"Pre Out" controlled by Volume?

[DeepEnd]

Does anyone know if the "Pre Out" on my Fender FM65R is affected by the Volume control? The signal seems very weak but because of the way the amp is designed I need to keep the volume on both the amp and guitar turned down or it's deafening. (I play in worship in a smallish church so I don't need excessive volume but the sound guy wants to be able to control the volume from the mixing console, thus the use of the "Pre Out".) Here's what the manual has to say:

PRE OUT/PWR IN - (1) Effects Loop - Connect PRE OUT to an effects device input, then connect the effects device output to PWR IN. (2) Multiple Amps - Connect the primary unit’s PRE OUT to the auxiliary unit’s PWR IN. The primary unit is used to control all auxiliary amps. (3) Recording or Reinforcement - Connect PRE OUT to sound equipment’s input. Both jacks use a TS (Tip-Sleeve) standard type plug for connections. PRE OUT includes onboard tone shaping.

I get "tone shaping"--it means the EQ controls affect the signal. But what about Volume?

[1001gear]

The vol should be preout voltage. How most instrument amps work. The amp side just amplifies whatever it gets. Depending on the board you may not need full volume. The engineer can determine the optimum signal level.

[WRGKMC]

Does anyone know if the "Pre Out" on my Fender FM65R is affected by the Volume control? The signal seems very weak but because of the way the amp is designed I need to keep the volume on both the amp and guitar turned down or it's deafening. (I play in worship in a smallish church so I don't need excessive volume but the sound guy wants to be able to control the volume from the mixing console, thus the use of the "Pre Out".) Here's what the manual has to say:

 

I get "tone shaping"--it means the EQ controls affect the signal. But what about Volume?

 

Pre amp outputs are nearly always affected by the channel volume. Channel volume is part of the preamp circuit and comes before the amps EQ.

 

If the amp has a main volume it adjusts the power amp gain and is usually after the preamp output. This only makes sense because you want to have your effects loop between the preamp and power amp. The preamp out takes the signal from the preamp only. The return goes to the power amp. With nothing plugged into those jacks, you have a straight connection from the preamp to power amp. When you plug into the effects loop you break the connection between the preamp and power amp and insert some other piece of gear in series.

 

Some amps break that connection when you plug into one jack or the other. This may not work out so well if you want to use this as a "Tap" for the PA because it cuts the signal to the power amp so all you do get is the signal to the PA and no sound from the amp.

 

If you have this problem there's a pretty simple fix. You can use a Y jack to connect the pre out to the power amp in and use the Y of the jack to send to the PA, I have a couple of amps that cut the signal to the power amp and its the only way to use them as a line out send. (besides using an effects in that loop that has an extra output.

 

Other amps may have an effects loop and a line out. Whenever you have that, you always want to use the line out so you don't have to deal with the effects loop cutting the signal to the power amp.

 

In all cases your input channel volume will affect the amps output. You don't want to be messing with the amps volume once the amp is set because you'll be affecting the volume in the PA which is the sound mans job to take care off.

 

If you want to have your own independent control over your amps volume and not have it affect the PA, then you have to take the signal tap before the amp. You can do this with a DI box straight from the guitar or after any effects pedals. Straight from the guitar means you have to keep your instrument volumes up and its going to be 100% clean tones. lf you take it after the effects pedals where it plugs into the amp, you will get those effects through the PA.

 

Personally I'd tell the sound gut to mic the amp. Direct sends to a PA sound better for bass. Unless the amp has a speaker emulated line out a direct send usually sounds sterile and the tone can be way off because there's no speaker there to color the sound. A mic will capture the speaker coloration and you aren't having to worry about your tones sounding different.

[DeepEnd]

. . . If the amp has a main volume it adjusts the power amp gain and is usually after the preamp output. . . .

 

. . . Some amps break that connection when you plug into one jack or the other. . . .

 

. . . Personally I'd tell the sound gut to mic the amp. . . .

As it happens, the "Drive" channel does have dual volume controls labelled "Drive" (Duh!) and "Volume." I'll have to check and see if the "Drive" affects the output volume. If it doesn't, I can probably tweak my settings by turning down the "Drive" and turning up the "Volume." Plugging into the "Pre Out" doesn't break the connection, thank goodness, but thanks for your concern. As for miking the amp, I don't think there's a spare mike available but honestly I'm not particularly worried. I play electric maybe 40% of the time and I can live with not having my electric go through the PA. Our other guitarist plays his Ibanez electric exclusively these days so his amp needs to be miked.

