have only just seen your last post and I am out all day from now.

I have this weight for sixty days starting last Friday so we have plenty of time we could do it next week or the week after to suit you.

Andy

Ps I think your getting your posters mixed up, I think it was Davek who had concerns about soldered banana plugs not me LOL

Chops54
18th October 2009, 14:16
Hey, no problem Andy, that's better for me.Give us a shout whenever.

Yes it was DaveKs post. Don't know why I thought it was yours LOL. You must've been wondering what I was rabbiting on about:eek:

I've just been to see that bloke and he wants a new bungalow wiring from scratch with a fancy kitchen, smoke alarms, burgular alarm etc and a cert at the end. I offered him a cheap job at 1500 quid and he shit himself. He offered me 100 quid a day LOL.

Paramaribo
18th October 2009, 16:08
I've just been to see that bloke and he wants a new bungalow wiring from scratch with a fancy kitchen, smoke alarms, burgular alarm etc and a cert at the end. I offered him a cheap job at 1500 quid and he shit himself. He offered me 100 quid a day LOL.
Out of interests, how many days would it take to do the job? What would you consider a fair hourly rate?

Chops54
18th October 2009, 16:49
Out of interests, how many days would it take to do the job? What would you consider a fair hourly rate?

Around five days Stan. I don't work for an hourly rate, I quote for the job. I make profit on my materials etc. If I was going to charge an hourly rate I may as well just go back to work for someone else.

I would consider 25 quid an hour a fair rate for a JIB approved spark working for himself.

Paramaribo
18th October 2009, 17:32
The estimate of 1500 is close. At 25 per hour over 5 days is 1000. Certification is always extra. I have a mate who charges 250 for that.
Material etc is also always extra. My mate gives the customer the option to buy the material themselves based on a supplied list. He adds traveling expense, phone calls, etc. if he needs to get the material just in case a customer starts arguing that an item is only 10 in the shop, but he bills for 15.

100 a day is not bad for someone who is an assistant. But if you have to manage and plan the job then 25 an hour is too cheap.

I was also a qualified electrician by the way, but I gave that up to study engineering. I thought the pay would be better, but I was well wrong.

Andy831
18th October 2009, 20:59
I've just been to see that bloke and he wants a new bungalow wiring from scratch with a fancy kitchen, smoke alarms, burgular alarm etc and a cert at the end. I offered him a cheap job at 1500 quid and he shit himself. He offered me 100 quid a day LOL.

I reckon 1500 is a bloody fair price Si

But given my recent experiences with pricing up work, I am afraid his reaction was a sign of the times, and I have certainly had to start reducing my rates to ensure I secure work.

Andy

Chops54
18th October 2009, 21:48
Stan and Andy,

Your views are appreciated and yes it's a sign of the times as you say Andy when punters want more for less. Stan, when I buy my gear for the job I get it at trade and I know where to go for good gear at the right money and even after my markup I'm still usually cheaper than the customer can buy it. I'm not vat registered either so they save a bundle on labour as well, yet quite a few think you're having them over. Maybe that's because they're dodgy themselves eh?

Me and a mate have teamed up during these difficult times to pool our resources. We've just had an installation accepted for a fancy kitchen at two grand. We're subbing for another company and they've told us they can't come anywhere near our price. We could actually do it for much less but if the money's there.....

We can work for less because we don't have fancy offices or a QS strutting around on 35 grand and I run around in an old Defender. This company we're subbing for has to charge 40 quid an hour per man to make a profit. With hard times ahead I think we'll pick up some decent work.

Andy831
19th November 2009, 08:57
Hi Stan

Any sign of the switch box?

