Parallel speaker output jack help please!

[fourstringbliss]

I've recently ordered an Acoustic B200 combo and it has an external speaker jack on the back. The amp has a 4 ohm minimum and the speaker in the combo is 4 ohms.

The manual lists this external speaker jack as: Speaker Out: two-conductor , 1/4" speaker output jacks, 4 ohm minimum load, parallel.

What does that "parallel" mean here? Could I connect another 4 ohm cab here and have a total of 8 ohms or would it be a 2 ohm load? What would happen if I add an 8 ohm cab?

 

[bongomania]

Parallel halves two identical loads, so with a 4 ohm minimum you could only connect two 8 ohm cabs. You'll want to read the ohms FAQ.

 

[fourstringbliss]

Parallel halves two identical loads, so with a 4 ohm minimum you could only connect two 8 ohm cabs. You'll want to read the ohms FAQ.

Ohms facts... right.

That's a sticky huh?

 

[jtc_hunter]

Save yourself some money and just run a DI out to your mixer. If you need more stage volume, then let some bass come thru the monitors. And a whole lot more thru the mains.

 

[MIJ-VI]

I've recently ordered an Acoustic B200 combo and it has an external speaker jack on the back. The amp has a 4 ohm minimum and the speaker in the combo is 4 ohms.

The manual lists this external speaker jack as: Speaker Out: two-conductor , 1/4" speaker output jacks, 4 ohm minimum load, parallel.

What does that "parallel" mean here? Could I connect another 4 ohm cab here and have a total of 8 ohms or would it be a 2 ohm load? What would happen if I add an 8 ohm cab?

Hi fourstringbliss.

'Amps FAQ *** Now with info on OHMS, PORTABLE RIGS, & Over/Underpowering Cabs & DIY!': http://www.talkbass.com/forum/showthread.php?t=166225

 

[fourstringbliss]

Hi fourstringbliss.

'Amps FAQ *** Now with info on OHMS, PORTABLE RIGS, & Over/Underpowering Cabs & DIY!': http://www.talkbass.com/forum/showthread.php?t=166225

Thanks! It turns out the amp manual is wrong and the output jack is wired in series. Just another case of a combo amp with a useless external speaker jack. To use it I would need to disconnect the internal speaker first.

 

[B-string]

If it is a series jack then you leave the internal connected, add a 4 ohm cab and the total load will be 8 ohms on the amp (a little less power but more speaker area).

 

[jimmy rocket]

Series is correct. That was just noted in the new BP I found in my mailbox today.

Depending on what cab you're running it with (thinking 410 here), the extra air you're pushing might make those 8 ohms sound louder.

 

[fourstringbliss]

Series is correct. That was just noted in the new BP I found in my mailbox today.

Depending on what cab you're running it with (thinking 410 here), the extra air you're pushing might make those 8 ohms sound louder.

The Acoustic B200 was featured in BP?

If I added one of the 8 ohm Acoustic external cabs would the total load be 12 ohms?

 

[B-string]

Series is correct. That was just noted in the new BP I found in my mailbox today.

Depending on what cab you're running it with (thinking 410 here), the extra air you're pushing might make those 8 ohms sound louder.

That was my point, but not stated so well

 

[jimmy rocket]

The Acoustic B200 was featured in BP?

If I added one of the 8 ohm Acoustic external cabs would the total load be 12 ohms?

I series wiring, yes.

 

[MIJ-VI]

Thanks! It turns out the amp manual is wrong and the output jack is wired in series. Just another case of a combo amp with a useless external speaker jack. To use it I would need to disconnect the internal speaker first.

Well fsb, you could try **measuring/confirming the impedance of your Acoustic B200's internal speaker with a multi-meter (or remove the speaker and look for a label indicating whether said spkr is 4 or 8 ohms) since Acoustic Amplification seems to offer two different 8 ohm extension cabinets for the B200. This would imply that your amp's internal spkr is indeed 8 ohms.

**Hopefully someone more technically adept than myself will chime in on how to meter/measure a speaker's impedance.

HOWEVER, Musician's Friend claims that the B200's full 200 watts (@ 4 ohms min.) is going into its internal speaker, which would indicate that it's 4 ohms:

From 'Musician's Friend':

"The Acoustic B200 professional combo is designed for large club and live applications where the sound of its 15" bass driver and horn will fill the stage with warmth and punch. That's because it pounds a massive 200 watts RMS into the internal 15" speaker,.."

