Hi everyone,
Firstly, sorry if this is the incorrect forum to post this. I'm relatively new to the audio world so I still get my terms mixed up.
I currently have 3 sources, all going into a Bottlehead S.E.X. 2.1 Amp:
Mega RP1 Turntable -> Rega Fono Mini Preamp (hoping to change)
Xonar Essence STX Sound Card (PC w/ FLAC audio/movies etc.)
Generic 3.5mm, used for taking in Xbox, Laptop, Phone, etc.
I'm hoping to combine 2 more of these (ideally I'd have 4 inputs) combined in to a single RCA source to be fed in to my amp.
The main option I've found is the Rolls MX42, but reviews are saying that it attenuates the signal, which I'd like to avoid. I understand that using a non-powered mixer (which I'd prefer) will attenuates the signal to some description, but I'm hoping to avoid this or go with a well recommended powered one (should that be the case).
I've thought about making my own, but will all my Google-foo, I've not managed to find any tutorial or schematics (which I probably couldn't interpret anyway) to build one myself.
Hopefully someone here will have an idea or be able to point me in the right direction? If there's a specific item I'd prefer it to be available in the UK in case I decide to return it, but I understand that this may be asking a lot.
Thanks,
Joseph Duffy
Firstly, sorry if this is the incorrect forum to post this. I'm relatively new to the audio world so I still get my terms mixed up.
I currently have 3 sources, all going into a Bottlehead S.E.X. 2.1 Amp:
Mega RP1 Turntable -> Rega Fono Mini Preamp (hoping to change)
Xonar Essence STX Sound Card (PC w/ FLAC audio/movies etc.)
Generic 3.5mm, used for taking in Xbox, Laptop, Phone, etc.
I'm hoping to combine 2 more of these (ideally I'd have 4 inputs) combined in to a single RCA source to be fed in to my amp.
The main option I've found is the Rolls MX42, but reviews are saying that it attenuates the signal, which I'd like to avoid. I understand that using a non-powered mixer (which I'd prefer) will attenuates the signal to some description, but I'm hoping to avoid this or go with a well recommended powered one (should that be the case).
I've thought about making my own, but will all my Google-foo, I've not managed to find any tutorial or schematics (which I probably couldn't interpret anyway) to build one myself.
Hopefully someone here will have an idea or be able to point me in the right direction? If there's a specific item I'd prefer it to be available in the UK in case I decide to return it, but I understand that this may be asking a lot.
Thanks,
Joseph Duffy
Do you want to play more than one at a time?
Or do you want to switch between them and control the volume?
When you said "RCA" I thought you might have a vintage bit of gear made by RCA for the studio!
In reality you want to attenuate the signal for most playback. An unattenuated signal that has peaks near maximum or "0" (from a digital standpoint) will be extremely loud. However there are some cases where additional gain is required, that's for low average level recordings.
That little Bottlehead has precious little headroom since it is a low power amp, so one would want to not overdrive the input.
What you want is generally called a "pre-amp" which has switching, gain and a volume control. Some have tone controls. Alternately there are units that are either "buffered" (unity gain amplification) or "passive" which has only attenuation and usually switching between sources.
I happen to use the latter - but I have ample gain available from my sources.
Or do you want to switch between them and control the volume?
When you said "RCA" I thought you might have a vintage bit of gear made by RCA for the studio!
In reality you want to attenuate the signal for most playback. An unattenuated signal that has peaks near maximum or "0" (from a digital standpoint) will be extremely loud. However there are some cases where additional gain is required, that's for low average level recordings.
That little Bottlehead has precious little headroom since it is a low power amp, so one would want to not overdrive the input.
What you want is generally called a "pre-amp" which has switching, gain and a volume control. Some have tone controls. Alternately there are units that are either "buffered" (unity gain amplification) or "passive" which has only attenuation and usually switching between sources.
I happen to use the latter - but I have ample gain available from my sources.
Do you want to play more than one at a time?
Or do you want to switch between them and control the volume?
When you said "RCA" I thought you might have a vintage bit of gear made by RCA for the studio!
In reality you want to attenuate the signal for most playback. An unattenuated signal that has peaks near maximum or "0" (from a digital standpoint) will be extremely loud. However there are some cases where additional gain is required, that's for low average level recordings.
That little Bottlehead has precious little headroom since it is a low power amp, so one would want to not overdrive the input.
What you want is generally called a "pre-amp" which has switching, gain and a volume control. Some have tone controls. Alternately there are units that are either "buffered" (unity gain amplification) or "passive" which has only attenuation and usually switching between sources.
I happen to use the latter - but I have ample gain available from my sources.
Yes, I'm wanting to play multiple sources at once. A "switch" is an acceptable fallback plan, but I'd really like to be able to play multiple sources at once.
The only reason I was discussing the mixer not attenuating the signal is that the signal is at a good level as it is now; I don't need too much amplification at the amp level and my pre-amp happily amplifies the audio from my turntable.
Since I already have a pre-amp and none of my sources are particularly in need of further amplification, I was hoping that I would just be able to get an RCA "mixer"?
I've got one, a Herald Electronics RA88a. It was very hissy when I got it, so I modified it to hiss less and have less hum. It has two RIAA inputs, a CD input, and a DJ microphone input which I changed the amplification factor on to take the earphone source of a (mono) FM radio. If all inputs are on all the time, then you don't have to walk around the piano (table) to change the input "switch" every time you change sources. It has RCA jacks in and out. This is an active circuit, originally having 4558 op amps which I upgraded to lower hiss ST33078. Some power supply redesign was necessary to eliminate the resulting oscillation. I also pulled the power transformer and switch out of the enclosure to reduce the hum, converting it to a wall transformer.
If you want something more competent out of the box, look for a Peavey DJ mixer. They were in the catalog but I've never seen a used one on craigslist.
Regular PA mixers do not have the RIAA input curve, much less two of them. They are also usually 1/4 phone jack input.
I'd stay away from numark or behringer, the photos I've seen contain surface mount components, push in ribbon connectors, and as such are probably not modifiable to improve to high fidelity. Push in connections are **** anyway, after a 30 year battle with the phone company I finally got rid of the connector the box outside that needed re-seating daily to keep the DSL speed up. Reliable oxygen resistant connections are mash together crimp (AMP), or solid state solder.
If you want something more competent out of the box, look for a Peavey DJ mixer. They were in the catalog but I've never seen a used one on craigslist.
Regular PA mixers do not have the RIAA input curve, much less two of them. They are also usually 1/4 phone jack input.
I'd stay away from numark or behringer, the photos I've seen contain surface mount components, push in ribbon connectors, and as such are probably not modifiable to improve to high fidelity. Push in connections are **** anyway, after a 30 year battle with the phone company I finally got rid of the connector the box outside that needed re-seating daily to keep the DSL speed up. Reliable oxygen resistant connections are mash together crimp (AMP), or solid state solder.
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