[WRGKMC]

As it happens, the "Drive" channel does have dual volume controls labelled "Drive" (Duh!) and "Volume." I'll have to check and see if the "Drive" affects the output volume. If it doesn't, I can probably tweak my settings by turning down the "Drive" and turning up the "Volume." Plugging into the "Pre Out" doesn't break the connection, thank goodness, but thanks for your concern. As for miking the amp, I don't think there's a spare mike available but honestly I'm not particularly worried. I play electric maybe 40% of the time and I can live with not having my electric go through the PA. Our other guitarist plays his Ibanez electric exclusively these days so his amp needs to be miked.

 

I have a mini Marshall with the same thing. It uses two volumes in the preamp to adjust two stages of preamp gain. Both come before the preamp out. Not completely sure f yours is the same. If you have some other amp, even a Hi Fi with an auxiliary input, headphone amp, Tape recorders, anything that has a line level input (even a computer sound card has a line level input) you can plug the amps preamp output into it to hear what the preamp send captures.

[DeepEnd]

I can run a cable from my amp to a bass amp. Our other guitarist was playing sound man temporarily and told me there was no signal from my amp through the "Pre Out." I suspected BS and checked it later by connecting my amp to the bass amp, which is how I know there's a signal, just a low level one. I can fiddle with the "Drive" and "Volume" controls and see if both affect the output level. The main problem is that those FM65Rs have a ton of gain and I need to keep everything turned down or I'll deafen everyone. I have the "Drive" set at 3, the "Volume" set at 2 1/2 and the volume on my guitar barely turned up and it's adequately loud for my needs.

[WRGKMC]

Sounds like a signal level issue then. Pre outs can be line level or instrument level. Instrument level suits effects boxes better while line level is better for rack units and mixers.

 

It does sound like you have two issues though. One seems to be an issue with the mixer gain. It may not have sufficient gain to amplify the pre signal, (or it may be the guy thought you were loud enough with your stage volume already and wanted to deflect the situation and tell you not to bother with it)

 

If it truly was low you could use an inexpensive DI box. The DI would convert the preamp signal to an XLR mic signal that you could run into a normal mic connection. The DI box should have a DB switch that can drop the signal input from Zero, to -10db to -20 db so you'd have some control of the gain on your end. This way you can get the guitar levels on the mixer in the same ball park as the vocal mics and not have it over or under boosted.

 

If you want to use a high impedance send from the amp and its too weak for the PA input, put a booster after the pre out. It can be a clean gain booster or maybe you want a compressor or drive box to add a little boost plus some of those effects. Compression can even up what's hitting the PA and give the signal even dynamics instead of jumping out. A gain box can be dialed up to remove some edge and get some additional drive. An EQ pedal can boost the signal and dial out some of the lows and highs and leave the mids so it doesn't interfere with the main vocals.

 

The other issue still remains where your amps stage volume is too loud though. There are a number of ways to combat that. Build yourself a cab with smaller speakers, Buy some lower SPL speakers. Add a switch to the cab to reduce the number of speakers you're running or using a hot plate dummy load to reduce the heads output are options. You can even make a cover that fits the front of the cab to act as a shutter and block some of the speakers output.

 

You can also put an attenuator in the effects loop. Pre out goes through some pedal like a compressor then back in to the power amp. You can then dial back the amount of signal getting to the power amp and dial up the preamp gain where it feels comfortable. It can be any number of pedals so long as it can attenuate. A comp can be set so it doesn't compress and just dial back the volume or maybe you want some sag to emulate the touch you get playing through a tube amp.

 

It could be an EQ pedal and dial back all the frequencies, it could be a gain box dialed up dry and dial the output or input down.

 

You'd still need to tap the preamp signal to send to the PA with a Y jack but that's about all you'd need. You can experiment trying any or all of these till you find what suits the situation best. This is what a good sound man will do to meet the situation as needed as well.

 

 

[Phil O'Keefe]

I can run a cable from my amp to a bass amp. Our other guitarist was playing sound man temporarily and told me there was no signal from my amp through the "Pre Out." I suspected BS and checked it later by connecting my amp to the bass amp' date=' which is how I know there's a signal, just a low level one. I can fiddle with the "Drive" and "Volume" controls and see if both affect the output level.[/quote']

 

That would tell you definitively whether or not those controls affect the line level output's overall signal level - I suspect they will, but doing that test yourself is a very good idea.

 

The main problem is that those FM65Rs have a ton of gain and I need to keep everything turned down or I'll deafen everyone. I have the "Drive" set at 3, the "Volume" set at 2 1/2 and the volume on my guitar barely turned up and it's adequately loud for my needs.

