2 pairs of ditton 25's into a Quad 405 ?

[landlesspeasant]

Hi there .

Can I wire 2 pairs of ditton 25's into a Quad 405 ? the amp has no output info on the back .. with one set of speaker out puts .. and the dittons say 4 to 8 ohms 60w on the back.

I recently found the online manual for the 405 with a section that would make me think its no problem .. but I need a 2nd opinion from some one with more knowledge .

Will I damage any thing ?



T.I.A . Dom

 

[landlesspeasant]

this is from the quad manual ... so can i bypass the switch in the diagram and just wire Sets A & B into the one set of terminals on the 405

 

[Galu]

I would not run the Quad 405 into a low speaker impedance like 4 ohm - I'd go no lower than 8 ohm.

(The 405-2 was an improved version better able to run into low impedance speaker loads.)

If you want to run two Ditton 25s from each channel of your 405, then wire each pair in series (not in parallel) to ensure a high impedance load (nominally 12 ohm).

The 405 is powerful enough (100W into 8 ohm) to go very loud with the 12 ohm series combination.

 

[Galu]

Will I damage any thing?

You will almost certainly damage the 405 by connecting each pair of Dittons in parallel, as that would result in a load impedance as low as 2 ohm on each channel.

Wire each pair in series only as I indicated in my prevous post.

 

[landlesspeasant]

.. Thats exactly what i needed to know



Thanks Galu ...

 

[landlesspeasant]

Thanks for your help Galu ... I've set them up ... 1st impresion is ... WOW ... But it might be a bit of a heavy load when turning it up really LOUD .. The sound has lost a little of its tightness of the bottom end . the attack seems a little stilted and a maybe a bit blurry on the decay at very loud .
I've been listening at just loud volume and messing about with the settings for a few hours now ... Its a great sound .. when you don't over work the 405 .. its alot of weight for it to move .. I think ?

I've only recapped one pair so this might also be a factor . . I'll probaby leave it like that for a month then go back to the single pair for retest ..

 

[Galu]

Its a great sound .. when you don't over work the 405 .. its a lot of weight for it to move .. I think ?

If you're worried about the higher impedance when a pair of Dittons are wired in series then don't be.

Rated at 4 to 8ohm per speaker, you're getting 8 to 16 ohm per series pair, the latter being a more comfortable load for the 405, if anything.

P.S. Like the speaker overkill look!

 

[landlesspeasant]

P.S. Like the speaker overkill look!



I've got them sitting on a pair of Tannoy 10" LZ -111 .. they need recapping too .. but they act as an extra bass reflex .. I was wondering what would happen if i closed the circuit on the tannoys with the energy being tranfered from the 25s on to the coil of the tannoys .. would it make any difference ?

 

[landlesspeasant]

Thanks for your help Galu ... I've set them up ... 1st impresion is ... WOW ... But it might be a bit of a heavy load when turning it up really LOUD .. The sound has lost a little of its tightness of the bottom end . the attack seems a little stilted and a maybe a bit blurry on the decay at very loud .
I've been listening at just loud volume and messing about with the settings for a few hours now ... Its a great sound .. when you don't over work the 405 .. its alot of weight for it to move .. I think ?

I've only recapped one pair so this might also be a factor . . I'll probaby leave it like that for a month then go back to the single pair for retest ..

 

[landlesspeasant]

I like the speaker over kill look too

 

[Galu]

I was wondering what would happen if i closed the circuit on the tannoys with the energy being tranfered from the 25s on to the coil of the tannoys .. would it make any difference ?

Not entirely sure what you mean, but I would caution against connecting the Tannoys at the same time as the Dittons.

An unknown, and possibly damaging, impedance will result and I wouldn't want to encourage you to blow up your 405!

 

[landlesspeasant]

The Tannoys are not gonna be connected to the amp .. I was thinking that as the driver is a coil around a magnet .. when it vibrates from the sound energy that is transferred thru the cabinets .At the volumes I like this is noticible ... there must be a small current generated ???
.. So what would happen if connected the + and - on the tannoys together .. no external power sorce .. As you can see .. I know nothing



Thanks again for your help ... I've been listening to the recapped 25's you helped me with last year .. And the sound has been fantastic, a deffo improvement .. Thanks

 

[Galu]

When a loudspeaker is used backwards, converting sound energy to electrical energy, it is acting as a microphone,

And, just like a microphone, the current generated is so small as to be useless without amplification.

So I'm afraid your idea has no merit, there would be insufficent electrical energy generated by either speaker to power the other.

 

[landlesspeasant]

Cheers .. for the info

 

[Galu]

I've been listening to the recapped 25's you helped me with last year .. And the sound has been fantastic, a deffo improvement ..

Ah yes, that was a fun thread! You ultimately became expert at choosing replacement capacitors i.e. the most appropriate type, voltage rating and capacitance value.

 

[Galu]

So I'm afraid your idea has no merit, there would be insufficent electrical energy generated by either speaker to power the other.

I take that back, the idea has some merit when making a simple intercom. I've just remembered doing this as a child:

Speaker-Phone from Junk Speakers - SciencetoyMaker

 

[landlesspeasant]

Ah yes, that was a fun thread! You ultimately became expert at choosing replacement capacitors i.e. the most appropriate type, voltage rating and capacitance value.

Expert is deffo the wrong word