Paramaribo
19th November 2009, 11:46
Almost there. I worked with a jack manufacturer to make a more exclusive banana socket, and the new part should be with me later this month. We can then roll the production and have stock next month.http://www.beresfor.me/images/TC-7220/jack.jpghttp://www.beresford.me/images/TC-7220/jack.jpg
http://www.beresford.me/images/TC-72220/jack.jpg

DaveK
19th November 2009, 11:54
Hi Stan,
Stock next month?? ooooh, great :) - please put my name on one if you will - please accept this as a pre-order.
No. 1 on the list again, eh?
Cheers,
Dave.

Andy831
19th November 2009, 12:53
Hi Stan,
Stock next month?? ooooh, great :) - please put my name on one if you will - please accept this as a pre-order.
No. 1 on the list again, eh?
Cheers,
Dave.

Hmmm

Looking Good Stan

Sorry to Piss on your chips Dave but your ALREADY second in line :D (Probably better to get the Beta test model No 1 out of the way anyway)

Andy

DaveK
19th November 2009, 13:11
Hmmm

Looking Good Stan

Sorry to Piss on your chips Dave but your ALREADY second in line :D Andy

Hi Andy,
I have no wish to spoil your day or embarras Stan by telling you of the 'Special Relationship' that we have, ;) , so you carry on with your self delusion, Stan and I know the truth, so there!!
Seriously though, as long as I get one of the first shipment batch I am perfectly happy.
Cheers,
Dave.

j7
19th November 2009, 22:54
looking good stan!!

Andrew
20th November 2009, 21:30
You need to be careful when switching speakers or amps, especially you Andy having both valve and solid state amps. Valve amps don't like being run without a load on the output transformer and solid state don't like having their outputs shorted. Unless there's something built into the switching unit to prevent either of these situations occuring, you need to make sure both amps are switched off before changing over. I know this sounds simple but it's easily overlooked.

Providing the valve amp is triode wired on the output it will be fine, triode's love an infinite load, how would choke loading work if they didn't?

Pentodes are a different matter.

-- Andrew

stewthedarrenner
25th November 2009, 02:17
The product number is TC-722, but I was looking for a suitable name as well. What about the Crossover Network:D?
that does look good stan, if its not a secret, any chance you could give some info on the circuitry/switching paths ?


and andy, if you do go for 2 sets of cables, theres always relays to switch between signals, it would save swapping plugs

Paramaribo
25th November 2009, 08:36
The circuitry is as simple as possible in order to avoid interference with the signal. The box relies on the user first selecting the amp and speaker combination he/she wishes to use, before switching on the amp.
You can't select two amps or two speakers for simultaneous use. The switches won't allow that type of operation for obvious safety reasons.
The box is not designed for 'life' switching. i.e. operation of any of the switches whilst the equipment is playing. I looked at that option, but came to the conclusion that such a feature would require use of circuitry that would likely interfere with the effective impedance seen by the amp.
Each amp and speaker earth point is isolated from any other earth point, this allowing for the uses of the box with amplifiers that have a bridged output.
The switches are rated by the manufacturer at 20A per contact. My box uses a double contact configuration, thus giving it a theoretical 40A handling ability through each signal path.
The solder used in certain parts is a special high temperature silver solder, instead of the regular lead free solder.
The internal wiring is a special type of OFC cable that is normally used in speaker switching units in high power applications on stage etc.
The case is 1.2mm steel that has been electro plated.

It might be a bit of over engineering compared to the El Cheapo boxes from your regular B-Tech etc. and Radio Shack stores, but I believe in sensible over engineering when it comes to speaker signal switching.

Chops54
25th November 2009, 19:06
That reads exactly as it should be :^

I've no need for speaker switching but I understand Andy's dilemma and I'll be over for a listen when he gets his switch box and gets it set up.

stewthedarrenner
25th November 2009, 21:21
ditto :)

Andy831
25th November 2009, 23:09
And ya both very welcome:cheers:

Paramaribo
9th February 2010, 08:45
Just a quick update. FEDEX is picking up my goods on Thursday from the factory, and deliver them to me next week Monday. So I shall have the item in stock next week.

