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Chat about Equipment Info
 #81790  by Jon S.
 Sun Jun 13, 2010 7:28 am
I'm getting a preamp (SMS Classic Preamp w/JG Mods) that has just a mono output. I'll probably be feeding it into a Rocktron Velocity 300. This power amp appears to me, from the manual, to allow for either stereo (or dual mono) inputs producing stereo (dual mono) power amp outputs -or- a mono (bridged) input yielding one power amp output; but not one mono input yielding stereo (dual mono) outputs. (Or at least I don't think it allows for the latter - am I missing something?

http://www.rocktron.com/support/manu...0ManualNew.pdf

What's my simplest option to convert the mono preamp out into two dual mono signals (a Y chord?)? And what's my best option (a junction or A-B-Y box?)? Thanks.
 #81792  by Pete B.
 Sun Jun 13, 2010 7:36 am
Brad could probably throw another output jack in his unit on request.
Looks like the amp your looking at doesn't have it, but ime, alot of power amps have a line-out right next to the input of each channel.
On the MosValve 962 for example, I run the mono signal to the input of Channel A, then Channel A line-out to the input of Channel B. Then I run the Channel A and B Speaker outs to the speakers that in my case may or may not be in the same cab.

Image
Last edited by Pete B. on Mon Jun 14, 2010 9:06 am, edited 1 time in total.
 #81796  by tigerstrat
 Sun Jun 13, 2010 10:55 am
Image

sure looks like it has 2 outputs for each channel. Why do you need two of the same mono preamp output to input to the power amp?

IOW, if you are looking to run multiple cabs w/ bridged power, you are covered; the only reason I see to want dual preamp mono outs would be to run dual power amps, each in bridged mode, but you didn't mention anything like that. I think you already have what you are looking for.
Last edited by tigerstrat on Sun Jun 13, 2010 1:41 pm, edited 1 time in total.
 #81798  by Jon S.
 Sun Jun 13, 2010 12:01 pm
Because the pix you're looking are at not the power amp I'll be using (re-read the thread! :D ).

In any event, it's now a non-issue as Brad has told me he can add a second mono out to my Classic Preamp that's in progress now!!! :cool:
 #81802  by tigerstrat
 Sun Jun 13, 2010 1:46 pm
Jon S. wrote:Because the pix you're looking are at not the power amp I'll be using (re-read the thread! :D ).
Jon S. wrote:I'll probably be feeding it into a Rocktron Velocity 300.
tigerstrat wrote:Image
That's not it ?
 #81808  by Jon S.
 Sun Jun 13, 2010 3:41 pm
Oh, I see the cause of the confusion now. The pics are of the OLD, discontinued, 2U Velocity 300. In my OP, I provide a link to pics and info. on the NEW, 1U Velocity 300.

Whew - another mystery solved. :smile:
 #81811  by tigerstrat
 Sun Jun 13, 2010 6:24 pm
I now realize this is a pic of an older, larger model, but the dual outs for each channel are the same.

Here's from the current user's manual:
When switched to “BRIDGED” the Velocity 300 operates as a mono unit with increased output
power (Channel 2 becomes inoperable in this condition).
In the "BRIDGED" position the LED
will be "ON". In the “STEREO” position the unit operates as a normal stereo amplifier with 150
watts per channel or side.
So the question remains- if channel 2 becomes inoperable, where will the 2nd preamp output go?
 #81815  by Jon S.
 Sun Jun 13, 2010 7:16 pm
I don't see the confusion. Per the RV300 manual, In bridged, it's mono in, mono out. In stereo, it's stereo (or dual mono) in, stereo (or dual mono) out. This certainly seems straightforward to me. In any event, it's now a non-issue as Brad will be wiring my unit to have a dual mono out to feed the power amp's stereo (dual mono) in. I.e., I'll be able now to run my unit in stereo - I'm covered! 8)

EDIT: Thought I add, among the reasons I'm into going stereo is I'm going to run each channel, at 75W per side, into it's own individual 8 ohm speaker in a single 2X12 cab. There are benefits to this approach I like.
 #81816  by tigerstrat
 Sun Jun 13, 2010 8:07 pm
I was under the impression from your opening post that you wanted to run one mono input yielding dual mono outputs, and I figured you just switch it to BRIDGED and plug into Ch. A. But from your last post I see that you want to run both channels, or stereo mode. Mystery solved again.
 #81819  by Jon S.
 Mon Jun 14, 2010 3:17 am
The last part is correct. On the first part, my reading of the RV300 manual is that it lacks the capability to plug into just one channel and run dual mono outs (Brad reached a similar conclusion from his reading of it). I'd be more than happy to run one mono in and dual mono outs - if so, I would not need the dual outs I'll be getting now on my SMS Classic Preamp - but the new RV300 is not configured to support this.

Again, if there's something in the manual you can see that I've missed that's relevant, by all means, please let me know. I'm more than happy to be wrong on my analysis as it would simplify life for me and others.
 #81843  by Pete B.
 Mon Jun 14, 2010 9:27 am
Jon S. wrote:The last part is correct. On the first part, my reading of the RV300 manual is that it lacks the capability to plug into just one channel and run dual mono outs (Brad reached a similar conclusion from his reading of it). I'd be more than happy to run one mono in and dual mono outs - if so, I would not need the dual outs I'll be getting now on my SMS Classic Preamp - but the new RV300 is not configured to support this.

Again, if there's something in the manual you can see that I've missed that's relevant, by all means, please let me know. I'm more than happy to be wrong on my analysis as it would simplify life for me and others.
Re: The Manual:
On page 12 it shows a mono input going into channel 1, then running out of the dual-mono channel-1 outputs.
Isn't this what you want?
Given two 8ohm speakers in Parallel... Channel A delivers 75W per speaker UnBridged, or 150W per speaker Bridged.
fwiw, On this type of stuff I usually just go buy one using a card, and return/send-back if I don't like it for whatever reason.
 #81857  by Jon S.
 Mon Jun 14, 2010 4:57 pm
[I'm so tired now I even typed this same reply out a minute ago, hit what I thought would submit it, and ended up losing my post and having to start over. :cry: ]

Pete, I'm sorry, man - you're absolutely right. It's academic at this point anyway, though, as what I've decided to do is run individual mono signals from the SMS Classic Preamp (which Brad, with my deep appreciation, will be wiring with dual outputs) separately into each side of the Velocity 300 power amp set in stereo, and then each side of the power amp will run out into its own, independent, 8 ohm 12" speaker. This will give me max versatility and tonal options (one speaker will be a JBL K120, the other a Jensen Neo 12-100).

I'll go and splash some water on my face now. :oops: :smile: