Rivera Rockcrusher anyone?

[jape88]

Anyone bought or tried one of these yet? price seems good, youtube clip good, but the all important in the flesh... ummm

http://www.youtube.com/watch?v=bPsQR-T088c" onclick="window.open(this.href);return false;

Ebay sell and spec...

http://cgi.ebay.co.uk/Rivera-RockCrushe ... 35b0209e9b" onclick="window.open(this.href);return false;

[vanhalen5150]

Got one yesterday. Been using a THD hotplate for 3 years. I heard an immediate difference at the -16 and -20 decibel levels. Much better sound IMO. Way less compression with the Rivera. At the lesser attenuated levels there wasnt much difference. Balanced isolated line out, 8/16ohm switchable , built extremely sturdy, almost overkill really. Id like to try the Aracom someday but at the price, can it really be that much better than what Rivera is putting out on this one?
Attenuators arent magic by any means. At the higher settings, you still have to have the speakers kicking enough air to get the same sound at a bigger volume. This is where most people fail in determining what sounds better. You are always limited to what your asking your speakers to do at a small sound level. Your asking a lion to roar at meow levels.

[jape88]

Thanks for the review mate... I've been holding back on one of these or Alex's. Which one of your amps did you run it with out of interest?
When you say 'At the lesser attenuated levels there wasnt much difference.' what do you mean? I would imagine a lot of them are pretty much the same until you start to crank them down?

[vanhalen5150]

Thanks for the review mate... I've been holding back on one of these or Alex's. Which one of your amps did you run it with out of interest?
When you say 'At the lesser attenuated levels there wasnt much difference.' what do you mean? I would imagine a lot of them are pretty much the same until you start to crank them down?

Yeah, thats my point. The Hotplate goes down to -16db and then uses a fine tuner to lower it to room volume. Thats the problem really. Its using an inferior resistor in the knob/pot to lower it those extra steps to room volume, instead of good load resistors as with the louder attenuated volumes in the unit.
The Rivera uses resistive and active loads to take everything down to -20 dbs and then uses a fine tuner at the "studio" selection. I tried it with a Sovtek mig50, Metro 12000 and the big test was my 5150 head dimed through it at 120w. Worked fine. Both 8 and 16 ohm worked well.
The isolated line out, I slaves my 12000 into the power section of the 5150 through the effects return. No noise whatsoever.
Every level was very clean sounding. When you do get down to really low volumes, your speakers tend to be a little on the fizzy side. Every attenuator does this because thats how a speaker behaves with lower power. Plug a 10w amp into a 100w cab and you get the same thing.
Had it apart already to inspect. Big ass ohmite resistors, military type construction. Some wierd circuitry in there I cant ID yet.

[vanhalen5150]

No wait time either. Mine shipped same day.

[caver]

Old thread You still like the Rivera 5150?
I've had a Hotplate (16ohm) for several years but grew tired of it and started playing through a cranked Tiny Terror into a Marshall 4x12. I've been ignoring the Marshalls until I recently finished the 12000 project.

Brad

[harddriver]

The rockcrusher is a high quality unit. This unit far surpasses my THD hotplate and Marshall Power brake for tone quality under attenuation.

[caver]

Thanks for the response.

[Drew3419]

Sorry to bring up an old thread again, but wanted to ask a specific question since I'm looking into getting another attenuator for my MetroAmp-board / transformer 2203 MV. I had a Weber MASS in the past used with another 100W rock amp, and was very disappointed in the sound quality at high attenuation levels.

I'm seriously looking into the Rivera RockCrusher... but also into the Ultimate Attenuator. Those are my top two at the moment. I've been leaning toward the RockCrusher for all the reasons stated above, including price. However, I've heard good things about the Ulimate Attenuator too, and it has a sort-of built in variac (100VAC) plug on the back.

I guess my questions are:

1. Has anybody tried both? Any direct comparisons are welcome. I want to retain tone at high attenuation levels, and also feel.

2. Does the "variac" plug on the Ultimate make any difference to tone and sag, or is it strictly there for amp safety?

3. I have read that the Ultimate Attenuator is really a load box with an internal power amplifier that re-amps the signal. Are there any concerns with this method at all, either related to reliability, or to the quality of that internal amplifier tone or feel-wise?

Thank you for any help you can give!
Drew

[harddriver]

Unless Ultimate changed their design they use a set 32 ohm load, that is a 100% mismatch for your OPT. While technically the amp should handle it I read of a few OPT failures whether or not those were due to the Power tubes failing due high volume use or the ohm load stress on the OPT remains to be seen.

