Help me understand this combo amp from GR

[NY2NH]

I'm looking at the description of the AT 210V 800 Combo and I cannot get my head around what it means.

Power
Power head: 350/800W RMS (AES Standard) -
Power cabinet: 400/600W RMS (AES Standard)

Is this saying that if I buy the 800 then I will get 600 watts out of the combo alone? And that if I want the full 800 watts then I will need to add a separate 200 watt 8 ohm cabinet? Or 4 ohm? I have no idea.

Part of what's confusing me is they are using 350/800 interchangeably and I think they are two separate products but I can't really tell from the marketing copy.

Thanks!

 

[bottomzone]

My guess is that 350/800W RMS means 350W RMS/800W peak and 400/600W RMS means 400W RMS/600W peak.

 

[Wasnex]

My guess:

You can order the combo with a One 350 or One 800 head. Ref: ONE – GRBass

The One 350 is rated 350W at 4 ohms and 175W at 8 ohms
The One 800 is rated 800W at 4 ohms and 400W a 8 ohms

Perhaps the 350 comes with speakers rated for 400W and the 800 comes with speakers rated for 600W. This would make sense IMHO. If you look at the AT 210V cabs, you can choose from the regular cab rated at 400W or the + version rated for 600W Ref: AT 210V – GRBass

If the internal speakers are 8 ohms, you need an extension cab to get the full power.

You may be able to choose 4 ohms for the internal speakers. IMHO given the choice, I would choose 8 ohms and get a matching extension cab. If you choose 4 ohms for the internal speaker in the One 800 combo, the amp's power rating exceeds the speaker's power rating by 200W. This is a recipe for potential blown drivers.

FYI, I have an old GK 700RB/112 combo. It's rated 225W at 8 ohms and 380W at 4 ohms. The internal speaker is a single 12" 8 ohm driver.

 

[NY2NH]

Thanks for this reply. This makes sense, sort of. What I think you're saying is I can play the combo alone and it will give me 400W output without there being an issue of the head being too powerful for the speaker. Maybe it somehow steps down in power output if you don't have another speaker connected? I'm a newbie to amps.

Seems like a good amp to use alone for smaller venues and then add in another cab on the off chance I need it.

My guess:

You can order the combo with a One 350 or One 800 head. Ref: ONE – GRBass

The One 350 is rated 350W at 4 ohms and 175W at 8 ohms
The One 800 is rated 800W at 4 ohms and 400W a 8 ohms

Perhaps the 350 comes with speakers rated for 400W and the 800 comes with speakers rated for 600W. This would make sense IMHO. If you look at the AT 210V cabs, you can choose from the regular cab rated at 400W or the + version rated for 600W Ref: AT 210V – GRBass

If the internal speakers are 8 ohms, you need an extension cab to get the full power.

You may be able to choose 4 ohms for the internal speakers. IMHO given the choice, I would choose 8 ohms and get a matching extension cab. If you choose 4 ohms for the internal speaker in the One 800 combo, the amp's power rating exceeds the speaker's power rating by 200W. This is a recipe for potential blown drivers.

FYI, I have an old GK 700RB/112 combo. It's rated 225W at 8 ohms and 380W at 4 ohms. The internal speaker is a single 12" 8 ohm driver.

 

[Wasnex]

Thanks for this reply. This makes sense, sort of. What I think you're saying is I can play the combo alone and it will give me 400W output without there being an issue of the head being too powerful for the speaker. Maybe it somehow steps down in power output if you don't have another speaker connected? I'm a newbie to amps.

Seems like a good amp to use alone for smaller venues and then add in another cab on the off chance I need it.

I go through some of the math to help you understand how solid state amps work.

Solid state amps generally try to hold the voltage constant regardless of the impedance. This results in the power going up as the impedance goes down. Some amps hold the voltage exactly the same, so you get 2X the power when the impedance is cut in half. Some amps cannot hold the voltage at the same level. The voltage may sag a bit, so they may only make about 150% more power when the impedance is cut in half. Some solid state amps have a switch the changes or limits the voltage...so the power may stage exactly the same at two impedance levels.

