Since I am really only just beginning to get into electronics I figured it was best to ask this question here since I know there are some guys here that can answer it. I just got a Bitmo 10-Uator for my Epi VJ and you have to wire it up to a set speaker ohm level. The speaker in the VJ is 16 ohms, however, later down the road I'm thinking of changing it out for a Jensen that is 8 ohm. While I am not sure how easy of a change it is (maybe it is just changing a resistor? Dont know, haven't seen the instructions yet) I was wondering if anyone knew how bad it would be if I wired it for the 8 ohms, but ran my 16 ohms through it. I know there is some leeway with these things, but I am obviously not going to do anything that will fry my amp/myself/burn my house down/you get the idea. Thanks guys.
Attenuator thoughts..
- Thread starter rapfohl09
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line6man
Epic Member
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Running an 8 Ohm load on something designed to see a 16 Ohm load will cause an excessive consumption of current.
You would NOT want to use an 8 Ohm resistor in series with the speaker, as that would mean that half of your power is being wasted to dissipate thermal energy. Also, whether or not your resistor is inductive, it is still likely to mess with the frequency response.
If you need to change output impedances, you can usually do so with an impedance matching transformer.
I do know off hand that Glockenklang makes one specifically for guitar/bass amplifiers, but it is wound for 4 and 8 Ohms. (Also, why the hell is the power handling capability given in Watts and not VoltAmperes?)
http://www.glockenklang.de/en/products/bass_systems/impedance-transformer.htm
You would NOT want to use an 8 Ohm resistor in series with the speaker, as that would mean that half of your power is being wasted to dissipate thermal energy. Also, whether or not your resistor is inductive, it is still likely to mess with the frequency response.
If you need to change output impedances, you can usually do so with an impedance matching transformer.
I do know off hand that Glockenklang makes one specifically for guitar/bass amplifiers, but it is wound for 4 and 8 Ohms. (Also, why the hell is the power handling capability given in Watts and not VoltAmperes?)
http://www.glockenklang.de/en/products/bass_systems/impedance-transformer.htm
Superlizard
Hero Member
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- 2,514
Regarding t00b amps and speakers - the general rule of thumb is an upwards mismatch is "ok" (no guarantees):
8ohm amp -> 16ohm amp
But a downwards mismatch:
16ohm amp -> 8ohm amp
is a big no-no.
Optimal is of course a perfect match.
This above info, in general, has nothing to do with the typical attenuators found on the market today
in terms of damaging your OT with a mismatched load. Read further as to "why?" -
=====================================================================
Now, with this in mind, there's confusion when one purchases an attenuator. THD HotPlates, for
example, come in a variety of Ohm ratings.. and those not in the know assume that you cannot
run a 16ohm head to an 8 ohm HotPlate - not true.
Again, from the horse's mouth - to quote Ed DeGenaro
on a question I asked him years ago on the Plexi Palace BBS:
http://www.unofficialwarmoth.com/index.php?topic=7610.0
I myself have never futzed (nor heard of) with the Bitmo doo-jabby. I just checked it out
and it appears to have the same features as a HotPlate, but I'm not about to make
assumptions.
So, the question here is - is the Bitmo 10-ulator designed like the HotPlate (reactive load)?
In the case of the HotPlate, a matching sounds best because the tone network
(bright/deep switches) is designed around it... not because the load isn't mismatched
(and therefore would cause your OT to fry) - i.e. it's completely safe to use mismatched...
take note however that in Ed's examples, even though he's using a "mismatched"
attenuator, he's still making sure the amp head and speakers are matched.
When in doubt, stick to the basics - and keep things matched. Don't deviate from
that unless you know exactly what you're doing and the gear you're using.
8ohm amp -> 16ohm amp
But a downwards mismatch:
16ohm amp -> 8ohm amp
is a big no-no.
Optimal is of course a perfect match.
This above info, in general, has nothing to do with the typical attenuators found on the market today
in terms of damaging your OT with a mismatched load. Read further as to "why?" -
=====================================================================
Now, with this in mind, there's confusion when one purchases an attenuator. THD HotPlates, for
example, come in a variety of Ohm ratings.. and those not in the know assume that you cannot
run a 16ohm head to an 8 ohm HotPlate - not true.
Again, from the horse's mouth - to quote Ed DeGenaro
on a question I asked him years ago on the Plexi Palace BBS:
http://www.unofficialwarmoth.com/index.php?topic=7610.0
I myself have never futzed (nor heard of) with the Bitmo doo-jabby. I just checked it out
and it appears to have the same features as a HotPlate, but I'm not about to make
assumptions.
So, the question here is - is the Bitmo 10-ulator designed like the HotPlate (reactive load)?
In the case of the HotPlate, a matching sounds best because the tone network
(bright/deep switches) is designed around it... not because the load isn't mismatched
(and therefore would cause your OT to fry) - i.e. it's completely safe to use mismatched...
take note however that in Ed's examples, even though he's using a "mismatched"
attenuator, he's still making sure the amp head and speakers are matched.
When in doubt, stick to the basics - and keep things matched. Don't deviate from
that unless you know exactly what you're doing and the gear you're using.
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