DIY Audio Projects Forum

hi all.
to start off. this is my fist post so be lenient
the first question i want to ask is that, can i bi-wire a cambridge audio a1 mk3 special edition amp ? i got it as a debt from a friend so i dont really know much about it. i want to make a pair of floorstanding speakers in the future so im thinking of buying all the bits slowly. im thinking to make then around 45" high (give and take) with a 6" woofer, a midrange and a tweeter. or two woofers and a tweeter. im looking at peerless woofers as theyre pretty cheap because it will be my first proper project but that not my question.
can i bi-wire the cambridge audio. or do i even need to bi wire it ??
i also have a technics ch7 system (needs fixing) and a technics sa-GX470 (wouldnt mind using them if i must) ive just read around and got that bi wiring is better for sound and clarity. i will be using the best cables i can find. probably power cables 100% ofc copper with a thick core but i dont know yet.

(I WILL BE MAKING SPEAKER STANDS AND A HEADPHONE STAND ALSO SO I MAY MAKE A THREAD AND POST STEP BY STEP PICS ON HOW I DID IT IF ANYONE WANTS, IT WILL BE NICE TO HAVE YOUR OPINIONS)

untill then ANY REPLIES WILL BE APPRECIATED.
THANKS ALL IN ADVANCE !!

Hi and welcome to the forum.

When you bi-wire, you use a seperate amp for the woofer and the tweeters. So you will need to get another stereo amp if you would like to bi-wire your speakers. You don't need to bi-wire, it is an option that can improve the sound. Before you get too far down the road, I suggest you start here for the background info in bi wiring
http://sound.westhost.com/bi-amp.htm

Cheers

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[ DIY Mains AC Power Cable Cord ] - [ Gobo LM1875 Amp Kit ] - [ Tang Band D4-1 Horn Speaker Kit ] - [ Monoblock Push-Pull KT88 Tube Amp Kit ]

on speakers which can be bi/triwired theres a link between the drivers which is removed.
then separate cables from the amp is run to the terminals
there is no real benefit, people do it cos its cheap.
the last poster has got confused with biwiring and biamping.

Running 2 sets of wires from a single amplifier to a single speaker is certainly not cheaper - it's a complete waste of money and time. Your explanation makes no sense.

The purpose for bi-wire IS bi-amp. You want to power your woofers from one amp (preferably one that is particularly good for bass driving) and your mid-range & tweeters from another amp. Bi-wire and bi-amp go hand in hand, otherwise there's no reason to "bi-wire". Now, I don't know, but I would guess there are some higher end systems that come "bi-amp'd" in one unit and have separate woofer outputs and treble outputs - it's still bi-amping.

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The key to a successful build is to keep the smoke IN the circuit.
-Les

We cannot solve our problems with the same thinking we used when we created them. - Albert Einstien
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LM380 Bridged Guitar Amp, Oatley K301 Phono Pre-amp, Oatley K272 Headphone Amp, Tube proto-board

Whats the point of your post?

Do you have practical experiance of either:

a) bi/tri wiring
b)bi/tri amping
c)active crossover systems

You can get the pros and cons here: http://sound.westhost.com/bi-amp.htm#bi_wiring

I agree with Les and Rod. If you going to go to the effort of biwiring, you really need to take it to the next level (ie. biamping) to get the real performance benefits.

Cheers

_________________
[ DIY Mains AC Power Cable Cord ] - [ Gobo LM1875 Amp Kit ] - [ Tang Band D4-1 Horn Speaker Kit ] - [ Monoblock Push-Pull KT88 Tube Amp Kit ]

Without reading in detail all the post before I would like to add my two bobs worth:
I would never of bi-wired until the manufacturer of my Osborn's, Greg Osborn said "bi-wire". The Osborn Eclipse (my speakers) separate the woofer from the mid/tweeter at the binding posts. If I bi-amp the amp for the mid/tweeter would be looking into a purely capacitive load. I have heard where this can badly load tube amps and possibly cause damage. Not sure how SS amps would see this.

With my bi-wiring I run four lots of figure eight oxygen free medium weight speaker cable to each of the four binging posts. Each figure 8 is treated as a separate and single wire so no capacitive effects occur between any of the conductors which would normally happen if you use one of each of the two conductors for positive and negative speaker wires. Also my speaker wire runs are short.

If you bi-amp I feel you should only ever use two of exactly the same amps. Few people ever do with some using tube amps for mid/tweeter and SS amps for bass. The problem is here as both amps will pass the signal at different speeds resulting in time slurring of the original signal. Even two different SS amps will have different propagation delays (Matt will probably jump in about here).

For me: one amp, bi-wired is the way to go. But what do I know?

