TC Electronic RH750 ???!??

[Eublet]

I would think that using the FET preamp channel of the Genz Benz ShuttleMax 9.2 (or 12.0 or 6.0) could fit that tonal bill as well.

I would agree also, but those heads don't have the trully flat voicing in the preamp the way the F500 does. They tend to start out brighter and more articulate IME, but in the end that might be more what a player wants. The F500 is just a good choice to me for the feature set. 4 bands, 2 semi-para mids, and the oh-so-wonderful VLE control for pulling out as much of that top end sheen as you want. Also, the VPF really dials in that modern tone quickly for folks who want it. Just a marvelous design. I so wish they'd make a LM4 with those semi-para mid controls and a mute switch. I'd be all over it.

 

[Jazzdogg]

I find everything about the F500 enticing, except the fact that I'd have to buy two if I wanted to drive multiple cabs with a combined impedance of less than 4 Ohms.

My B1500 and iAmp800 tolerate a 2 Ohm load; I'm hesitant to buy a new head that lacks the potential to become my one and only.

My search continues for a powerful, lightweight, contender that can handle a 2 Ohm load. Perhaps an EA iAmpPro, or Carvin B2000...

 

[OhulahanBass]

Gas is brewing.

 

[peledog]

It looks like TC hasn't revised the Rh450 pages on their website yet but the Rh450 specs are included in the new "Active Power Management" PDF on the Manuals page for the RH750.
The table in Jazzdogs post #827 gives the important information. The bottom line is that the RH450 has a 450 watt power module before the APM so TC did not LIE in saying it was a450 watt amp and the RH450 is not just a 250 watt amp with compression and limiting as some have said.

Lol. O.K.

But this is for the RH750. Carry on.

 

[Vic]

My B1500 and iAmp800 tolerate a 2 Ohm load; I'm hesitant to buy a new head that lacks the potential to become my one and only.
...
My search continues for a powerful, lightweight, contender that can handle a 2 Ohm load. Perhaps an EA iAmpPro, or Carvin B2000...

FWIW, I had huge reliability problems running my iAmp800 at 2 ohms... honestly, even 4 ohms when kinda' pushing it.

 

[mtb777]

My Carvin Ohm Load iPhone App sez 2 loads at 11ohms and 1 at 12 ohms (because they don't have a decimal point) so I couldn't input 11.54 ohms...anyway, came out to 3.77 ohms load.

 

[BurningSkies]

It looks like TC hasn't revised the Rh450 pages on their website yet but the Rh450 specs are included in the new "Active Power Management" PDF on the Manuals page for the RH750.
The table in Jazzdogs post #827 gives the important information. The bottom line is that the RH450 has a 450 watt power module before the APM so TC did not LIE in saying it was a450 watt amp and the RH450 is not just a 250 watt amp with compression and limiting as some have said.

The 450w can never be realized for output, AND it's a 'burst RMS' rate, which beyond not making sense is basically paramount to claiming your amp based upon peak wattage. Not to get in the the same old argument, but just because there's a 450w buried in it doesn't make it a 450w amp.

At least they're now being up slightly less deceptive about it.

 

[Munjibunga]

The 450w can never be realized for output, AND it's a 'burst RMS' rate, which beyond not making sense is basically paramount to claiming your amp based upon peak wattage. Not to get in the the same old argument, but just because there's a 450w buried in it doesn't make it a 450w amp.

At least they're now being up slightly less deceptive about it.

Seems like I've heard that somewhere before. Isn't that about a different amp?

 

[JimmyM]

Seems like I've heard that somewhere before. Isn't that about a different amp?

Same deal with all of them.

 

[vin*tone]

The 450w can never be realized for output, AND it's a 'burst RMS' rate, which beyond not making sense is basically paramount to claiming your amp based upon peak wattage. Not to get in the the same old argument, but just because there's a 450w buried in it doesn't make it a 450w amp.

At least they're now being up slightly less deceptive about it.

Well no. They are making a distinction between Peak and burst. The burst figures in the chart are quoted at RMS. ie. if the RMS is 450 watts then the sin wave peak is mathematically higher than that.

I'm no amp tech but I think that's what they are saying.

 

[Thombas]

If you want that clear piano like tone, get an F500.

...or a piano...

 

[Musicman20]

I have re-read the factsheet for the APM, im still confused how the 450 and 750 have the same long term RMS wattage, when the other ratings differ significantly across that table they produced.

I understand how the APM works a little more now. It would be interesting to see what happens with APM disengaged. Personally, it makes 'sense' how they made the amps react, and after hearing how nasty a solid-state clipping sounds, im not surprised they tried something a little different.

I still have no regrets going for a TC setup.

 

[parapentep70]

I have re-read the factsheet for the APM, im still confused how the 450 and 750 have the same long term RMS wattage, when the other ratings differ significantly across that table they produced.

