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Author Topic: I don't know where to begin  (Read 1539 times)

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skarkowtsky

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Re: I don't know where to begin
« Reply #15 on: Time Format »

Thanks for the replies guys. Clock radio was an exaggeration, it just sounds muffled and flat, but not really “thin” like a 3” radio speaker.

I just tested through a friends Celestion G-12 50AVT in a Marshall combo (bypassed) with the rear mounted and removed. I couldn’t push it hard with the Carvin in bridged mode as it’s only a 4ohm speaker. Not the greatest speaker, but I think I detected a brighter tone.

I then tested the Redback in the MojoTone cabinet with the Carvin set to stereo, 8ohm, just using Channel 1. The tone sounded the same as the previous tests, no improvement.

I’m pretty convinced it’s the Redback. I also think my ears will have to adjust to the Carvin, which will never be the Boogie. But, I think with a brighter speaker and EQing on the Rane, I can get a tone to be proud of.

One thing I noticed in the MojoTone cabinet is that the terminal clips on the lead wires are very dull, when I scratched them it brought out a shine underneath. Maybe oxidation from sitting in a parts bin at their shop? Could that affect tone? I tried DeOxit, but it wouldn’t budge. I might need to try steel wool or just replace those terminals.

« Last Edit: Time Format by skarkowtsky »
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rnolan

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Re: I don't know where to begin
« Reply #16 on: Time Format »

Hey John, you shouldn't use bridge mode into a 4 ohm speaker, you could easily damage the output transformers (as the manual says).  What you should have done is try you mates 4 ohm speaker on each channel in stereo mode and set the speaker switch(s) on the Carvin to 4 ohm.  Also you should try each channel in stereo mode (with 8 ohm selected), just put it in standby while you change over the leads.  As said before, just to check both channels are the same.  When you test channel 2 in stereo mode it will use the other EHX phase splitter (which isn't used in bridge mode) as who knows, maybe one EHX is faulty  :dunno: or even one of the power tubes. You could try deOxit and use a washing up scourer, If you use steel wool use 000 or 0000 grade or you risk taking off the coating.  Oxidization isn't good although a little less an issue at speaker currents (watts) compared to input signals (millivolts/volts).  Unusual to have those type of connectors on rocknroll gear, they are more typically used in hifi stuff.  If you replace them, change the connectors to Speakons 2 pole (male plug and female socket https://www.neutrik.com/en/product/nl2fx) they don't have to be soldered (although you can solder them as well as screw).

Again, are you using nice thick speaker cable? hopefully not that thin crap people use in there home stereos or cars
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skarkowtsky

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Re: I don't know where to begin
« Reply #17 on: Time Format »

Oops!!

I played for about a minute or two at a bedroom volume and just above. I hope that wasn’t enough to damage the Output Transformer!

I’m using a Rapco 16 gauge, 6 foot long speaker cable from the amp to the cabinet with 1/4 inch Neutrik male plugs. The cabinet has a Switchcraft 1/4 inch female, and is internally wired from the factory with 18 gauge wire.

Attached is a photo of the connectors I was referring to earlier, from cabinet jack to speaker terminals

John
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Harley Hexxe

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Re: I don't know where to begin
« Reply #18 on: Time Format »

Hey John,

    For cleaning up dull connectors like that, I would just rub it gently with a pencil eraser, just don't scrub it with that because as Richard said, it could remove the coating.

    Well it seems like you've solved the tone issue. Muffled and flat makes a bit more sense than the clock radio. When I have speakers out of phase, I describe the sound like it's coming out of the cardboard tube of a roll of paper towels. Yes, muffled and flat on a Redback would probably be because you aren't driving it hard enough to let it open up. I won't have a lot of high end and it does have enhanced lows so most of what you'll hear out of that will be low midrange tones. I guess Celestion designed it that way so it doesn't make your eardrums bleed at 150 watts. That speaker might sound good on my 400PS, and it could just be able to handle one of my speaker outputs, but honestly, I would use a pair of them on that amp just to be safe not to blow them.

    The Celestion F12M-150 maybe the kind of sound you are looking for.

Harley 8)
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skarkowtsky

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Re: I don't know where to begin
« Reply #19 on: Time Format »

Thanks, Harley.

I just listened to an in-depth review of 4 Celestion's, one of which was a Redback. Wet and dry signals, though I was paying attention to the dry signals. The Celestion Vintage 30 (60w) is what I'm striving for, though the Alnico Cream (90w) was very close.

Since I'm playing at bedroom levels, could I in theory use either of these without destroying them? I'm thinking The 100w Carvin driving the 60w at bedroom levels might actually be just right to make it sound great at lower volumes.

Thoughts?

