the Official Ampeg Club Part 5

[dfp]

I have the V7.
Using just one cabinet…doesn't that only use half the amount of watts the amp is rated at because it's an eight ohm cab?

You said you were using two 1x12 cabinets, that's what I'm asking is the ohms difference with one cab or two cabs, make the volume difference I'm seeking?
I guess my question is; i'd like to run it lower or even the same, and be louder and not push the speaker as much, would it make sense to get a matching VB-115 or do use the VB-112 I that have or one of the other cab options?
Weight is not an issue, these are those super light cabs.

Bc you already have the VB112 try pairing that with the VB115 you also have. It might be just what you're looking for. It's been posted here before that those two go well together.

Yes running one 8 ohm cab cuts this amp's available watt output by half (compared to running a 4 ohm load) but 350 watts is a lot of power to work with. I use a pair of cabs bc I want a bigger sound and more air movement that 2 cabs provide, less to do with watts, headroom, settings, etc.

 

[rpavich]

Bc you already have the VB112 try pairing that with the VB115 you also have. It might be just what you're looking for. It's been posted here before that those two go well together.

Yes running one 8 ohm cab cuts this amp's available watt output by half (compared to running a 4 ohm load) but 350 watts is a lot of power to work with. I use a pair of cabs bc I want a bigger sound and more air movement that 2 cabs provide, less to do with watts, headroom, settings, etc.

Thanks!
I'll give that a try, if it works…I'm good

 

[rpavich]

Another question occurred to me about specifically those VB cabinets.

I see that they have horns in them or ports I guess, and there's a switch for attenuation or off or whatever, I've never really noticed a difference with the switch one one direction. Can anybody explain to me and more detail what the story is with those, what they add, why use them out not?

Just as an aside, I'm so thankful that those cabinets are so light, I'm 65 and I could lug them with one hand each!

 

[dfp]

Horns and ports are 2 completely different things. Horns are high frequency tweeters. Ports are openings in the cab that allow the speaker to function as a bass reflex system, ie a ported bass cab. This has the effect of letting the cab reach a little lower than it would otherwise reach.

If you can't hear a difference in the horn settings you might have those high frequencies already EQ'ed out, or maybe you just can't hear those high frequencies anymore! Try maxing the horn and turn up some treble, just to see if your horn works. If you don't want to emphasize those frequencies leave the horns off and enjoy.

 

[Wasnex]

I have the V7.
Using just one cabinet…doesn't that only use half the amount of watts the amp is rated at because it's an eight ohm cab?

AFAIK Ampeg does not publish the specs for 8 ohm operation. Usually solid state amp make more power as the impedance goes down, so this is a good assumption. I will assume the amp makes 350W at 8 ohms. I do not know for sure if this is correct, but it's the way many class D amps work.

Power by itself does not tell you have loud the rig will play. Basically when the power doubles, the volume goes up by 3dB, which is a small but noticeable difference.

You also need to consider the sensitivity rating of the speaker(s). Let's assume we have a VB-112 with a Sensitivity rating of 99dB 1W/1m. This means when 1 Watt is applied you measure 99dB at a distance of 1 meter from the driver.

Let's assume the amp makes 350W with one 8 ohm cab. The VB-112 is rated for 250W AES so usable power is only 250W. You can can estimate the SPL with the 3dB rule.
1W = 99dB
2W = 102dB
4W = 105dB
8W = 108dB
16W = 111dB
32W = 114dB
64W = 117dB
128W = 120dB
256W = 123dB*

* The usable power is slightly less than 256W, so available SPL is bit lower than 123dB.
You can also calculate the SPL if you know the 1W/1m sensitivity rating and the useable power.

Formula: Calculated SPL = 10Log(Usable Power) + Sensitivity

Calculated SPL = 10Log(250) + 99 = ~122.98dB

If you add a matching cab, it's normally going to be connected in parallel. So the combined impedance will be 1/2, combined power handling will be double, and combined sensitivity will be +3dB. So a pair of DB-112s will present a 4 ohm load, handle 500W, and have a sensitivity of ~102dB 1W/1m

If usable power doubles the you get +3dB from doubling the power in addition to the +3dB from the increase in sensitivity.