 

Unless I miss my guess, the volume control in the drive channel acts like a master volume for that channel. You can adjust the amount of dirt in the signal by turning up the drive, and the overall output level of that channel is controlled by the volume knob. You'd probably be better off in terms of overall gain staging by turning up your guitar and turning down the volume from 2 1/2 to whatever level you find comfortable.

 

You may just have too much amp for the gig and the room... have you considered using something with a bit less wattage? It sounds like a 15-20W amp might be better suited to your needs.

[DeepEnd]

Sounds like a signal level issue then. . . .

 

. . . If it truly was low you could use an inexpensive DI box. . . .

 

. . . The other issue still remains where your amps stage volume is too loud though. There are a number of ways to combat that. Build yourself a cab with smaller speakers, Buy some lower SPL speakers. Add a switch to the cab to reduce the number of speakers you're running or using a hot plate dummy load to reduce the heads output are options. You can even make a cover that fits the front of the cab to act as a shutter and block some of the speakers output.

 

You can also put an attenuator in the effects loop. . . .

 

. . . You'd still need to tap the preamp signal to send to the PA with a Y jack but that's about all you'd need. You can experiment trying any or all of these till you find what suits the situation best. This is what a good sound man will do to meet the situation as needed as well.

First, I'm already using a DI box between the amp's "Pre Out" and the mixer but thanks for the suggestion. Second, this is an integrated amp with a single 12" but again thanks for the suggestion. Our sound guy is good with electronics and I might have him build me a hot plate. But the simplest solution seems to be using a pedal with its own gain control and a "Y" adapter. There are a few on the local CraigsList for $15 and up. Looks like one of these would work too: http://www.ebay.com/itm/Volume-Box-effect-loop-volume-attenuator-for-Fender-Hot-Rod-Blues-Deluxe-Deville-/151618161023?pt=LH_DefaultDomain_0&hash=item234d25897f.

 

That would tell you definitively whether or not those controls affect the line level output's overall signal level - I suspect they will' date=' but doing that test yourself is a very good idea.[/quote']

Unfortunately, I suspect the same. I'll have a chance to test it later tonight.

 

 

Unless I miss my guess' date=' the volume control in the drive channel acts like a master volume for that channel. You can adjust the amount of dirt in the signal by turning up the drive, and the overall output level of that channel is controlled by the volume knob.[/quote']

That's exactly what it's for.

 

You'd probably be better off in terms of overall gain staging by turning up your guitar and turning down the volume from 2 1/2 to whatever level you find comfortable.

 

You may just have too much amp for the gig and the room... have you considered using something with a bit less wattage? It sounds like a 15-20W amp might be better suited to your needs.

I started out with a 25 Watt Roland 1X10. It would make my ears ring at home but it wasn't loud enough for worship. I figured going to a 65 Watt 1X12 would be a good upgrade. It was cheap and reasonably light and I know Fender makes a good amp so I bought it. I've read a number of reviews of the FM65R and they all said pretty much the same thing: It gets really loud above 3. Since 1 is Off on this amp, turning the Volume below about 2 isn't really an option. I could plug my guitar into the jack intended for active pickups, which has a bit less gain, but that wouldn't solve the problem with the "Pre Out" level.

[WRGKMC]

There's a number of Fenders that will ramp up in volume quickly like that. My buddy has a 100w solid state Princeton where the volume goes from zero to maybe 20w between zero and one just cracking the volume knob. What I'd do is use a volume pedal and drive pedal before the volume pedal. I'd adjust the amp so it would sound decent, attenuate the volume a bit with the volume pedal then get my gain from the pedal.

 

Trying to get drive from the amp was too loud at rehearsal so I did it with pedals instead. It wasn't a tube amp so it wasn't like I was giving up any tube drive tones. I haven't found a SS amp yet where I couldn't get as good or better tones from drive pedals.

 

I have several SS amps including my Marshall which has dual channel switching for crunch and lead. The drive channels are pretty much a one trick pony and I got tired of the same old drive tones. When I run my pedal board I set the amp for a good clean tone playing chords with no pedals running. From there I do everything from the pedals.

 

I adjust the volume with a volume pedal, I use compression to add some sustain, I have maybe 3 or 4 different drive boxes that give me popular drive tones, I use a slow mild chorus to give the sound depth and movement and light echo to add note trails. I usually use the amps Reverb and when the amp is set for clean that reverb sounds pristine.

 

The only time I touch the amps settings is when I initially power up and set its volume and tone for the room. If the band starts getting too loud I may need to give it a small tweak here or there for overall blending purposes but that's about it.

