impedence

[munkonthehill]

Hello,

I have read a few pages on impedence but i dont think i quite have the brain power with this electric stuff(i practice in law).

ok here we go, I have a hughes & Kettner BK200.

it has a 1/4" jack output for an external speaker, does this mean an extention cab?

it states it runs at 4-8 ohm.in the instruction booklet it states the speaker runs at 4ohm and the tweeter runs at 4ohm.

does this mean that if both the speaker and the tweeter are in operation(tweeter can be switched off) that i cannot run anything further as im using the maximum ohms the amp can handle?

Like i said i have read up on this impedence stuff but im non the wiser. jez is selling an ashdown 2x10 cab at 8 ohms, would this be suitable for me?

this has probably been explained time and time again, but please for the love of god help me. I would say im losing hair over this but just check ma picture hahaha

[jezzaboy]

Monkman

Cant answer your question but get across here and buy the cab before I change me mind about selling, LOL. It`s a bloomin bargin!

Looking at the spec page I think that the 2x10 cab would allow your amp to work to it`s full potential. And yep that`s an external speaker output.

But dont take my word for it, wait until somone with more sense comes along.....

Jez

[Mr. Foxen]

A tweeter at 4 ohm and a woofer (speaker) at 4 ohm would still be 4 ohm together, they just cover different parts of the frequency range. Usually a combo will be 8 ohm itself, and be happy with another 8 ohm cab to make 4 ohm overall. A 4 ohm combo with an extension out seems odd.

[Moos3h]

Yep, just take the internal speaker resistance - so connecting an 8 ohm cab as well will give you the 4 ohms the amp requires to deliver the full 200w.

1x15 and 2x10 is a pretty classic setup, I think you'll like it!

[jezzaboy]

And behold, people with more sense did come along....Now Steve get your raincaot on and buy the cab.

Jez

[Musky]

Now that's unusual. From the manual:

[quote]External Speaker: This is a serial connection socket for speakers that connects the internal speaker in series with the additionally connected one. As the resistance adds on the internal resistance, even speakers with low impedances can be connected.[/quote]

So the amp is running at 4 ohms at the moment, and adding an 8 ohm cab would give you a total impedance of 12 ohms.

[Mr. Foxen]

[quote name='Musky' post='612485' date='Sep 29 2009, 09:16 PM']Now that's unusual. From the manual:



So the amp is running at 4 ohms at the moment, and adding an 8 ohm cab would give you a total impedance of 12 ohms.[/quote]

Series connection, suppose its safer on SS heads, will still give more volume. More speakers > more watts.

[munkonthehill]

[quote name='Musky' post='612485' date='Sep 29 2009, 09:16 PM']Now that's unusual. From the manual:



So the amp is running at 4 ohms at the moment, and adding an 8 ohm cab would give you a total impedance of 12 ohms.[/quote]


so what does this mean??? is running a 8 or 4 ohm speaker going to be detrimental to my amp, im still very hazey on the purpose of impedance levels

[Musky]

[quote name='munkonthehill' post='612499' date='Sep 29 2009, 09:30 PM']so what does this mean??? is running a 8 or 4 ohm speaker going to be detrimental to my amp, im still very hazey on the purpose of impedance levels[/quote]

Because the output is wired in series, the impedance of any cab you plug in to the combo will be added to the existing 4 ohms of the speaker already in there. Like the manual says, you can add any impedance speaker to the combo and it won't damage it. Solid state amps only run into trouble if you try running them at lower than the minimum impedance. Take a quick look at the wiki for the differences between series and parallel wiring.

[munkonthehill]

ok so final questions, is my amp currently delivering 200watts?
if i added a 200watt cab will i have 200watts being delivered from both amp and cab?

and finally will this have a major impact in my overall loudness and presence?

[GreeneKing]

[quote name='munkonthehill' post='613353' date='Sep 30 2009, 10:09 PM']ok so final questions, is my amp currently delivering 200watts?
if i added a 200watt cab will i have 200watts being delivered from both amp and cab?

and finally will this have a major impact in my overall loudness and presence?[/quote]

If the amp has a max output of 200 watts or thereabout into 4 ohm, and you add an extension cab in [b]series[/b] to increase the impedance seen by the amp then the output will fall.

The whole idea of a 4 ohm combo with a series output to increase the impedance seems strange to say the least.

I'd argue that adding an extension cab to an amp that will have its output reduced is a waste of time.

[warwickhunt]

[quote name='GreeneKing' post='613372' date='Sep 30 2009, 10:31 PM']If the amp has a max output of 200 watts or thereabout into 4 ohm, and you add an extension cab in [b]series[/b] to increase the impedance seen by the amp then the output will fall.

The whole idea of a 4 ohm combo with a series output to increase the impedance seems strange to say the least.

I'd argue that adding an extension cab to an amp that will have its output reduced is a waste of time.[/quote]

I have to agree... is it a typo in the manual?

re. the OP comment:

"ok so final questions, is my amp currently delivering 200watts?
if i added a 200watt cab will i have 200watts being delivered from both amp and cab?

and finally will this have a major impact in my overall loudness and presence?"