Calculated SPL for two cabs at 500W

• 10Log(500) + 102 = ~128.99dB

To use the full power of the V7, you need a pair of VB-212 cabs. These are 8 ohm cabs with a 500W power rating and 101dB 1W/1m Sensitivity. A pair of these cabs will present a 4 ohm load, so the amp will be able to make 700W. Combined power handling is 1000W, so to cabs can use all of the power. Combined Sensitivity is 105dB 1W/1m

Calculated SPL = 10Log(700) + 105-4 = 132.45dB.

The drivers will experience some power compression as they approach full power, so real world results will be a bit lower. But a V7 with a pair of VB-212s should be a pretty potent rig.

Ref for cab specs (see p. 6: https://ampeg.com/data/6/0a020a4168...df/Venture Cabs Owner's Manual - English .pdf

 

[rpavich]

Horns and ports are 2 completely different things. Horns are high frequency tweeters. Ports are openings in the cab that allow the speaker to function as a bass reflex system, ie a ported bass cab. This has the effect of letting the cab reach a little lower than it would otherwise reach.

If you can't hear a difference in the horn settings you might have those high frequencies already EQ'ed out, or maybe you just can't hear those high frequencies anymore! Try maxing the horn and turn up some treble, just to see if your horn works. If you don't want to emphasize those frequencies leave the horns off and enjoy.

Its a horn, but I just realized I'm pretty deaf in that region of hearing, so it might just be me

 

[dfp]

AFAIK Ampeg does not publish the specs for 8 ohm operation. Usually solid state amp make more power as the impedance goes down, so this is a good assumption. I will assume the amp makes 350W at 8 ohms. I do not know for sure if this is correct, but it's the way many class D amps work.

Power by itself does not tell you have loud the rig will play. Basically when the power doubles, the volume goes up by 3dB, which is a small but noticeable difference.

You also need to consider the sensitivity rating of the speaker(s). Let's assume we have a VB-112 with a Sensitivity rating of 99dB 1W/1m. This means when 1 Watt is applied you measure 99dB at a distance of 1 meter from the driver.

Let's assume the amp makes 350W with one 8 ohm cab. The VB-112 is rated for 250W AES so usable power is only 250W. You can can estimate the SPL with the 3dB rule.
1W = 99dB
2W = 102dB
4W = 105dB
8W = 108dB
16W = 111dB
32W = 114dB
64W = 117dB
128W = 120dB
256W = 123dB*

* The usable power is slightly less than 256W, so available SPL is bit lower than 123dB.
You can also calculate the SPL if you know the 1W/1m sensitivity rating and the useable power.

Formula: Calculated SPL = 10Log(Usable Power) + Sensitivity

Calculated SPL = 10Log(250) + 99 = ~122.98dB

If you add a matching cab, it's normally going to be connected in parallel. So the combined impedance will be 1/2, combined power handling will be double, and combined sensitivity will be +3dB. So a pair of DB-112s will present a 4 ohm load, handle 500W, and have a sensitivity of ~102dB 1W/1m

If usable power doubles the you get +3dB from doubling the power in addition to the +3dB from the increase in sensitivity.

Calculated SPL for two cabs at 500W

• 10Log(500) + 102 = ~128.99dB

To use the full power of the V7, you need a pair of VB-212 cabs. These are 8 ohm cabs with a 500W power rating and 101dB 1W/1m Sensitivity. A pair of these cabs will present a 4 ohm load, so the amp will be able to make 700W. Combined power handling is 1000W, so to cabs can use all of the power. Combined Sensitivity is 105dB 1W/1m

Calculated SPL = 10Log(700) + 105-4 = 132.45dB.

The drivers will experience some power compression as they approach full power, so real world results will be a bit lower. But a V7 with a pair of VB-212s should be a pretty potent rig.

Ref for cab specs (see p. 6: https://ampeg.com/data/6/0a020a4168b1651f29a4c0f0a/application/pdf/Venture Cabs Owner's Manual - English .pdf

I'm going from memory but I was thinking someone who had worked on the Venture amps commented on TB that the 8 ohm operation of the Venture amps was in fact effectively just 1/2 their 4 ohm potential.

