RH450 with a VT deluxe as a pre-amp

[kmon]

anybody ever run a rusty box or a VT Bass, or any other preamp into the power-amp-in on an RH450?

I was interested in trying this and bypassing the pre on the RH450 itself. Just a tonal experiment.

I *think* I can do this but I'm ignorant on these matters. Any thoughts? Basically I want to use the RH450 as a power amp.

Thanks!!!

[parapentep70]

The short answer is yes, you can. Even they recommend using an RH450 as a slave to another one. It is clear from specs and signal flow diagram.

What I don't know is what level you need to drive the power amp 100%. Specs say max level is +8dBu (some 2V RMS), but I don't know if a more moderate level is enough to take all power from these heads when the master control is at 100%.

[kmon]

yeah I saw the master/slave diagram in the manual and it looked like you could use it as just a power amp.

not sure on the power amp input level...I'll see how it goes...thanks!!!

[CL400Peavey]

I would be concerned about what you use as a preamp. From what I have read, they use a lot of preamping and compression to get their heads to sound like their advertised wattage. A power amp is a power amp. So you are just going to get the actual, lower wattage, power from the amp. You will have to make up for it with similar EQing and compression.

[newbold]

You *can* do it but I recall to this day what it was like to plug a VTBass into a TC Stacatto combo - bypassed, I got my ideal modern tone and then when engaged I got everything I love about Ampeg tone but with a great transparent compressor.

On the other hand it might be amazing beyond words.

[kmon]

Originally Posted by CL400Peavey

I would be concerned about what you use as a preamp. From what I have read, they use a lot of preamping and compression to get their heads to sound like their advertised wattage. A power amp is a power amp. So you are just going to get the actual, lower wattage, power from the amp. You will have to make up for it with similar EQing and compression.

interesting point...yeah I had done some reading on the big to-do about the wattage they were claiming.

I know the head straight up is loud as sh**...be very interested to see what it sounds like without the TC preamp magic

[kmon]

Originally Posted by newbold

You *can* do it but I recall to this day what it was like to plug a VTBass into a TC Stacatto combo - bypassed, I got my ideal modern tone and then when engaged I got everything I love about Ampeg tone but with a great transparent compressor.

On the other hand it might be amazing beyond words.

so you're saying I should try it right??

[parapentep70]

Originally Posted by CL400Peavey

I would be concerned about what you use as a preamp. From what I have read, they use a lot of preamping and compression to get their heads to sound like their advertised wattage. A power amp is a power amp. So you are just going to get the actual, lower wattage, power from the amp. You will have to make up for it with similar EQing and compression.

Apparently all the post-compression (and "Advanced Power Management) comes AFTER the pre_OUT / Poweramp_IN.

A few hours ago I asked in another post for confirmation that the "strong voicing" built into these amps (not the EQ or tube emulation or compression) is also built after the PowerAMP input. I suspect so from some freq. response measurements I did in the past.

EDITED: This is the post and it partially address the original question:

[CL400Peavey]

Originally Posted by kmon

so you're saying I should try it right??

I would look at a Peavey IPR. Lightweight power amp with more than enough power. That would mean you have two amp set ups to use too.

[fraublugher]

I use an MXR M80 DI with my RH450 with and without compression successfully.
It's a wierd new amp , in that the input stage uniquely levels any input you put in but at the same time I can still affect the output at the pre stage.
I don't know the answer to your question.

[kmon]

Originally Posted by parapentep70

Apparently all the post-compression (and "Advanced Power Management) comes AFTER the pre_OUT / Poweramp_IN.

A few hours ago I asked in another post for confirmation that the "strong voicing" built into these amps (not the EQ or tube emulation or compression) is also built after the PowerAMP input. I suspect so from some freq. response measurements I did in the past.

EDITED: This is the post and it partially address the original question:

thank you!! that seems to answer my initial question!!

TB is incredible...

[fraublugher]

However, the modern tone people are complaining isn't available on the RH450 can easily be achieved with a pre-amp [like the MXR M80]

[kmon]

Originally Posted by fraublugher

However, the modern tone people are complaining isn't available on the RH450 can easily be achieved with a pre-amp [like the MXR M80]

do you go straight to the power amp(bypassing the RH450 pre) or do you just plug into the front input like a regular pedal?

if using the preamp do you have the RH450 EQ pretty flat or do you combine that with some M-80 EQing?

I do like the M-80...haven't tried it with the RH though

[parapentep70]

Originally Posted by fraublugher

However, the modern tone people are complaining isn't available on the RH450 can easily be achieved with a pre-amp [like the MXR M80]

I suspect this is not 100% right:

When you set spectracomp and tubetone to zero, all the possible compression (at high volume) should come from the "APM" in the power stage.

The "lack of modern tone" in the 450 (not present in the 750, due to cut of highs) is most probably in the pre section. So you can overcome this with a different pre. I have the 750, so I can be as "modern" as I like when it comes to crystal clear highs.

The part I am not sure is the high pass filtering around 60 or 70 Hz, I suspect it might be in the power section, which is odd but might be very convenient for certain applications.

[JimmyM]

So if you defeat the pre, it doesn't become a 236w RMS amp again?

[CL400Peavey]

Originally Posted by JimmyM

So if you defeat the pre, it doesn't become a 236w RMS amp again?

That is kind of what I was getting at. I havnt read the thread posted above about where the voodoo comes in, pre amp or in the power stage...

[parapentep70]

Originally Posted by JimmyM

So if you defeat the pre, it doesn't become a 236w RMS amp again?

Yes I think so.
This is as relevant,

[CL400Peavey]

Originally Posted by parapentep70

Yes I think so.
This is as relevant,

Please clarify...

A.) Yes it does become just a 236 watt amp

B.) Yes it does keep that voodoo compression

[fraublugher]

Originally Posted by kmon

do you go straight to the power amp(bypassing the RH450 pre) or do you just plug into the front input like a regular pedal?

if using the preamp do you have the RH450 EQ pretty flat or do you combine that with some M-80 EQing?

I do like the M-80...haven't tried it with the RH though

I haven't tried the effects loop yet so plugged in the front.
For a modern tone i crank the highs on the mxr 100% and because I use a jazz bass the mids at 0-10% because the amp is mid heavy.
Also I turn the low mid and mid on the amp to 9 oclockish

[fraublugher]

Originally Posted by parapentep70

The part I am not sure is the high pass filtering around 60 or 70 Hz, I suspect it might be in the power section, which is odd but might be very convenient for certain applications.

I read in the TC literature or maybe here on TB that one of TC's new feature's for digital amps was to eliminate the amps job of amplifying frequencies the human ear can't hear to make the amp more efficient.
Of course I could be wrong ....again.