Acoustic B200 200W 1x15 Bass Combo Specifications:

* 20"W x 24-3/4"H x 15"D
* 75 lbs.

Acoustic B200 200W 1x15 Bass Combo Features:

* Power: 200 Watts @ 4 Ohms
* Speaker: 15" Heavy-duty speaker, built-in horn
* Channels: 1
* EQ: 6-Band EQ - sweepable
* Frequency notch filter
* Inputs: dual inputs (passive & active)
* Outs: XLR direct out
* Caster sockets (casters sold separately)

Invalid Link Removed

--------

Conflicting Info from 'Acoustic Amplification':

OPTIONS (for the B200):
*B115 1x15 Bass Cabinet (8 ohms)
B410 4x10 Bass Cabinet (8 ohms)

Invalid Link Removed

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'Acoustic® *B115 professional enclosure':

POWER: 250 Watts Power Handling
SPEAKER: 15" Heavy-Duty Speaker, high-frequency horn with on/off switch
IMPEDANCE: 8 Ohms
INPUT: Parallel 1/4" Input Jacks

Invalid Link Removed

--------

'Acoustic® B410 professional enclosure':

POWER: 400 Watts Power Handling
SPEAKER: 4 x 10" Heavy Duty Speakers, high-frequency with on/off switch
IMPEDANCE: 8 Ohms
INPUT: Parallel 1/4" Input Jacks

Invalid Link Removed

--------

It looks like you'll have to meter (or pull) your B200's speaker to confirm what its impedance actually is before plugging in an extension cabinet and possibly damaging your amp.

What a way to sell gear, eh?

 

[fourstringbliss]

The B200 manual says it's a 4 ohm speaker. I've seen this kind of thing before - the SWR Workingpro 12 I just sold was 200w at 4 ohms and the internal speaker was 4 ohms, but it had a speaker out jack.

What I'm gathering here is that I could hook up another 4 ohm cab and I'd be getting a combined 8 ohms since the jack is series. Lower output from the amp but more speaker area. I figure it'd probably be a wash in the end, though.

Well fsb, you could try **measuring/confirming the impedance of your Acoustic B200's internal speaker with a multi-meter (or remove the speaker and look for a label indicating whether said spkr is 4 or 8 ohms) since Acoustic Amplification seems to offer two different 8 ohm extension cabinets for the B200. This would imply that your amp's internal spkr is indeed 8 ohms.

**Hopefully someone more technically adept than myself will chime in on how to meter/measure a speaker's impedance.

HOWEVER, Musician's Friend claims that the B200's full 200 watts (@ 4 ohms min.) is going into its internal speaker, which would indicate that it's 4 ohms:

From 'Musician's Friend':

"The Acoustic B200 professional combo is designed for large club and live applications where the sound of its 15" bass driver and horn will fill the stage with warmth and punch. That's because it pounds a massive 200 watts RMS into the internal 15" speaker,.."

Acoustic B200 200W 1x15 Bass Combo Specifications:

* 20"W x 24-3/4"H x 15"D
* 75 lbs.

Acoustic B200 200W 1x15 Bass Combo Features:

* Power: 200 Watts @ 4 Ohms
* Speaker: 15" Heavy-duty speaker, built-in horn
* Channels: 1
* EQ: 6-Band EQ - sweepable
* Frequency notch filter
* Inputs: dual inputs (passive & active)
* Outs: XLR direct out
* Caster sockets (casters sold separately)

Invalid Link Removed

--------

Conflicting Info from 'Acoustic Amplification':

OPTIONS (for the B200):
*B115 1x15 Bass Cabinet (8 ohms)
B410 4x10 Bass Cabinet (8 ohms)

Invalid Link Removed

--------

'Acoustic® *B115 professional enclosure':

POWER: 250 Watts Power Handling
SPEAKER: 15" Heavy-Duty Speaker, high-frequency horn with on/off switch
IMPEDANCE: 8 Ohms
INPUT: Parallel 1/4" Input Jacks

Invalid Link Removed

--------

'Acoustic® B410 professional enclosure':

POWER: 400 Watts Power Handling
SPEAKER: 4 x 10" Heavy Duty Speakers, high-frequency with on/off switch
IMPEDANCE: 8 Ohms
INPUT: Parallel 1/4" Input Jacks

Invalid Link Removed

--------

It looks like you'll have to meter (or pull) your B200's speaker to confirm what its impedance actually is before plugging in an extension cabinet and possibly damaging your amp.