Yes the Ultimate reamps the signal so it is basically a load box reamp setup, not quite a 100% attenuator like the Rivera.

Yes when lowering the input voltage directly will lower the Plate Voltage to your preamp and power tube causing them to distort sooner, 110ACV to 100ACV you may not hear that much difference and the amp will sag slightly. You may like it with your 2203 you may not.

I have not used the Ultimate so I cannot comment on tone. I do own the Rockcrusher it is very well built sounds great and have been very happy with it. It has 8 or 16 ohm impedance setting on the front, you can run two speaker cabinets, has a line out, can be used as a 100% load if needed and is very transparent when compared to my THD and Marshall Powerbrake. You may like the Ultimate by comparison only your ears can tell you that. If you want a true 100% attenuator then the Rivera is it. The Fryette Power station is also an option for you that is getting good initial reviews you may want to check out. Used the Ultimate and Rivera are in the 300 to 400 range. I got both of mine for about 350.

[Drew3419]

Unless Ultimate changed their design they use a set 32 ohm load, that is a 100% mismatch for your OPT. While technically the amp should handle it I read of a few OPT failures whether or not those were due to the Power tubes failing due high volume use or the ohm load stress on the OPT remains to be seen.

Yes the Ultimate reamps the signal so it is basically a load box reamp setup, not quite a 100% attenuator like the Rivera.

Yes when lowering the input voltage directly will lower the Plate Voltage to your preamp and power tube causing them to distort sooner, 110ACV to 100ACV you may not hear that much difference and the amp will sag slightly. You may like it with your 2203 you may not.

I have not used the Ultimate so I cannot comment on tone. I do own the Rockcrusher it is very well built sounds great and have been very happy with it. It has 8 or 16 ohm impedance setting on the front, you can run two speaker cabinets, has a line out, can be used as a 100% load if needed and is very transparent when compared to my THD and Marshall Powerbrake. You may like the Ultimate by comparison only your ears can tell you that. If you want a true 100% attenuator then the Rivera is it. The Fryette Power station is also an option for you that is getting good initial reviews you may want to check out. Used the Ultimate and Rivera are in the 300 to 400 range. I got both of mine for about 350.

Thank you for your detailed reply. I'm amp leaning toward the RockCrusher, and also picking up a standalone variac. I don't want to run my amp in a dangerous situation, but just push it to where I can get sag and saturation at reasonable volumes (house volumes). I'd probably never go below 90-95VAC. At that point, I wonder if I'd need to re-bias my amp, or if my current bias would suffice. Same question with the the heater voltage / cathode stripping. Some people say to worry about it, and some people say it won't be a problem...

[harddriver]

You can check the bias of your power tubes to see where they are running when you lower the AC voltage to the 90 to 95VAC range versus 110ACV. This will give you an idea where the current draw of the tubes is at then, you can either bias your amp to your liking for consistently running at 90-95 VAC or you can bias hot at 110-120VAC then crank your line voltage back to 90-95 VAC whatever you like. It all depends on how much you really want to get into this, it does become addictive.

I run my 68 metroamp at 90 ACV and have adjusted the bias to only run at that VAC, significant cathode stripping has not been an issue and I have run my power tubes for quite some time with no operational issues. If your VAC to your heaters gets significantly below 3.0 V then supposedly cathode stripping might become an issue according to the amp gurus.

The lowered plate voltage when you variac down lessens the stress on the power tubes and as well as the output transformer in addition to distorting sooner when cranking/diming volume on an amp. Most power transformers should be around 450DCV-500DCV on the plates at 110/120ACV depending on the power transformer. When variacing down this will put you at around 400DCV again dependant on the power transformer you have.
Another good reason to do this is most modern production Power tubes don't like to see over 450DCV on the plates because the cathode coatings, materials used and construction methods just aren't as good as the old tubes used to be. I felt I got my money's worth with my Rockcrusher purchases. The Ultimate always seemed a little cheap but that is only my opinion.

[bigsmitty]

I have one and love it play my 74 super lead at bedroom levels sounds real good

[rgorke]

Every thing I have heard from the Alex, now the Scumback DBL, is that it is one of the best out there.

[AJW]

I have an original Alex, and it is markedly better than a HotPlate. I haven't heard the Rockcrusher, but I am pretty happy with the Alex. I have beeen thinking of picking up another (Scumback DBL).