Head vs Cab

[fuzzspiral]

Hi! I'm planning to switch to tube amps but I need a clarification...
I have an Ampeg svt-410hlf as cab, I'm interested in Ampeg heads (svt classic cl/vr). So, head 300 tubes watts, cab 500w: can the cabinet take the 300watts of the head?
I'm currently using a GK700rbII, so solid state, and no problems but as far as I know tube watts are different in terms of power than the solid state ones. I almost always seen those two ampeg heads with 8x10 cabs...with my 4x10 is there the possibility to spoil the speakers or other things?
Thank you very much

 

[basscooker]

Fill the head with concrete. The air around the tubes will then be in a solid state and the watts will be the same.

 

[basscooker]

In other words you will be fine. No worries about that head and cab, providing impedance is matched.

 

[JimChjones]

Watts is watts, but for those who like distortion tube amps can be pushed a long way beyond their nominal rated power before the sound becomes insufferable. There's a good amount of reserve there, you should be safe enough unless you play at crazy volume.
If you don't play any louder than with current amp then fine.

 

[Wasnex]

Hi! I'm planning to switch to tube amps but I need a clarification...
I have an Ampeg svt-410hlf as cab, I'm interested in Ampeg heads (svt classic cl/vr). So, head 300 tubes watts, cab 500w: can the cabinet take the 300watts of the head?
I'm currently using a GK700rbII, so solid state, and no problems but as far as I know tube watts are different in terms of power than the solid state ones. I almost always seen those two ampeg heads with 8x10 cabs...with my 4x10 is there the possibility to spoil the speakers or other things?
Thank you very much

One difference between tube and solid state is tube amps typically have a lower damping factor. The damping factor relates to how well the amp controls the speaker. This is one reason many people feel tube amps are best with sealed cabs, because sealed cabs tend to be tighter and more controlled on the low end. As you probably know, the 410HLF has some big lows, so you may not like this cab with a tube amp. From what I have seen, many people who like this cab are using high powered solid state output sections, that can exert more control over the low end.

An SVT is rated for 300W at 3%THD, but they typically make about 265W at 5% THD. I believe they can put out transients that are approximately twice their continuous rating.

The 410HLF is rated for 500W RMS and 1000W Peak. These or the cab's thermal limits. But below 100Hz it is very common for drivers to reach their mechanical limits well before they reach their thermal limits. So if you like a lot of heavy bass, some degree of caution is warranted. I.E. it's possible the SVT can push the cab beyond it's limits.

FYI the mechanical limits are determined by the drivers T/S characteristics and the tuning of the cabinet.

 

[Wisebass]

Ciao fuzzspiral

I have an Ampeg svt-410hlf as cab, I'm interested in Ampeg heads (svt classic cl/vr). So, head 300 tubes watts, cab 500w: can the cabinet take the 300watts of the head?

Yep! It was designed to do that.

I almost always seen those two ampeg heads with 8x10 cabs...with my 4x10 is there the possibility to spoil the speakers or other things?

Nope! You won' t spoil the speakers. The only thing you can spoil is the sound.

Compared to a 810 cab your 410 hlf is very bass heavy! The two cabs don 't sound the same.

Whether you like that or not? That' s another question!


may the bass be with you

Wise(b)ass

 

[fuzzspiral]

Allright, thanks to all for the clarifications!

Anyway, since both heads have 2ohm impendance, I could pair another 4ohm cab in the future...but for the moment let's keep the things simple

Excuse me but I'll go grab some concrete at the store now

 

[Paulabass]

The very best way to make sure you are not doing damage to a cab is USE YOUR EARS. If you cab is farting out, you are feeding it too much juice.
The SVT-cl is a great combo with the 410HLF. A very popular pairing.

 

[InhumanResource]

Fill the head with concrete. The air around the tubes will then be in a solid state and the watts will be the same.

Well it's working at Chernobyl so far

 

[Kmonk]

I switched from GK to Ampeg several years ago. One thing to remember is that the SVT CL heads are somewhat counter intuitive in that in order to get the vintage SVT sound, you have to crank the main volume and use the gain to control the volume level.

Ampeg Product Specialist Dino Monoxelos explains it in this video.

 

[fuzzspiral]

So I have the SVT Classic now...and it's simply great. It feels like I'm hearing my bass for the first time!
I have only a couple of doubts (the manual isn't very clear...):

1- Polarity switch. Can I switch its position at any moment, even while playing? Or do the amp has to be in standby mode or completely off, to avoid a damage?
2- After three hours of playing the air from the front fan and panel surface were very hot, I guess it's normal...?
3- Considering I'm using the same pedalboard/effects/connections from before the SVT, is it normal that the hum and buzz increased a lot, compared to the GK700rb? Is it a characteristic of tubes?

Thanks!

 

[Wasnex]

So I have the SVT Classic now...and it's simply great. It feels like I'm hearing my bass for the first time!
I have only a couple of doubts (the manual isn't very clear...):

1- Polarity switch. Can I switch its position at any moment, even while playing? Or do the amp has to be in standby mode or completely off, to avoid a damage?
2- After three hours of playing the air from the front fan and panel surface were very hot, I guess it's normal...?
3- Considering I'm using the same pedalboard/effects/connections from before the SVT, is it normal that the hum and buzz increased a lot, compared to the GK700rb? Is it a characteristic of tubes?