 

Now if it was a nice tube amp with juicy tube saturation and speaker drive, then I'd work things allot different.

I'd set the amp where its on the edge of driving and has punchy but not overly driven tones. I'd use a Tube screamer pedal to drive the amp up to get nice leads. I use a compressor in front of the TS to get sustaining leads when using the TS and a nice clean jangle with a little sage when the TS is off. I may put a chorus and or echo in the effects loop, but if the amps doesn't have a loop I go without those. I learned long ago you don't want drive after time based effects because you get gritty modulated tones. The tube amp and speaker does most of the driving so I'll add any chorus or echo at the PA which captures all the drive before hand. I'd mic it too because I want to capture the speaker drive.

 

Having the right wattage amp for the gig is important using a tube amp because you dial the amp for the best tone and whatever the loudness winds up being is immaterial. Hopefully the amp is low enough for good stage volume and the sound man can do whatever he wants for room volume. This is why 30W tube amps are so popular. They produce the right amount of stage volume so the band can hear you without melting peoples faces off. You can gig without micing the amp or you can mic it for larger venues.

 

SS amps are tough to get right. Allot of it depends on the speaker and how you dial up the sound. I have a small 65W Peavey Studio combo I bought awhile back. Its supposed to drive a 12" speaker but when I bought it, the head was mounted in a Marshall 30 cab which took a 10" speaker. I bought a 65W 10" Jensen for it and the amp is plenty loud but it lacks bottom end. I may eventually make a 2X10" or 1X12" cab for it to get the tone right. 65W is actually too loud for my needs. I have a 15W Marshall and a 10W Ampeg which are pretty much ideal when used together. I may eventually dump all three and get a good 20/25W tube combo which is the ideal rehearsal amp. Anything louder and the singer cant get up above the amp volume without feeding back. I have the big stuff for gigs but the ideal combo is a tricky item to get right.

 

[Phil O'Keefe]

I started out with a 25 Watt Roland 1X10. It would make my ears ring at home but it wasn't loud enough for worship. I figured going to a 65 Watt 1X12 would be a good upgrade. It was cheap and reasonably light and I know Fender makes a good amp so I bought it. I've read a number of reviews of the FM65R and they all said pretty much the same thing: It gets really loud above 3. Since 1 is Off on this amp, turning the Volume below about 2 isn't really an option. I could plug my guitar into the jack intended for active pickups, which has a bit less gain, but that wouldn't solve the problem with the "Pre Out" level.

 

You could try a power attenuator / power soak / hot plate to knock the volume down a bit. Another possibility would be to use baffles to keep the sound hitting the audience down a bit - I've seen guys using those plexiglass panels in front of amps in church services, or even mini DIY goboes. A similar, but even more effective approach would be to build some sort of an iso box you can put the amp in. With a mic inside, or something like a Hughes & Kettner Red Box, you can send the signal to FOH (the sound board) and let the FOH engineer handle your levels for the house. Have them also send you some to your monitors so you can hear yourself, and bob's your uncle.

 

One other thing you might consider is installing a less efficient speaker. I have no idea what the efficiency of the stock speaker in that amp is, but let's take a guess and say it's 96 dB @ 1w / 1m. If you put in a speaker that only put out 88dB or 90dB @1 w / 1m, you'd be knocking off six or eight decibels, which would definitely be noticeably quieter.

[DeepEnd]

Update: I checked last night and, alas, the "Drive" control does in fact affect the "Pre Out" volume as I suspected it would. Looks like I'll have to either add a pedal or live with it as is.

[WRGKMC]

Putting an attenuator in your effects loop is still a good alternative. It's inexpensive and it will cut down the power amp/speaker volume.

 

Something like this could be made for a few bucks.

 

https://www.gearslutz.com/board/attachments/newbie-audio-engineering-production-question-zone/400359d1401116406-newbie-important-questions-about-yamaha-spx90-connectivity-levels-line-attenuator.jpg

 

With this in your effects loop acting as a master volume You'll be able to crank your preamp volume and gain up to suitable levels then turn down how much is getting to your power amp to actually drive the speaker. If you also want to use the DI box there should be no issue. Just put the DI before this attenuator.

 

You can also search around and buy one fairly cheap. This ones stereo, but you can just use one side. http://www.electronicplus.com/images/products/10-105.jpg Its 10-105 on this page http://www.electronicplus.com/content/ProductPage.asp?maincat=as&subcat=am3 You can find others or have your buddy make one up for you.

 

Soldering a 5K pot and a couple of jacks together is a very easy way to go. By a short guitar cable, Metal box and a 5K pot. Cut the cable in half, drill three holes in the box, mount the pot, run the two cables in through the other two holes, solder them to the pot, bam you're done.