What a way to sell gear, eh?

 

[shaolinwhat]

If it is a series jack then you leave the internal connected, add a 4 ohm cab and the total load will be 8 ohms on the amp (a little less power but more speaker area).

this is good to know. ive got an swr bigfoot, 2 12's @ 4 ohms, and my head only goes down to 4 ohms. the cab has a speaker out jack and i was curious how that would work.

 

[Stumbo]

Or a bypass jack could be installed providing a parallel setup. Then you could get a couple of 8 ohm 2x15 cabs and blast away for your bigger gigs. Or maybe a couple of 8 ohm 1x10 cabs from BFM. Now that would get you some bass.

 

[MIJ-VI]

The B200 manual says it's a 4 ohm speaker. I've seen this kind of thing before - the SWR Workingpro 12 I just sold was 200w at 4 ohms and the internal speaker was 4 ohms, but it had a speaker out jack.

What I'm gathering here is that I could hook up another 4 ohm cab and I'd be getting a combined 8 ohms since the jack is series. Lower output from the amp but more speaker area. I figure it'd probably be a wash in the end, though.

Well fsb, the good news is that your B200 appears to be pinned as is, therefore there's no need to $pend dough schlepping more gear.

If your amp's XLR out sounds good, then you can do as another poster has suggested and exploit PA support when it's available.

I must say that this is the first time I've heard of an extension speaker-capable transistor bass combo whose ext. spkr. jack is not wired in parallel with its internal driver. 'Weird...

 

[fourstringbliss]

Well fsb, the good news is that your B200 appears to be pinned as is, therefore there's no need to $pend dough schlepping more gear.

If your amp's XLR out sounds good, then you can do as another poster has suggested and exploit PA support when it's available.

I must say that this is the first time I've heard of an extension speaker-capable transistor bass combo whose ext. spkr. jack is not wired in parallel with its internal driver. 'Weird...

I think I'm just going to stick with the combo. This thing is startlingly loud on it's own. It's 200w but it sounds much louder. I just sold a 200w SWR Workingpro 12 (200w into 4 ohms with a 4 ohm internal speaker) and the B200 blows it away. I think it must be the larger cabinet on the B200, but I also wonder about the "200w" rating on the Workingpro.

 

[MIJ-VI]

this is good to know. ive got an swr bigfoot, 2 12's @ 4 ohms, and my head only goes down to 4 ohms. the cab has a speaker out jack and i was curious how that would work.

Hi shaolinwhat.

Your cabinet's jacks are wired in parallel, likely to accommodate the use of two of these cabs with more powerful amps which can support 2 ohm loads.

Bigfoot 2x12:

"Full Range Input and Output Jacks
The Bigfoot features three, full range input/output jacks (two standard 1/4" and one banana) wired in parallel. If you are running two speaker enclosures in parallel, connect the speaker cable from your amplifier to the 1/4" jack labeled “IN”, and a second speaker cable from the 1/4" jack labeled “OUT” to the input of the second speaker enclosure."

Bigfoot 2x12 Specifications:

Description: 2x12 + Tweeter Speaker Enclosure
This light weight enclosure featured high power capabilities, singing mids and earth-shaking lows.
Power Handling Capacity: 500 Watts RMS (Hmm...)
Impedance: 4 Ohms
Frequency Response & SPL: 95 dB SPL @ 1W1M (-3db @ 40Hz and 15KHz)
Speaker Complement: (2)12" Bag End drivers, (1) Le Son ferro-electric tweeter
Porting: Front Tube Ports
Size: 23 3/8"W x 23 3/8"H x 18.5"D
Weight: 65 lbs

Invalid Link Removed

 

[MIJ-VI]

I think I'm just going to stick with the combo. This thing is startlingly loud on it's own. It's 200w but it sounds much louder. I just sold a 200w SWR Workingpro 12 (200w into 4 ohms with a 4 ohm internal speaker) and the B200 blows it away. I think it must be the larger cabinet on the B200, but I also wonder about the "200w" rating on the Workingpro.

I'd expect that a difference in speaker efficiency between these two amps (in addition to the difference in spkr. & cab size) plays into their achievable volume levels as well.