Example Mesa 800W Subway amps are rated 400W at 8 ohms, 800W at 4 ohms, and 800W at 2 Ohm. They have a switch that must be toggled if the load is less than 4 ohms.

If this combo has an 8 ohm internal speaker the amp will be able to deliver half of the power. So if you get the One 800, the amp can deliver 400W to the internal speaker. If you add a matching extension the amp can deliver 800W.

Here are the formulas: (Click to enlarge)


Voltage at 400W and 8 ohms
V = sq rt(400 x 8) = ~56.57V

Voltage at 800W and 4 ohms
V = sq rt(800 x 4) = ~56.57V

The Power formula is
P = (V^2)/Z

where Z = impedance​

V^2 is 3200.

So P = 3200/Z

So if voltage is held constant, power is determined by the impedance

P = 3200/8 = 400W

P = 3200/4 = 800W

I suggest you don't focus on the power level. Instead focus on how loud the rig can play.

The cabs are rated 103dB 1W/1m

This means with 1W applied, the SPL measured at 1 meter from the cone will be 103dB.

Each time you double the power the SPL goes up 3dB

1W = 103dB
2W = 106dB
4W = 109dB
8W = 112dB
etc

Since you know the usable power is 400W and the sensitivity is 103dB 1W/1m you can also use a formula.

Calculated SPL = [Log(Usable Power) x 10] + 103

Calculated SPL = [Log(400) x10 + 103 = ~129dB

This is pretty darn load.

If you add a matching cab, it will be connected in parallel.
-The impedance is cut in half (8/2 =4 ohms)
-In this case the amp can make double the power (400 x 2 = 800W)
-The power handling doubles (400 x 2 = 800W)...so useable power is 800W.
-Double the cabs and get +3dB. So, the combined sensitivity of both cabs goes is approximately +3dB higher than a single cab, assuming they are stacked together (103 + 3 = 106dB 1W/1m).

Calculated SPL with two matching cabs.
[Log(800) x 10] + 106 = ~135dB

This shows if you add a matching cab and the power doubles, you get +6dB. +3dB is due to the extra sensitivity and +3dB is due to doubling the power

If you add a matching cab and the power stays the same you only get +3dB. The increase comes from the increased sensitivity.


Remember some amps make more power when the impedance goes down, but they do not double the power (check the specs).
If the usable power only increases to 600W (150%)
[Log(600) x 10] + 106 = 133.8dB

 

[cxcxcx]

I go through some of the math to help you understand how solid state amps work.

Thanks for taking the time and making the effort to post this!

 

[NY2NH]

Interesting stuff. Thanks for breaking this down. Seems like an 800W amp head (whether in a combo or separated out) that can run 400W or 800W is very flexible for different scenarios.

 

[agedhorse]

Interesting stuff. Thanks for breaking this down. Seems like an 800W amp head (whether in a combo or separated out) that can run 400W or 800W is very flexible for different scenarios.

Most 800 watt heads operate like this, it's not a unique feature.

 

[seamonkey]

RMS (AES Standard)

AES Standard

I for one, appreciate that they measure to AES Standards.

 

[Jim C]

I for one, appreciate that they measure to AES Standards.

But some of their specs make me wonder:
Frequency response
35 Hz to 22 kHz

 

[Wasnex]

But some of their specs make me wonder:
Frequency response
35 Hz to 22 kHz

Usable frequency response is usually considered -10dB.

 

[HaphAsSard]

Usable frequency response is usually considered -10dB.

Except for Yampeg: if they used -10dB, they'd show ultrasounds at the top, and negative Hertzes at the bottom!

 

[Wasnex]

Except for Yampeg: if they used -10dB, they'd show ultrasounds at the top, and negative Hertzes at the bottom!

AFAIK most companies only relate the term to the low end cutoff.