Thanks!

1. You don't need to switch the amp off or into standy to switch the polarity.
2. Yes tube amps do tend to get quite warm. Make sure the bias is set properly and enjoy.
3. In my experience, SVTs do tend to have a bit of extra hum. This is not a characteristic of tubes; it's a characteristic of SVTs. I would say tube amps on average tend to be a bit more noisy than solid state, but not all tube amps are noiser than all solid state. A few of my tubes amps run pretty close to silent.

 

[fuzzspiral]

Thank you for the clarifications!

 

[BassmanPaul]

in actuality the polarity switch can be ignored as in today's world it is obsolete. Your amp should have a three core power cable which grounds the chassis. In the States, back in the day, the AC supply was two core without a ground. The Polarity switch 'grounded' the chassis via a capacitor, to either the line or the neutral. One would switch it to the position of least noise.

 

[catcauphonic]

in actuality the polarity switch can be ignored as in today's world it is obsolete. Your amp should have a three core power cable which grounds the chassis. In the States, back in the day, the AC supply was two core without a ground. The Polarity switch 'grounded' the chassis via a capacitor, to either the line or the neutral. One would switch it to the position of least noise.

Mine definitely changes the tone a bit

 

[JimmyM]

So I have the SVT Classic now...and it's simply great. It feels like I'm hearing my bass for the first time!
I have only a couple of doubts (the manual isn't very clear...):

1- Polarity switch. Can I switch its position at any moment, even while playing? Or do the amp has to be in standby mode or completely off, to avoid a damage?
2- After three hours of playing the air from the front fan and panel surface were very hot, I guess it's normal...?
3- Considering I'm using the same pedalboard/effects/connections from before the SVT, is it normal that the hum and buzz increased a lot, compared to the GK700rb? Is it a characteristic of tubes?

Thanks!

1. You don't need to switch the amp off or into standy to switch the polarity.
2. Yes tube amps do tend to get quite warm. Make sure the bias is set properly and enjoy.
3. In my experience, SVTs do tend to have a bit of extra hum. This is not a characteristic of tubes; it's a characteristic of SVTs. I would say tube amps on average tend to be a bit more noisy than solid state, but not all tube amps are noiser than all solid state. A few of my tubes amps run pretty close to silent.

3. This can sometimes be remedied by finding the tube that's humming the most and replacing it with a new one. But I'm suspecting a miscommunication between the pedals and the SVT.

So Fuzzy, does your amp sound quieter and more in the range of the GK without the pedals? If so, are the GK and SVT plugged into the same circuit as the board or a different one? If not, try plugging them in on the same circuit. If that doesn't work, try each pedal one at a time till you find a culprit. And unplug the other pedals from the power supply if they're not isolated.

If that all doesn't work, report back and/or contact Ampeg CS. We might be able to troubleshoot it as there are a lot of very knowledgeable people here (I'm not one of them but I know a few things about getting pedals to behave), but Hodgy at CS is a master at stuff like this.

 

[Wasnex]

3. This can sometimes be remedied by finding the tube that's humming the most and replacing it with a new one. But I'm suspecting a miscommunication between the pedals and the SVT.

I have tried all sorts of crazy stuff with my vintage SVTs and never successfully eliminated the hum. I believe there are ground loops in the preamp that are beyond my technical abilities to resolve. However, I don't know why I even bother. You can hardly hear the hum over the fan noise .

 

[fuzzspiral]

Thanks @JimmyM.
The SVT has absolutely no problems with the bass plugged in directly, without pedals. Little hum (fan apart) even with the gain cranked up and volume at 3 or 4. I'll try to change positions of the power plugs and try pedals one by one. I've already done with the GK but not with the SVT, let's see. I hope that it's "only" a power supply problem.
Maybe the system power supply (fuzz1) + power supply (fuzz2) + power supply (fuzz3) + power supply (overdrive, DI) + power supply (with 5 pedals chained) is showing its limits...

 

[JimmyM]

Thanks @JimmyM.
The SVT has absolutely no problems with the bass plugged in directly, without pedals. Little hum (fan apart) even with the gain cranked up and volume at 3 or 4.

Cranking the gain up adds tube compression and overdrive from the preamp, which also adds noise that's inherent in compression and dirt, much like your fuzzes. If you want to see how quiet it can go, do the reverse. Turn up master all the way and use gain to control your volume. It'll be clean but then you can see how much noise you add with the gain cranked, then act accordingly. This way also sounds more like the old SVT's with only one volume knob per channel, too.

I'll try to change positions of the power plugs and try pedals one by one. I've already done with the GK but not with the SVT, let's see. I hope that it's "only" a power supply problem.
Maybe the system power supply (fuzz1) + power supply (fuzz2) + power supply (fuzz3) + power supply (overdrive, DI) + power supply (with 5 pedals chained) is showing its limits...

Ya, I don't think it's entirely the gain being cranked by any means. If it's quiet without pedals, it's a pedal miscommunication.

 

[BassmanPaul]

Mine definitely changes the tone a bit

I suggest that you have the amp looked at as the polarity switch should not affect the tone one bit.