I’m not in a position to sell the 1x12 for a 2x12 to fit with two low wattage speakers at the moment, unfortunately.
« Last Edit: Time Format by skarkowtsky »
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Harley Hexxe

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Re: I don't know where to begin
« Reply #20 on: Time Format »

Hey John,

    That's a pretty tricky call. In theory, it should be okay, but my understanding is that it's not so much the power that could destroy a speaker, but the distortion. I don't know if it's true, but I've been told that you could drive 1000 watts into a 10 watt speaker as long as it's clean power. The slightest bit of distortion though, will fry the voice coil. This could be what might end up being a costly mistake for you by using a 60 watt speaker with 100 watts of power amp. I don't know enough about this to advise you to a safe course of action.

    Personally speaking, when it comes to choosing speakers for any amplifier, I always go the opposite direction. I always look to double the power handling of the speakers for the amplifier they are going to. That's why I said I would try a pair of the redbacks into my 400PS. Each speaker output jack is 145 Watts RMS on that amp, and that's pretty close to the limit of that speaker. A pair should be able to handle that wattage safely, even though it peaks at 980 watts.

    The 60 Watt Celestion you are thinking of, is that one of the higher powered Vintage 30 speakers? It seems Celestion makes these voiced speakers in different power ranges.  As far as what you are thinking about doing, I think Marshall JMP would be the one to ask about the risks of this kind of setup.

    MJMP, would you care to shed a bit of light on this subject please?

Harley 8)

P.S. The speaker I suggested supposedly does that sound but at the level you're looking at.
« Last Edit: Time Format by Harley Hexxe »
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skarkowtsky

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Re: I don't know where to begin
« Reply #21 on: Time Format »

Yes, I also err on the side of caution and chose the 150w Redback for the 100w Carvin. I should've just bought the 200w Black Shadow!!

However, I did some more testing tonight. Channel 2 in stereo with matched impedance to the Redback sounded just as lackluster as Channel 1 in bridged and stereo. I went back to bridged and started creating new tones. Everything sounded muffled until I drove the pre-amp tubes up past 7.5. Wasn't crystal clear, but better. However, I really want that tight Marshall tone you achieve at lower gain settings (think AC/DC), but my tone is more muffled at the lower settings.

I also think I leveraged the characteristics of the Redback by pushing the pre-amp tubes as saturation and brighter tone emerged.

• OD1 7.5
• OD2 7.5
• Master 7
• Bass 4
• Mids scooped -4 (anything higher and it starts getting honky)
• Treble 6 (anything higher and it sounds ice picky)
• Presence 4 (anything higher and it starts getting ice picky)

With a dry signal, this got me halfway there. Then I re-introduced the Lexicon MP-1 PCM 60 reverb setting and boosted the 80hz to +8 and 100hz to +3 on the Rane EQ and achieved a MONSTROUS low end riding under a nice, bright growl. However, pinch harmonics were clipping, breaking up and ice picky–something I never experienced with the Black Shadow and EMGs.

Maybe this is this best tone I'll get with the Redback, or maybe the MP-1 really does need some service. I feel like I've seen and heard amazing MP-1 settings well past the values I listed above. Even some of the factory settings sound mid-rangy and muffled. I doubt ADA intended those presets to sound like that.

I feel like my unit only shines when settings are halfway through their bands. Or, maybe the low end of the Redback is accentuating things in an unfavorable way.

The simplest way to put it: all this expensive gear sounds like a combo practice amp, unless I boost bass and scoop mids. I feel like I'm not enjoying the full range and capabilities of this preamp.

I'm sort of out of tests. Not really sure what to do now. New speaker, cabinet or power amp? MP-1 service? Once I get the EMGs back in, I'm hoping to hear a difference!

Here's a question for you guys. With a dry signal, MP-1 to power amp, do you hear clarity from bass through treble? Do pinch harmonics sing and ring out, or are they anemic and break up quickly? I only get the MP-1 to sound full and saturated when I soak it with effects. I just want to know if that's normal for this preamp.
« Last Edit: Time Format by skarkowtsky »
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Harley Hexxe

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Re: I don't know where to begin
« Reply #22 on: Time Format »

Hey John,

     With My MP-1, I get plenty of clarity, but then again, I don't have a Carvin power amp to answer that question with. I have ADA and a couple of Peavey Classic 50/50 power amps to run through. Also, I'm not running anything like that through a single speaker. I use my ADA split stack cabs that are loaded with 50 watt black back Celestions, that they came with.

    Pinched harmonics sound more like bird calls at cleaner settings, but jump out with higher gain settings.

Harley 8)
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skarkowtsky

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Re: I don't know where to begin
« Reply #23 on: Time Format »

Pinch harmonics sounds weak at high gain settings for me. They actually always have on my MP-1, unless I color it with reverb. Then they leap off the fretboard. So, maybe there is also something off with my MP-1.

My Boogie, now that thing screamed for days without any effects.
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rnolan

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Re: I don't know where to begin
« Reply #24 on: Time Format »

You can run a less wattage speaker on  bigger amps e.g. 100w into 60w speaker but you have to be careful.  Where the distortion thing comes in is that distorted signals like we use on guitar are quite compressed as in full volume all the time.  With cleaner more dynamic sounds the speaker just get peaks which they will handle (remember the confusing peak music power vs watts RMS)  So RMS (root mean square) is a continuous measure so a 50 watt rms amp into a 50watt rms speaker is fine at full continuous level (which is unusual although more possible with very distorted guitar).