 

[HaphAsSard]

AFAIK most companies only relate the term to the low end cutoff.
View attachment 5214948

Usably/uhm, usually, yes. There is the odd exception:
https://nas.solutions/db-technologies/bh-15
https://www.dkaudio.fr/sites/default/files/e215_315_415_bd_en_2.pdf
i1212W-point-source-speaker-from-Norton-Audio-

I was keedin' anyway.

 

[agedhorse]

As a point of reference, we provide -3dB, -6dB and -10dB data on all Subway cabinets to aid in "apples to apples" comparisons.

So many of these response specs. are provided without defining the limits used. In these cases it's safest to assume that it's always -10dB or even -20dB without knowing more.

 

[Big Dumb]

I go through some of the math to help you understand how solid state amps work.

Solid state amps generally try to hold the voltage constant regardless of the impedance. This results in the power going up as the impedance goes down. Some amps hold the voltage exactly the same, so you get 2X the power when the impedance is cut in half. Some amps cannot hold the voltage at the same level. The voltage may sag a bit, so they may only make about 150% more power when the impedance is cut in half. Some solid state amps have a switch the changes or limits the voltage...so the power may stage exactly the same at two impedance levels.

Example Mesa 800W Subway amps are rated 400W at 8 ohms, 800W at 4 ohms, and 800W at 2 Ohm. They have a switch that must be toggled if the load is less than 4 ohms.

If this combo has an 8 ohm internal speaker the amp will be able to deliver half of the power. So if you get the One 800, the amp can deliver 400W to the internal speaker. If you add a matching extension the amp can deliver 800W.

Here are the formulas: (Click to enlarge)
View attachment 5213544

Voltage at 400W and 8 ohms
V = sq rt(400 x 8) = ~56.57V

Voltage at 800W and 4 ohms
V = sq rt(800 x 4) = ~56.57V

The Power formula is
P = (V^2)/Z

where Z = impedance​

V^2 is 3200.

So P = 3200/Z

So if voltage is held constant, power is determined by the impedance

P = 3200/8 = 400W

P = 3200/4 = 800W

I suggest you don't focus on the power level. Instead focus on how loud the rig can play.

The cabs are rated 103dB 1W/1m

This means with 1W applied, the SPL measured at 1 meter from the cone will be 103dB.

Each time you double the power the SPL goes up 3dB

1W = 103dB
2W = 106dB
4W = 109dB
8W = 112dB
etc

Since you know the usable power is 400W and the sensitivity is 103dB 1W/1m you can also use a formula.

Calculated SPL = [Log(Usable Power) x 10] + 103

Calculated SPL = [Log(400) x10 + 103 = ~129dB

This is pretty darn load.

If you add a matching cab, it will be connected in parallel.
-The impedance is cut in half (8/2 =4 ohms)
-In this case the amp can make double the power (400 x 2 = 800W)
-The power handling doubles (400 x 2 = 800W)...so useable power is 800W.
-Double the cabs and get +3dB. So, the combined sensitivity of both cabs goes is approximately +3dB higher than a single cab, assuming they are stacked together (103 + 3 = 106dB 1W/1m).

Calculated SPL with two matching cabs.
[Log(800) x 10] + 106 = ~135dB

This shows if you add a matching cab and the power doubles, you get +6dB. +3dB is due to the extra sensitivity and +3dB is due to doubling the power

If you add a matching cab and the power stays the same you only get +3dB. The increase comes from the increased sensitivity.


Remember some amps make more power when the impedance goes down, but they do not double the power (check the specs).
If the usable power only increases to 600W (150%)
[Log(600) x 10] + 106 = 133.8dB

somebody tell the marketing department we shouldn’t need a PHD in physics to decode their advertising. Lol

 

[Relsom]

Dredging up this old thread. I asked GR Bass yesterday about which cab spec is most in line with the 210V 800 Combo. There response was that it is akin to the 210V (non +) 8ohm cab. The manual states that both combos use the 400 watt cab spec and they do not recommend an extension cab with the 350 Watt combo version.