Adding more speakers will give you a greater spread and get the drivers nearer your ears BUT it will be offset by the reduction in power! I wouldn't worry too much about [u]what[/u] is being delivered from [u]where[/u]; power is from the amp, your cab simply has a rating based on what it can take... but that is very misleading so don't pay 'too' much heed to it.

First things first, establish if the output on your combo is genuinely series.

[GreeneKing]

I checked the manual online as well as the website specs and they both say the same thing - series

[munkonthehill]

amazing, so overall if I do add a cab then i lose power and wattage, kinda defeats the purpose of having the output socket!!!!!!!!

[munkonthehill]

now that i cant add a cab without losing power, can anyone tell me if this amp will hold up in a gig, i ususally gig to about 50-100people. it has 200watts going into a 15"driver, any thoughts guys

[GreeneKing]

That seems to be the case

If you can borrow a cab you can always 'suck it and see'.

If not maybe replacing it is your best option, it'll be a fine combo by itself for someone.

[chris_b]

[quote name='munkonthehill' post='614144' date='Oct 1 2009, 07:30 PM']....so overall if I do add a cab then i lose power and wattage, kinda defeats the purpose of having the output socket!!!!!!!!....[/quote]
You're right, which is why, as no other combo that I have ever seen has been built like this, I don't believe it! I'd drop HK an email and find out what is going on.

As has been said before, I think this combo should be 8 ohm going to 4 ohm with the addition of an 8 ohm extension cab.

Edited October 1, 2009 by chris_b

[munkonthehill]

but how would 200watts hold up?is this not going to be enough power or will this amp be sufficiant with its output

[warwickhunt]

I'd be inclined to think that it would be an 8ohm cab as well... here's a thought; get the speaker out and see if it has the impedance marked/labelled on it. If it is 8ohms I'd be amazed if it weren't a parallel socket and intended to operate at 4 ohms with an 8 ohm extension cab.

I owned a H&K BassBase 250 combo that had a 4 ohm internal speaker load but it DIDN'T have an extension socket.

[GreeneKing]

The manual says that the driver is 4ohm (with a 4ohm tweeter). If 4 ohms is the nominal impedance I can see why the extension o/p is in series although why bother

[warwickhunt]

[quote name='GreeneKing' post='614180' date='Oct 1 2009, 08:06 PM']The manual says that the driver is 4ohm (with a 4ohm tweeter). If 4 ohms is the nominal impedance I can see why the extension o/p is in series although why bother [/quote]

Do you believe everything you read Peter?

I've known some 'right' clangers in manuals (though I do confess that the H&K ones are better than most ) but unless I saw something with my own eyes (or heard it with my own ears perhaps) I'd not be inclined to have great faith in the printed word.

[GreeneKing]

No John not at all (I did used to be a copper - ABC, Accept nothing, Believe nobody and Check everything out), BUT, it would help explain why the extension might be in series. If you get my drift?

[warwickhunt]

[quote name='GreeneKing' post='614199' date='Oct 1 2009, 08:31 PM']No John not at all (I did used to be a copper - ABC, Accept nothing, Believe nobody and Check everything out), BUT, it would help explain why the extension might be in series. [b][u]If you get my drift[/u][/b]?[/quote]

Absolutely! If it is a 4ohm internal speaker then any extension will likely as not be in series but that has to be the daftest extension option EVER.

[Musky]

[quote name='munkonthehill' post='614160' date='Oct 1 2009, 07:47 PM']now that i cant add a cab without losing power, can anyone tell me if this amp will hold up in a gig, i ususally gig to about 50-100people. it has 200watts going into a 15"driver, any thoughts guys[/quote]

The answer is... it might do. Or not.

The problem is that the wattage actually tells you very little about the volume you're going to achieve, and even less about how that's going to fit in with your band. A 200 watt amp plugged in to one of Bill Fitzmaurice's (very efficient) cabs will sound about twice as loud as if the same amp was plugged into an inefficient Acme cab.

You've then got to consider your EQ - scooping the mids will mean your bass won't cut through as well, so you might find yourself needing more volume to hear yourself. And likewise if you've got a loud guitarist and drummer.

I'll stick my neck out and suggest for the size gigs you're playing that the amp will be loud enough. I play with an SWR combo that is only knocking out about 120w into it's internal speaker, but I've still had an engineer come up after a gig and tell me that he had to pull my bass from the PA because I was too loud.

But like I said, it all depends.

[munkonthehill]

i finally got a reply from H&K.

As the speaker output is wired in series you can use either a 4 ohm or an 8 ohm speaker. I would advise going for the 4 ohm option and make sure it’s rated around 200 watts. In terms of output produced, in theory it will be less because the overall impedance will have been increased but in practice it will probably sound about the same but the definition will be better as the extra speaker will share the load.

so there you go, not even the engineers can tell me what kinda output i will have....