I understand how the APM works a little more now. It would be interesting to see what happens with APM disengaged. Personally, it makes 'sense' how they made the amps react, and after hearing how nasty a solid-state clipping sounds, im not surprised they tried something a little different.

I still have no regrets going for a TC setup.

After reading all their claims now I guess (my guess is driven by certain hint mentioned in the forum by the designer): Different power modules, same power supply and if my guess is correct, same EMI / RFI issues to be solved at reasonable cost by limiting long-term power.

I am happy with the RH750, but I am building custom cabs for it BASED ON SPECS. If I had known beforehand the details. I would've done things slightly differently.

I have not actually played loud with the amp, still building my cabs (two 1x15 with good mids).

 

[DonovanBankhead]

I am happy with the RH750, but I am building custom cabs for it BASED ON SPECS. If I had known beforehand the details. I would've done things slightly differently.

If you would have based them off of the actual recent specs, I think you would make a mistake.

Anyone want to try this and tell me what happens?

• Take a 300W 4-ohm cab and run the RH450/RH750 camp into it full tilt.

• Take pictures of said cab exploding

 

[BurningSkies]

If you would have based them off of the actual recent specs, I think you would make a mistake.

Anyone want to try this and tell me what happens?

[*]Take a 300W 4-ohm cab and run the RH450/RH750 camp into it full tilt.



[*]Take pictures of said cab exploding

Is that 300w thermal power handling or 300w displacement limited power handling?

 

[parapentep70]

Is that 300w thermal power handling or 300w displacement limited power handling?

In my case the end result is not that bad. I had to decide between cabs based on the Eminence Kappalite 3015LF, 3015 (not LF) and Beyma 15P80ND (specs in between but higher thermal power).

3015 is the right choice for my 2x1x15 rig: I am not displacement limited at some 500...600W peak power per cab at the worst frequency (35 Hz) with some margin at some higher freq (60 Hz or so, cannot remember). This is in line to what the RH750 can deliver for very short bursts. Eficciency at low freqs is 2 dBs better than using the two 3015 LF. My single mid/high horn driver can cope with the 2 woofers with some margin (he can generate almost 130dB continuously from 1200 Hz!)

So a sub-optimum cab for the head. Yes.

But I was also considering a good pre and a good power amp. I considered 3015LF with some 1000...1500W power, or even better the Beyma at some 2000....2500 (it has more thermal power handling). Then I thought... is this too much? What about a simpler head putting just 750 W RMS and going to the lower rating, higher efficiency 3015? I tried the RH750 and I liked equalization, size and features. But when I discovered the real power numbers... I think the rig is very good, but I don't think I have the perfect head for the custom made cabinets.

I saw in another thread what could be the ideal head for Fearful cabs, I would never mention RH750 or tube amps with less than 300...400W as ideal to match Fearful encloures. These heads will require more cab efficiency, and at these power levels none needs the killer displacement limits of the 3015LF at 8 ohms. In my opinion a "Barefaced-like" cab (based on 3015) is a much better option at modest power levels.

I want to finish my cabs and PLAY BASS! I made a lot of progress this weekend bt I will not be able to do much for a week or 2.

 

[BurningSkies]

In my case the end result is not that bad. I had to decide between cabs based on the Eminence Kappalite 3015LF, 3015 (not LF) and Beyma 15P80ND (specs in between but higher thermal power).

3015 is the right choice for my 2x1x15 rig: I am not displacement limited at some 500...600W peak power per cab at the worst frequency (35 Hz) with some margin at some higher freq (60 Hz or so, cannot remember). This is in line to what the RH750 can deliver for very short bursts. Eficciency at low freqs is 2 dBs better than using the two 3015 LF. My single mid/high horn driver can cope with the 2 woofers with some margin (he can generate almost 130dB continuously from 1200 Hz!)

So a sub-optimum cab for the head. Yes.

But I was also considering a good pre and a good power amp. I considered 3015LF with some 1000...1500W power, or even better the Beyma at some 2000....2500 (it has more thermal power handling). Then I thought... is this too much? What about a simpler head putting just 750 W RMS and going to the lower rating, higher efficiency 3015? I tried the RH750 and I liked equalization, size and features. But when I discovered the real power numbers... I think the rig is very good, but I don't think I have the perfect head for the custom made cabinets.

I saw in another thread what could be the ideal head for Fearful cabs, I would never mention RH750 or tube amps with less than 300...400W as ideal to match Fearful encloures. These heads will require more cab efficiency, and at these power levels none needs the killer displacement limits of the 3015LF at 8 ohms. In my opinion a "Barefaced-like" cab (based on 3015) is a much better option at modest power levels.

I want to finish my cabs and PLAY BASS! I made a lot of progress this weekend bt I will not be able to do much for a week or 2.