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Projects: "Sortilege" - 180W Tripath Class D Mundorf upgrade amp | “Mantra” - tube MM phono preamp | "Carbon” - MM phono preamp | 180W RAW Class D amp |

Hi Everyone, A tricky issue and one that generates differing opinions. I bi-wire my Martin Logan Vistas (ESLs) based on information from M-L. The drivers (conventional cone one for low frequencies under 450HZ and the ESL for everything else) present differing loads on amplifiers. To minimize the interaction of one and the other M-L recommends bi-wiring. The system is nominally a 4 ohm one, but drops to just over 1 ohm at 20KHZ. I'm sure there are a few ripples in there somewhere as well. Even the relatively small amount of resistance in the feed wires will be in series with the two drivers if they are tied together at the speaker end. With bi-wiring the interactions are limited only to the contribution of the amplifier. It would seem that amplifiers with very low output impedance (SS mostly) would work best with bi-wiring, but there doesn't seem to be any issues with my all tube ones. Right now I'm using an early pair of the KT120 mono blocks (45 WRMS Class A and U/L). I have used other tube amps with as little as 5 WRMS per channel and all was fine. BTW M-L recommends against bi-amping. As always....your results may be different.

Good Listening
Bruce

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Some of my DIY Tube Amplifier Projects:

• PoddWatt: 5751 / EL84 Push-Pull DIY Tube Amplifier Project
• OddBlocks: KT88 Push-Pull DIY Tube Amplifiers (Mono Blocks)
• ForeWatt: ECC802S (12AU7 / ECC82) DIY Tube Preamplifier Project
• GrooveWatt: Tube (Valve) RIAA Phono Preamplifier Project

Just my thoughts,

I have in the past Bi-wired speakers, some have a link that can be removed so the mid-range can be separated from the tweeter.
This is not Bi-Amping its running two sets of wire from the amp terminals one to the tweeter and one to the lower range.
So you have 4 wires two to the tweeter and two to the lower range.

My experience was improved clarity. To me Bi-amping is a different issue.

There are many ideas as why this could make a difference one of which is the lower frequencies driver used more current than the tweeter and can effect the signal over longer distances. There is a lot of talk about if the same wire should be used for both the tweeter and low range but that's up to different people. This was and is true even on dual concentric drivers where the tweeter can be bi-wired separately to the low range driver.

Then again there is a lot of talk about people using different cables and if they make a difference. Taking into account what cable type is used inside the amp what makes a difference and what doesn't.

To me there is a difference between LCOFC / OFC / Copper / Silver plated copper / Silver plated OFC. YMMV

There was also talk about RFI and speaker cables some say its a different issue some say its all part of the same thing.
On a tube amp there is a possibility of a step up effect of the output transformer that's just one thought.
There are many more ideas.

There is a lot of controversy linked to possible skin effect and that it doesn't apply to audio frequencies so its moot.
But RFI is not audio, then there is the case that where does high current run in a cable and higher frequencies low current run again perhaps its moot.
But silver plated cables should have no effect should they, a daft idea that the HF runs on the outer and the high current on the inner but that would be ridiculous and there is no physics to explain it. Then the HF would run next to the insulation and that would make a difference, of course this is rubbish there is no physics to back up the claims .

So what's right and what's moot. Perhaps you have to ask could you transmit HIFI audio in analogue on top of a mains supply with varying current and RFI.. interesting thought maybe.

Just to throw a red herring into the pot here is Mullards 3-3 schematic, note the 1K across the speaker terminals.
https://www.google.co.uk/search?q=mulla ... jE7Qs9M%3A

OK so what's it for, to keep the amp stable with disconnected speaker, possibly.
However 1K should have no effect on the signal because its got an 8 ohm winding etc.
OK so why do different resistor types sound different then? LOL
You will see it on the Mullard 10-10 etc and others.

Just as a last thought,
its obvious on tube amps take a look if it has global FB where is the output winding connected to (the input).
Just for fun of course because the SS band don't get away with it either.

Regards
M. Gregg

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What is the sound of one hand clapping?

Hi, usually we are on the same or at least similar wave lengths but you lost me here

Just as a last thought,
its obvious on tube amps take a look if it has global FB where is the output winding connected to (the input).
Just for fun of course because the SS band don't get away with it either.

On the rest I agree. After trying numerous cables (I have a large box of ones that can prove it) I find that pretty much any short (1-1.5m) cable that is 16 gauge or larger and is terminated with suitable connectors for the amps and speakers is hard to distinguish from any other one. OFC ones seem to be the choice and indeed unless you have a vast budget or leave the audio area (like industrial cables) are pretty much the only kind you can find. I have tried in the past some costly ones that incorporate what I consider snake oil . They sometimes did sound different (often not), but usually worse than just plain zip cord. YMMV, sorry guys who are believers in that stuff. Right now I use 14 gauge OFC designed for in wall use. It comes under several brands and works well with my KT120 mono blocks and Martin Logan ESLs. The latter for folks who are new to audio act like giant capacitors and drop from 4 ohms in the bass/mid range to 1.2 ohms at about 20K. If there was any scenario that would cause difficulties my set up would. It doesn't.

I am sure the controversy will continue and as long as someone can be convinced that 6 feet of wire that costs as much as a nice automobile improves the sound. Also there will be both someone who will swear by it and someone else to make a profit making it. I prefer to spend the money on the car.

Good listening
Bruce

_________________
Some of my DIY Tube Amplifier Projects:

• PoddWatt: 5751 / EL84 Push-Pull DIY Tube Amplifier Project
• OddBlocks: KT88 Push-Pull DIY Tube Amplifiers (Mono Blocks)
• ForeWatt: ECC802S (12AU7 / ECC82) DIY Tube Preamplifier Project
• GrooveWatt: Tube (Valve) RIAA Phono Preamplifier Project