Sorry about the delay everyone. My beta testers were taking their time in confirming that the switcher worked on a wide enough range of speakers that we had access to for testing.

Andy831
9th February 2010, 10:47
Looking forward to it Stan, let me now how and where you would like paying

DaveK
9th February 2010, 11:35
Hi Stan,
Irrespective of what Andy said last time (pissing on my chips, indeed :rolleyez: ), can I confirm that I am still number 1 in the queue for the switcher, and if you could put one of your (mythical? ;) ) vinyl cleaning kits in the package that would be great. Please PM me with invoice total and payment details and I'll forward the necessary.
Kind Regards,

Paramaribo
16th February 2010, 13:08
They are here :D. Just need to take some luvely pics for my site, do some write up for the web page, and work out the general price.
Of course, the price for the Andy and Dave are the beta TXN tester price with its benefits. I shall PM you guys once I obtain from FEDEX the exact amount I had to pay in import duty and VAT.

Andy831
16th February 2010, 14:59
Cheers Stan

DaveK
16th February 2010, 15:25
Of course, the price for the Andy and Dave are the beta TXN tester price with its benefits. I shall PM you guys once I obtain from FEDEX the exact amount I had to pay in import duty and VAT.

Hi Stan,
Thanks for the heads up - can I offer you one now :) ;) . Please don't forget the vinyl cleaning set, if you've got any left.
Thanks again,

Andy831
27th February 2010, 12:54
Switch paid for, and looking forward to it arriving. You ordered yours yet Dave?

Paramaribo
27th February 2010, 15:14
You mean this one:

http://www.homehifi.co.uk/images/TC-7220/TC-7220Sm.jpg

http://www.homehifi.co.uk/images/TC-7220/TC-7220F.jpg

Andy831
27th February 2010, 15:46
Looking Good Stan

Roksoff
27th February 2010, 16:31
That looks good Stan.
Love the name. :)
Are they WBT terminals?

DaveK
27th February 2010, 16:36
Switch paid for, and looking forward to it arriving. You ordered yours yet Dave?

Hi Andy,
Not only ordered, but payed for and, Stan being a man of his word, well en-route to me as we speak, probably half way up the M1 ;) .
And I can't wait - if it works as good as it looks, and I've no doubt it will, it will be great - thanks again Stan,
Dave.

Andy831
28th February 2010, 07:50
Suppose I need to get the soldering iron out today to prep some new speaker cables to feed into the switch box!

DaveK
28th February 2010, 11:43
Suppose I need to get the soldering iron out today to prep some new speaker cables to feed into the switch box!

Are you soldering terminals on the wires or just 'glueing' the fine wires together?

Andy831
28th February 2010, 20:10
Are you soldering terminals on the wires or just 'glueing' the fine wires together?

Soldering 4mm bananas onto some VD Hul cable I have, but time has got away from me today and I have not done it yet

Andy831
1st March 2010, 12:55
Arrived today and looks as good in the flesh as it did in the photographs

DaveK
1st March 2010, 13:05
+1 What he said, in Spades !!! ^ :)
Thanks Stan, great service and much appreciate the 'extras'.
As usual, a pleasure doing business with you, apart from the slight problem of parting with the money ;) .
Dave.

Paramaribo
1st March 2010, 19:38
+1 What he said, in Spades !!! ^ :)
Thanks Stan, great service and much appreciate the 'extras'.
As usual, a pleasure doing business with you, apart from the slight problem of parting with the money ;) .
Yeah, I know:rolleyez:. That's why there was no invoice for the extras. There goes the profit for my lunch tomorrow...

DaveK
1st March 2010, 22:26
Yeah, I know:rolleyez:. That's why there was no invoice for the extras. There goes the profit for my lunch tomorrow...

Hi Stan,
As Granny used to say, "Your reward will be in heaven" ;) - I just hope and pray it's not too soon :).
Many thanks, again,
Dave.

Batty
2nd March 2010, 03:26
A review gents please when you get the chance.