A 12" typically won't deliver as much bass energy as a 15". Coaxing more lows out of a speaker is usually achieved at the expense of sensitivity.

Two examples from Celestion:

Please note the differences/tradeoffs in: sensitivity; freq. range; and Xmax (cone excursion) between the 'Green' and the 'Orange'.

'Green Label' 12" Neo Bass Spkr: Invalid Link Removed

(BTW. This is the speaker used in Traynor's recent DynaBass 300 combo, and its matching TC112 extension cab.)

BN12-300X (Taken from its .pdf spec. sheet)

General Parameters

Nominal diameter. . . . . . . . . . . . . . . . . 304.8mm/12in
Power Rating (rms) . . . . . . . . . . . . . . . . . . . . . . 300W
Nominal impedance . . . . . . . . . . . . . . . . . . . . . . . . 8Ω
Voice coil diameter . . . . . . . . . . . . . . . . 63.5mm/2.5in
Magnet type . . . . . . . . . . . . . . . . . . . . . . . Neodymium
Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95dB
Frequency range . . . . . . . . . . . . . . . . . . . . 40-3000Hz
Coil material . . . . . . . . . . . . . . . . . . . . . . . . . . . Copper
Former material . . . . . . . . . . . . . . . . . . . . . . Polyimide
Cone material . . . . . . . . . . . . . . . . Kevlar loaded paper
Surround material . . . . . . . . . . . . . . . . . . Cloth-sealed
Xmax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4mm/0.15in
Gap depth . . . . . . . . . . . . . . . . . . . . . . . . . 8mm/0.31in
Voice coil winding width . . . . . . . . . . . . 16mm/0.62in

--------

'Orange Label' 12" Neo Bass Spkr: Invalid Link Removed

BN12-300S (Taken from its .pdf spec. sheet)

General Parameters

Nominal diameter. . . . . . . . . . . . . . . . . 304.8mm/12in
Power rating (rms) . . . . . . . . . . . . . . . . . . . . . . . 300W
Nominal impedance . . . . . . . . . . . . . . . . . . . . . . . . 8Ω
Voice coil diameter . . . . . . . . . . . . . . . . 63.5mm/2.5in
Magnet type . . . . . . . . . . . . . . . . . . . . . . . Neodymium
Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99dB
Frequency range . . . . . . . . . . . . . . . . . . . . 50-4000Hz
Coil material . . . . . . . . . . . . . . . . . . . . . . . . . . . Copper
Former material . . . . . . . . . . . . . . . . . . . . . . Polyimide
Cone material . . . . . . . . . . . . . . . . Kevlar loaded paper
Surround material . . . . . . . . . . . . . . . . . . Cloth-sealed
Xmax . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5mm/0.098in
Gap depth . . . . . . . . . . . . . . . . . . . . . . . . . 8mm/0.31in
Voice coil winding width . . . . . . . . . . . . 13mm/0.51in

As you can see, the 'Orange' is 4db LOUDER (roughly equivalent to doubling an amp's wattage) than the 'Green'--but not where it counts for bass players.

 

[shaolinwhat]

Hi shaolinwhat.

Your cabinet's jacks are wired in parallel, likely to accommodate the use of two of these cabs with more powerful amps which can support 2 ohm loads.

Bigfoot 2x12:

"Full Range Input and Output Jacks
The Bigfoot features three, full range input/output jacks (two standard 1/4" and one banana) wired in parallel. If you are running two speaker enclosures in parallel, connect the speaker cable from your amplifier to the 1/4" jack labeled “IN”, and a second speaker cable from the 1/4" jack labeled “OUT” to the input of the second speaker enclosure."

Bigfoot 2x12 Specifications:

Description: 2x12 + Tweeter Speaker Enclosure
This light weight enclosure featured high power capabilities, singing mids and earth-shaking lows.
Power Handling Capacity: 500 Watts RMS (Hmm...)
Impedance: 4 Ohms
Frequency Response & SPL: 95 dB SPL @ 1W1M (-3db @ 40Hz and 15KHz)
Speaker Complement: (2)12" Bag End drivers, (1) Le Son ferro-electric tweeter
Porting: Front Tube Ports
Size: 23 3/8"W x 23 3/8"H x 18.5"D
Weight: 65 lbs

Invalid Link Removed

wait so either way it would still end up being 2 ohms?

and yea, the 65 lbs was a major factor in replacing my svt 810 with this guy