I remember thinking that was interesting bc I thought most amps were capable of more than half their 4 ohm potential at 8 ohms.

 

[Wasnex]

I'm going from memory but I was thinking someone who had worked on the Venture amps commented on TB that the 8 ohm operation of the Venture amps was in fact effectively just 1/2 their 4 ohm potential.

I remember thinking that was interesting bc I thought most amps were capable of more than half their 4 ohm potential at 8 ohms.

AFAIK, That's way most Class D bass amp works.

Sucks that Ampeg doesn't bother to publish the spec.

 

[Murph_Orpheus]

Ok...first POST GIG report and question!

We played, I had the venture V7 head at 2pm on the gain and 2:30 or 3:00 on the master and used the SVT switch but little fuzz for a little added volume to be heard clearly in the band mix...not sure how advisable that is...it seemed like it was working hard to get that amount of volume to the crowd (about 150 folks) it was outdoors...under a stage over hang but the audience just had bench/tables and umbrellas.

I took the VB-115 as the cab (250w)

I have also a VB-112 at home.

I THINK I could use a second cab....more headroom for that volume...should I just also hook up the VB-112 OR get a second cab with a larger or more speakers (VB-115 or VB-212)?

I'm just looking to play at that volume but to be able to turn down and not push the head that hard for that sound volume...

Please advise...I"m still confused about volume vs speakers vs watts...

PS: Nothing was boiling hot after the 3 hour gig and the speaker box seemed to be ok no issues.

Also keep in mind the taper on the master volume on the Venture series amps is designed to have most of the volume past 12 o' clock. 2-3pm is a sweet spot so you're running it just fine.

 

[rpavich]

Post gig clip..sorry for the fuzz tone…it was too much.

 

[rpavich]

So...just in case my 1x12 isn't enough (pared with the 15" cab) after the next test gig..would you add a second 15 OR a 2x10? (2x12 cab is pretty big and expensive) I heard "don't mix speaker sizes" and others who say...don't worry about it.
Also...is it a wives tale that a 15" is "all lows and no highs" ? If I had two 15" boxes would that be "all mud"?

 

[dfp]

The combination of VB 112 and 115 got a good write up from a discerning TalkBass gear connoisseur a while back in the Ampeg Venture mega thread. I think you're set for all manner of situations with those cabs.

 

[G Aichele]

Is there any potential problem caused by removing the strap handle of an SVT210-AV? (Apart from no longer having a handle? )

 

[Snibborwocky]

Is there any potential problem caused by removing the strap handle of an SVT210-AV? (Apart from no longer having a handle? )

Not that I can think of. I removed one on mine to let my PF-20T sit level on top without any issues. Just don't lose the handle and screws lol

 

[blr2]

Isn't it affixed with nuts on the inside? If yes, unscrewing it will make the nuts fall inside the cab and cause problems.

 

[Wasnex]

Isn't it affixed with nuts on the inside? If yes, unscrewing it will make the nuts fall inside the cab and cause problems.

Not if they are properly seated T-nuts.

 

[dfp]

Is there any potential problem caused by removing the strap handle of an SVT210-AV? (Apart from no longer having a handle? )

If you wanna be extra sure, put the screws back in their holes once the handle is off, so you aren't leaking extra air on your sealed cab.

I have done it, no loose nuts fell, pretty sure it's t nuts inside

 

[blr2]

Not if they are properly seated T-nuts.

View attachment 7352271

Cool, but could these get loose with time and vibrations?

 

[Wasnex]

Cool, but could these get loose with time and vibrations?

They can definitely fall out. Probably best to reinstall the screws.

I think a better solution is to leave the handle alone and built some sort of adapter or base to go between the amp and cab. Course you might think that is a stupid idea, and for you, you are correct .

 

[blr2]

They can definitely fall out. Probably best to reinstall the screws.

I think a better solution is to leave the handle alone and built some sort of adapter or base to go between the amp and cab. Course you might think that is a stupid idea, and for you, you are correct .

This is a quick and dirty one, made from 4 corks and a ceramic tile.