External Synths to Pulsar Analog Ins (RCA) - low levels

[Yogimeister]

Hi,

Probably a NewB question - but:

I have an old MicroQ and TX802 (Yay !) and when connected to my Pulsar inputs (directly via the RCAs) - I get a very low input level (Noise floor is around -75dB and signal is around -28dB (on the Scope mixer)

This is a problem because when bringing the volume up and compressing(rinse and repeat) - I can hear the background noise/hiss - as well and quantization noise sometimes ... (Especially with "quite" sounds/patches)



I asked about this at a local music/electronics shop and they said I needed a DI and a PreAmp ...
Im not "buying" the preamp theory yet - but never used a DI so I dont know what to think and if it should be necessary ...
(I thought the synth outputs were "line level" like the Pulsar inputs - but just "not Hot" ...
I also thought that this might be an issue with the "MicroQ" - but the TX802 behaves similarly ...)



What do you guys think/use.... ?

(P.S. I've already started saving up for a Ferrofish ...)

Thanks !

[Spielraum]

plan a:
check intern soundedit/extern output
1.) hardsynths set level out to max "high", "Pro" or "+4dB"
2.) set input level to -10dB "consumer" if A16 or other
3.) keep off hardware ground loops

plan b:
DI-box for line unsym > sym

plan c:
make music with noises
for more vitality between sounds
thats hot analog shit...
like BOYZ NOISE

[garyb]

some old boxes are pretty noisy, but if you go into the RCA inputs, the level should be good. are you sure the synth is turned up?

[Yogimeister]

Yeah - the synths are at max - and hard unison (with filters open on the MicroQ) ...

Are the Pulsar RCAs "pro" (+4dB) level ?
(I think the MicroQ is -12dB output level and sounds are usually lower to accomodate filter resonances without internal clipping ...)
I couldnt find any info on this in the Creamware/Waldorf resources ...


I am aware of the (-10?dB) switch on the A16 - which is why I think maybe I need another component between my external synth and RCAs (the manual talks about mic preamps, mixers and keyboard output - which I thought was equivalent to the TX802 for example ...)

Does anyone here connect ("old") external synths directly yo the RCAs ?
(Does anyone use a DI? The shop guy recommended a passive DI .. Not sure how much it costs ...)







Last but not least - while I like some BoyzNoise tracks - Im making percussive deep tech rather than pumping electro .... And the analog hiss is not like the crunchy noise they have ...
Its also not only background noise - the sounds kindof fade/bitcrush into it ... :/ Maybe nice for a few sounds - but not for several dozen tracks playing together ... (And Im not going to start making chiptunes

[garyb]

no, the RCA inputs are -20.

[Yogimeister]

-20dBFS ??

Im confused .... (Is the MicroQ supposed to be blasting hot on the RCAs if its output is ~-12dB ? (There is no mention of specs - let alone which dBs are mentioned in the various online posts I found ...)

The wikipedia entry for DI mentions that it converts unbalanced highZ signals to balanced lowZ
(Is this always the case where unbalanced is HighZ and vice versa - or are those independent?)


What is the impedance of the Pulsar RCAs? (I gathered they are unbalanced)
In this case - I understand that a passive DI wouldn't make a difference , right ?

[Yogimeister]

Is -20dB the "input level" / sensitivity - or does that mean that it attenuates a "full scale" line signal by 20dB ?

[garyb]

dude....
consumer(unbalanced) line level audio is referenced at -10 or -20db.
professional audio is referenced at +4db, and it is balanced.
the numbers only mean something compared to a reference level, a specific voltage. there is no standard, but everyone is in the same ballpark.

a synth of almost any kind is consumer line level, period. if it's pro line level, then the output will be balanced. your old synths are definitely consumer level, just like the RCA(unbalanced) inputs on the Scope card. after that, the level is what it is. it's always possible that one or the other synths outputs are bad, but it's not likely that both are bad, likewise with the cables. if both synths are using the same cable, then i'd try a different cable. it's very hard to say from your description if the audio level and noise level are normal or not. i would expect both synths to be on the noisy side.

some technical info:
https://en.wikipedia.org/wiki/Line_level

[Yogimeister]

Well - I apologize for not knowing this stuff by heart - but to be honest - it is a jumble of units that didnt really didnt add up to solve my problem.

Do -20 consumer level inputs "match" -20 cosumer outputs (line levels) ?
(I guess the MicroQ has low line level as it is said to be "not loud")

- and in this case - will a DI (passive - no amplification) help ?
(And what do you use with external synths (and will a A16/Ferrofish be any different ?))

Thanks

[garyb]

well, a DI takes line level unbalanced and then changes it to mic level, balanced.
this is pretty important because unbalanced lines suffer significant high and low frequency loss in distances much longer than 20'(18'6" to be more exact). converting the signal lets it go down a mic snake to a mixing board that's far away without significant signal loss. in this case, it probably won't help.

-10 or -20(both are considered consumer line level) input and outputs are about the same level, but from one device to another, there is a considerable variation in level. as i said, there isn't a standard, just a general consensus. these days, level are much more standardized, but...anyway, that's what the gain control is for. when you add gain, you raise noise as well as the signal you want. there's no way around this, even if you change the level to mic level and then add gain. in the end, line level is line level and the signal to noise ratio from the synth is the signal to noise ratio.

if the noise is actually from a ground issue, then using a DI to balance the signal might actually help. instead of a positive and then a negative that also carries ground, the positive negative and ground are separated in a balanced signal. then you can lift the ground and eliminate the noise. a transformer or IC keeps the two systems(Scope and the synth, for example) separated. the ground lift keeps the grounds of each unit from touching.

i usually use an A16, but going into the analog input isn't much different. many times, old gear is just noisy.

[Spielraum]

all perfect here
for short record-stem: pulsar/xite in;
for longer session: incl. A16 with di and other AD converter

- mks 70 (level: H)
- tx81z (little noisy charme, denoising sound = death )
- synthex
- sh101
- ms20
- prodigy
- sk20
- cs15
- prophecy
- 707
... rompler
.. etc
.

tip: test various cable