John, if you went with a 60 watt speaker, just use one channel of the amp so 50w > 60w sp.  50 watts is heaps when you turn it up.  You don't have to run the amp in bridge mode, it's quite happy just driving one channel.

I always had heaps of pinch harmonics with MP-1 (with or without Fxs), you do have to be careful where on the string you pick them though.  If the pinch sets a harmonic which has a node (dead spot) over the PU you've selected, you won't hear it as the harmonic splits the string up into multiple high and low points (governed by the note/harmonic) at the low point there is nothing for the PU to pick up.  This is why they seem to work better using the bridge PU as some middle PUs and neck PUs are under the dead spot (again depending on the note/harmonic).  E.g. if you play a 12th fret harmonic it splits the string in 2, the light touch over the 12th fret sets a dead spot with peaks then half way between the nut and 12th fret and half way between 12th fret and bridge, a PU under the 12th fret (if you place one there) would hear nothing.  When you do a pinch harmonic, it sets a dead spot where you pinched/picked it.
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skarkowtsky

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Re: I don't know where to begin
« Reply #25 on: Time Format »

I’m asking these questions to pit my MP-1 against some of yours. I have no issue with the pinch harmonic technique, hit them every time. But, I’ve never been able to squeeze one out of the dry MP-1. Prior to all the speaker issues, I suspected my unit might need service and I was preparing to send it to MarshallJMP. I got sidetracked with the speaker, but I think it’s time to also ship the MP-1 off as well.
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skarkowtsky

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Re: I don't know where to begin
« Reply #26 on: Time Format »

I spoke with the tech who serviced the Carvin. He biased it right in the middle, neither cold or hot. He agrees I changed too much at the same time. He also likes the 60w Creambacks, wasn't convinced I'd necessarily fry the speaker with the 100w Carvin at bedroom volumes. He said he could convert the amp to accept 6l6 if I wanted to. Remember, I have the older Tube 100, not the TS100, and it only accepts EL-34s. He also shared that he's never been a fan of anything Carvin has made. I asked him about the mono Peavey Classic series, he said it would be a good option should I want to change the power section entirely. I like that they are self-biasing like Mesa.

I might also look into the stereo 60/60, then swap the Redback for two 90w Creambacks in a 2x12 I can wire in stereo. I won't get the full effect, but will get fatter chorus and some ping pong delay. I also think I'm robbing the power section by using it at low volumes in bridged mode. I'm definitely not driving that Redback whether I like the tone or not.

Next step is to put the EMGs back in and listen to what happens.
« Last Edit: Time Format by skarkowtsky »
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Harley Hexxe

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Re: I don't know where to begin
« Reply #27 on: Time Format »

I’m asking these questions to pit my MP-1 against some of yours. I have no issue with the pinch harmonic technique, hit them every time. But, I’ve never been able to squeeze one out of the dry MP-1. Prior to all the speaker issues, I suspected my unit might need service and I was preparing to send it to MarshallJMP. I got sidetracked with the speaker, but I think it’s time to also ship the MP-1 off as well.

Even at a higher gain preset?
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Harley Hexxe

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Re: I don't know where to begin
« Reply #28 on: Time Format »

I spoke with the tech who serviced the Carvin. He biased it right in the middle, neither cold or hot. He agrees I changed too much at the same time. He also likes the 60w Creambacks, wasn't convinced I'd necessarily fry the speaker with the 100w Carvin at bedroom volumes. He said he could convert the amp to accept 6l6 if I wanted to. Remember, I have the older Tube 100, not the TS100, and it only accepts EL-34s. He also shared that he's never been a fan of anything Carvin has made. I asked him about the mono Peavey Classic series, he said it would be a good option should I want to change the power section entirely. I like that they are self-biasing like Mesa.

I might also look into the stereo 60/60, then swap the Redback for two 90w Creambacks in a 2x12 I can wire in stereo. I won't get the full effect, but will get fatter chorus and some ping pong delay. I also think I'm robbing the power section by using it at low volumes in bridged mode. I'm definitely not driving that Redback whether I like the tone or not.

Next step is to put the EMGs back in and listen to what happens.

Hey John,

    Look at what you're saying here; that's a lot of gear changes all at once. Maybe start with the speaker change, since it seems very likely the redback isn't giving you the kind of sound you want. Who knows? The Carvin might work out well with the 90W Creambacks.
It's just a thought.

Harley 8)
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rnolan

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Re: I don't know where to begin
« Reply #29 on: Time Format »

Two cream backs wired stereo will work quite well IMHO.  I have one of my ADA split stacks wired stereo and while it's not as good as 2 separate cabs it's still quite good, and portable...
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