Noisy Amp?

[kr236rk]

HI,

Been using a Black Star amplifier into an analogue mixer for my MC7 DAW with no worries. The Blackstar HT 1R [1 watt] has 1/4" in and out sockets. The other day I experimented with a Vox AV15 [up to 15 watt] which has 1/4" in, but a mini jack socket out.

I cannot get a good sound from the Vox, there is a background whine. Is this something to do with the out socket or is the amp just too powerful to put through the mixer please?

Have tried both a mini-to-1/4" adaptor and then a straight mini jack cable to the mixer, I get whine whatever I do. Baffled.

Hate mini sockets

Thanks

[Rolling Estonian]

Is it a headphone out or a line out for a cab? If it's a line out it's designed to power a cab, not as a line out for a I/O. Could be bad.

M

[geobee]

Hi, the output socket you say you are using, is that the speaker output, because if it is, you will be in trouble for sure as the signal will be too much for the input to your mixer, and could well burn up the pre amp strip. Mixers and interfaces also for that matter, can only take a line level signal at best, not a speaker drive signal. You are talking volts from a speaker output, but you only want line level which is well under 1 volt, usually around 500 to 800 millivolts. No too many small amplifiers have a lin out fitted, but they often have a headphone output, this is where you could get lucky as the signal there could suit you better as it is taken from the pre amp usually, not from the speaker drive. You can have a sound tech fit a line out to the amps, it is just a couple of resistors off the speaker drive, and should not cost much to do. Did dozens of those mods in my working days before this great retirement. Best advice is to use the phones socket if fitted, and keep the volume control down. The noises you are hearing are probably from the fact that the signal is way too hot, and the mixer is going into
what we call oscillation from the over done signal. Hope this helps.Geoff

[geobee]

I would think those small amps would be combo, as in amp/speaker combined. They probably wouldn't have line outs on them, just a speaker drive socket. Line out is used to drive a power amp stage, not a speaker cab direct, wouldn't hear anything from the speaker.

[Mab098157]

Vox AV15 has aux in and phones out both in the mini jack. If your using the AUX, that is in in and will not work. Using phone...

Best advice is to use the phones socket if fitted, and keep the volume control down.

[kr236rk]

Thanks guys,

The Blackstar out socket is labelled 'Emulated output & headphone', the Vox is just labelled 'Phones', I can't see any socket for linking to a cab but that's not what I'm after. I guess there is too much sheer volume coming through the Vox phones socket, I need to experiment with very low levels.

It's funny there's no external cab sockets - perhaps they are hidden away inside?

Yes, these small amps must be combos, amp and speaker all in one.

Onward

[Ianpb]

A really stupid design oversight in these days of home recording. It's a lesson in being careful what you buy and making sure an amp does have a line-out, which the AV15 does not. I'd be inclined to install a line-out at the point where the preamp connects to the amplifier but, no doubt, it will all be mounted on a printed circuit board, which makes it more tricky if you don't know what you're doing. You also have to bear in mind that such a modification would invalidate the warranty, assuming it was bought new.

http://www.voxamps.com/AV15

[Acoustica Greg]

Hi,

You could always try miking the amp. Point a microphone like the Shure SM57 at the amp and record that way.

Greg

[geobee]

Very simple mod to do. From the speaker terminals, or internally at the output to the speaker, I think by memory, it is simply around a 22k 1 watt resistor to take a feed from the positive speaker line, and on the output end of that resistor, a 2.2k 1 watt resistor to ground, or the negative speaker connection will do. The Line out signal is then available at the junction of those two resistors, and the speaker negative. This will give a more true amp sound for electric guitar, than using the phone socket. Obviously I must add that if this simple mod is above ones understanding of electronics, best leave it to a tech savvy person. Should take less than 20 min to do. If it is done at the speaker connection terminals, even less.

[kr236rk]

Thanks,

The Blackstar 1watt doesn't have a dedicated line-out either, I go from the phones socket to the mixer - it works great - best sound I have got into a DAW recording software. I can use a full set of pedals with the Blackstar as well, wah, delay, noise gate, the lot.

Was amazed to find the Vox only had one 1/4" socket, I associate quality amps with pig plug sockets. I guess it's because it's a modern tube amp that they start sticking these pesky mini jack sockets all over the place? Have an excellent music shop locally, I wonder if they'd customise this amp for the mixer, and add a 1/4" socket while doing so? Any more detailed specs for this modification appreciated

If I were going to mic the Vox I'd need a soundproof recording studio, I am only DAW 'sound dampened' and have zero ventilation so that's sadly not an option. Maybe one day but not any time soon.

[kr236rk]

Found a workaround

Ran the phones out to a headphones pre-amp, then ran the out from the pre-amp to the mixer. No more whine and I get the full spectrum of channels / effects from the AV15.

Now I just have to wait for my pinky to recover from getting snagged in a window latch two nights ago then I can add the AV15 to a DAW project

Thanks to all!

[WhiRz]

Nice tips I didn't thinked of that one ^^.

I always use loadbox as DI and IR cab simulator pluging in my DAW (for tube amp only).

Nice one ^^.

[kr236rk]

Thanks,

I went back to the Black Star tube amp in the end - phones out straight into mixer, straight into interface, that's my set up now. The AV15 I hope to use live at some stage, I still think it's too powerful for a DAW hookup unless you mic it of course.