 

You can now adjust your power amp down as needed so you can run your preamp volume and gain as high as you want and not blow people away. The effect of this on a SS amp is similar to what a hot plate does to attenuate a speaker except its a whole lot cheaper. You're talking a few dollars vs a couple of hundred dollars. It will work OK as long as you're only having to crank the power amp down a little. If you go too far it may make the sound a little claustrophobic.

 

You could also easily mount this arrangement inside the amp if you like the way it works. There isn't much involved drilling a hole in the back, mounting an extra pot and wiring it in series with the effect loop, and you can do it so the effects loop still works.

[DeepEnd]

Putting an attenuator in your effects loop is still a good alternative. It's inexpensive and it will cut down the power amp/speaker volume.

 

Something like this could be made for a few bucks.

 

https://www.gearslutz.com/board/attachments/newbie-audio-engineering-production-question-zone/400359d1401116406-newbie-important-questions-about-yamaha-spx90-connectivity-levels-line-attenuator.jpg . . .

Nice idea. I could add a "Y" before the pot for a bypass output (for the DI) and an output controlled by the pot (for the power amp). One question: I note the pot is designated as "5K". Does that mean I can't use a regular guitar pot (i.e., 250K, 500K, 1M)?

[WRGKMC]

Nice idea. I could add a "Y" before the pot for a bypass output (for the DI) and an output controlled by the pot (for the power amp). One question: I note the pot is designated as "5K". Does that mean I can't use a regular guitar pot (i.e., 250K, 500K, 1M)?

 

Maybe, Maybe not. Its depends on whether or not the signal is line level or instrument level.

Line level can be a 600 ohm impedance line so a 5~10K ohm pot is plenty enough to not load the signal when connected yet be enough resistance to have a good linear sweep.

 

That's one of the issues besides loading the signal down. If the resistance is too high, you may go from full off to full on within 1/10th of a turn on the pot. From then on, the pot has no effect. That makes it very difficult and dodgy to adjust at best. You want the pot to match the signals impedance range so when you turn down, going from say 10 to 5 on the knob cuts the signal in half. Each number cutting the signal down by 1/10th.

 

Anyway, its a real simple thing to try if you have some pots lying around. Unscrew one end of a guitar cord so the contacts are exposed and plug it into the send and return. Take the center and outside leads of a pot and jumper it to the contacts of the cord and see what kind of range you got on the pot.

 

By the way, the pot has to be wired like that diagram and have the in and out marked. If you swap the input and outputs around the pot will attenuate the preamp send signal and also your Y jack to your PA.

[DeepEnd]

Thanks, I did my reading when I replaced the pots in my bass. I asked about the impedance of the pot because I have a new 500K pot lying around and I thought it might be one less part to buy. BTW, as you probably suspected, I'll be using 1/4" jacks vs. plugs and plugging cables into the resulting box. There's a local shop, Gateway Electronics, that should have everything I need. If there's anything they don't have (their web site doesn't show pots, which seems odd), there's always Radio Shack. It'll be a couple of weeks before I have time to buy everything but it shouldn't take long to build. I'm guessstimating maybe $15 in parts (project box, 3 jacks, pot, wire, knob) and whatever time it takes to assemble. I should probably get hold of a label maker and make it pretty with the jacks identified. Maybe I can even snap a few pics for the DIY Forum.

[WRGKMC]

Very cool indeed. It should do the trick. You have the pot so try it. You can build the box with pigtails (leads and plugs on the ends) or you can build it with jacks you plug cords into. You'll need two cords if you install jacks. The third jack parallels the input connection and goes to the PA when needed.

 

You can even install an XLR jack for a mic cord instead of a guitar cord so long as you wire it high impedance. If the signals too hot for a mic input on the PA, wire the jack to the attenuated output instead of the input. (or put a switch to swap between the input and output for the PA feed)

[DeepEnd]

Very cool indeed. It should do the trick. You have the pot so try it. . . .

 

. . . You can even install an XLR jack for a mic cord instead of a guitar cord so long as you wire it high impedance. . . .

A 5K audio taper pot is $3.49 at Radio Shack so I'm not worried. I'll go ahead and buy a proper pot. Thanks for the suggestion of an XLR jack. I hadn't thought of doing that but it would eliminate the need for a DI box. I assume I'd just short the ground pin to the negative one? The diagrams I've seen have a ground wire. Also, we're talking about a fairly long cable run, say 50+ feet, so I'm not sure an unbalanced line would work well. Thanks.