I would think that if the RH750 fit a tonal profile you enjoy, then it may work for your setup. I think anyone trying to say that your cab is going to get near its displacement limits OR its thermal limit is questionable at best, even if a single 3015 could be had in a 4 ohm version. I’d like to see what BGM makes of their power ratings as newly listed, since they’re listing both amps with a ‘long term RMS’ of 236w, which would be the ceiling for the compression/limiting scheme. In the 450, the amp never exceeded that even at ‘burst rate’, though the chart suggests that it could hit as high as 264w (hark, look at the waveform shown above the nice little number chart which shows nothing hitting higher than 236w). Either way, no matter what some users say, I don’t think those who are using low wattage cabs probably have much to worry about. Just because it sounds loud doesn’t mean that your amp is showing the wattage that the perceived volume is suggesting. Your cab doesn’t perceive anything…it reacts to actual input. The amp may push you slightly closer to the thermal limits than a standard amp would, as the denser ‘energy’ also means less ‘resting’ time between what passes for the crests the amp puts out, and a bit less cooling time.

The good news is that you can run 3 3015’s if you want…you’ve got a minimum load of 2.66 ohms… if you can reach that high to adjust your settings and plug in. If you’re looking for an amp that can use the 3015 to closer to its limits you may want to wait for the RH2000.

 

[parapentep70]

I would think that if the RH750 ........................................
................
The good news is that you can run 3 3015’s if you want…you’ve got a minimum load of 2.66 ohms… if you can reach that high to adjust your settings and plug in. If you’re looking for an amp that can use the 3015 to closer to its limits you may want to wait for the RH2000.

Yes, I know my cabs will take any power the RH750 can deliver, and I have the 2 dB advantage over a design based on the 3015LF.

But you brought a very interesting point for RH450 - 750 users that I do NOT think it has been mentioned. And it goes well with what many people say "they hear".

Apparently part of the limitation is in the power supply. Look at "sustained RMS" power numbers at 4 ohms and 8 ohms. Apparently "sustained RMS power" is very close. Exactly the same in the case of the RS750. So I think there is something in the power supply system (current sensing) telling something in the signal chain to limit gain... something similar to what happened in vintage (old or not) tube amps with very "weak" rectifiers (most users said a tube-rectifier amp "sounds more tubey" than the same with SS rectifier).

I think this "tubey" way to limit power both sounds "warm" or "tubey" and also very loud to the ear.

This goes well with the experience by many users: "With 4 ohms it sounds as loud as other 500W amps, with just one cab, at 8 ohms it sounds much louder than the other 500W". or "It seems to sound equally loud with 8 ohms or 4 ohms versions of the same cab"

To me the bottom line is that the incremental power by adding one extra cab is going to be small. I should be "loud enough", if I wanted more power I´d add a proper power amp or upgrade my RH750 to something else.

 

[BurningSkies]

Yes, I know my cabs will take any power the RH750 can deliver, and I have the 2 dB advantage over a design based on the 3015LF.

But you brought a very interesting point for RH450 - 750 users that I do NOT think it has been mentioned. And it goes well with what many people say "they hear".

Apparently part of the limitation is in the power supply. Look at "sustained RMS" power numbers at 4 ohms and 8 ohms. Apparently "sustained RMS power" is very close. Exactly the same in the case of the RS750. So I think there is something in the power supply system (current sensing) telling something in the signal chain to limit gain... something similar to what happened in vintage (old or not) tube amps with very "weak" rectifiers (most users said a tube-rectifier amp "sounds more tubey" than the same with SS rectifier).

I think this "tubey" way to limit power both sounds "warm" or "tubey" and also very loud to the ear.

This goes well with the experience by many users: "With 4 ohms it sounds as loud as other 500W amps, with just one cab, at 8 ohms it sounds much louder than the other 500W". or "It seems to sound equally loud with 8 ohms or 4 ohms versions of the same cab"

To me the bottom line is that the incremental power by adding one extra cab is going to be small. I should be "loud enough", if I wanted more power I´d add a proper power amp or upgrade my RH750 to something else.

I did notice that the usual variance between 4 and 8 ohm loads is different from what we expect, but then, since we're in the realm of creative power management, I think we can assume that nothing is really functioning by way of traditional relationships.

Of course, by adding an additional cab, you're getting additional speaker real estate, which is a more effective way for increased volume rather than increased wattage due to impedance changes.

Their little chart also puts to sleep any sense that they're cabs magically work better with their heads than others allowing for 3x8ohm cabs on an amp that runs down to 4ohms. Their amps actually run down to 2.66ohms.

 

[Hankenstein]

Picked up a used RH750 last week. Gigged it twice this week in two different settings (R&B band and straight-ahead jazz) paired with Epifani D.I.S.T. 210 cab and my Fodera.

It performed well. I'm pretty happy with the sound and power. I had trouble getting a good slap sound but I'm not familiar with the settings yet. I'm confident I'll be able to correct that.