Hello guys. Bouth these modules and assembled in a case from audiophonics. I will redo the internal wiring, I dont like it.
I hooked it up to a source playing sin wave signal at 1kHy. I get 1.12V out of the source (SFF pc, Im in a hotel on a business trip). The preamp has 5 gain stages.
The toroids are 15-0-15 each. Opamp in preamp is NE5532P and in converter JRC4580DD.
When I set the gain to LvL0, I measure 2.54V on the preamp out, and about 3.8V from the converter when volume set to 0dB.
At gain LvL1 its 4V and 5.6V when set to 0dB
At gain Lvl 2 higher and then at LvL3 even more.
At Lvl5 I have almost 8,7V on the converter out to XLR. However, at LvL4 its 9.56V
Is the Muses module broken? Why such high voltage? I want to use it with a Hypex UcD180 power amp that will be build once I get home.
I have no experience or knowledge building preamps :d thats why I chose the modules. I thought just put it together and all will be fine.
Danny
I hooked it up to a source playing sin wave signal at 1kHy. I get 1.12V out of the source (SFF pc, Im in a hotel on a business trip). The preamp has 5 gain stages.
The toroids are 15-0-15 each. Opamp in preamp is NE5532P and in converter JRC4580DD.
When I set the gain to LvL0, I measure 2.54V on the preamp out, and about 3.8V from the converter when volume set to 0dB.
At gain LvL1 its 4V and 5.6V when set to 0dB
At gain Lvl 2 higher and then at LvL3 even more.
At Lvl5 I have almost 8,7V on the converter out to XLR. However, at LvL4 its 9.56V
Is the Muses module broken? Why such high voltage? I want to use it with a Hypex UcD180 power amp that will be build once I get home.
I have no experience or knowledge building preamps :d thats why I chose the modules. I thought just put it together and all will be fine.
Danny
Attachments
Some considerations:
On level 0:
Vin = 1.12V -> Vout = 2.54V (A = 1.5x) ; ConvOut = 3.8V (@ 0dB)
On level 1:
Vin = 1.12V -> Vout = 4.00V (A = 1.4x) ; ConvOut = 5.6V (@ 0dB)
On level 2:
Vin = 1.12V -> Vout = --- V (A = ---) ; ConvOut = --- (@ ---dB)
On level 3:
Vin = 1.12V -> Vout = --- V (A = ---) ; ConvOut = --- (@ ---dB)
On level 4:
Vin = 1.12V -> Vout = --- (A = ---) ; ConvOut = 9.56V (@ ---dB)
On level 5:
Vin = 1.12V -> Vout = --- (A = ---) ; ConvOut = 8.7V (@ ---dB)
Some data is missing here.
Are the measured values Vrms, Vpeak or Vpeak-peak?
Counting from level 0 to level 5, these are six levels in total.
-> Are the outputs of level 4 and 5 exchanged?
The converter pcb has five Hongfa relays, switching between various levels (assumption).
There are three stereo Cinch connectors.
There are two XLR connectors wired to the preamp board.
Following the cables, one cable from the converter goes astray.
On level 0:
Vin = 1.12V -> Vout = 2.54V (A = 1.5x) ; ConvOut = 3.8V (@ 0dB)
On level 1:
Vin = 1.12V -> Vout = 4.00V (A = 1.4x) ; ConvOut = 5.6V (@ 0dB)
On level 2:
Vin = 1.12V -> Vout = --- V (A = ---) ; ConvOut = --- (@ ---dB)
On level 3:
Vin = 1.12V -> Vout = --- V (A = ---) ; ConvOut = --- (@ ---dB)
On level 4:
Vin = 1.12V -> Vout = --- (A = ---) ; ConvOut = 9.56V (@ ---dB)
On level 5:
Vin = 1.12V -> Vout = --- (A = ---) ; ConvOut = 8.7V (@ ---dB)
Some data is missing here.
Are the measured values Vrms, Vpeak or Vpeak-peak?
Counting from level 0 to level 5, these are six levels in total.
-> Are the outputs of level 4 and 5 exchanged?
The converter pcb has five Hongfa relays, switching between various levels (assumption).
There are three stereo Cinch connectors.
There are two XLR connectors wired to the preamp board.
Following the cables, one cable from the converter goes astray.
Hello Citizen
Some more information:
- on the preamp PCB, far left is OUTPUT, that is hooked up to converter INPUT on the green PCB far right. Green PCB upper and lower solder points are OUTPUTS, those go to XLR sockets.
The 3.5mm Jack is on INPUT 1 on preamp, second from left. Then the 3 RCA INPUTS.
What is puzzling is, that at Gain 0 there is no change in Voltage on XLR outputs for about 24dB range on the preamp (from -65dB to -40dB). Then it starts to climb all the way to 3,8V at 0dB.
My concer is that when i hook up the power amp, I dont want to fry it with too high voltage on the input. In the datasheet it say +/-12V Input....
When I redo the wiring (waiting on hook-up wire from ebay) I will do the measurements again at each Gain setting.
Should I use different frequency or wave type? As I said, I am very new to this.
Danny
Some more information:
- The preamp is the black PCB, converter is the green PCB.
- 3x RCA input
- 1x 3.5mm Jack input at front (not visible, cable goes underneath the preamp PCB)
- Gain 4 and 5 are not swapped, that is what I get on the xlr output
- I measure with multimeter in V-AC with sinewave signal at 1kHz from PC (hence 1,12V) with negative on chassis and positive on signals
- on the preamp PCB, far left is OUTPUT, that is hooked up to converter INPUT on the green PCB far right. Green PCB upper and lower solder points are OUTPUTS, those go to XLR sockets.
The 3.5mm Jack is on INPUT 1 on preamp, second from left. Then the 3 RCA INPUTS.
What is puzzling is, that at Gain 0 there is no change in Voltage on XLR outputs for about 24dB range on the preamp (from -65dB to -40dB). Then it starts to climb all the way to 3,8V at 0dB.
My concer is that when i hook up the power amp, I dont want to fry it with too high voltage on the input. In the datasheet it say +/-12V Input....
When I redo the wiring (waiting on hook-up wire from ebay) I will do the measurements again at each Gain setting.
Should I use different frequency or wave type? As I said, I am very new to this.
Danny
Much more clear now.
1Vac (rms) on an input (miniJack or RCA's), measured 1.12Vac with a multimeter (make a attenuater with a 12 ohm and a 100 ohm resistor for 1.00Vac).
This is applied to the volume board (Muses), but no regulation from -65 to -40 dB. At 0dB is the converter output (level 0) already 3.8Vac. Roughly times three is peak-peak: 14.5Vpp. The amp can handle +/-12Vpp, so that's still save.
What is the output level of the Muses?
The converter is an unbalance-balanced converter. I see 10k and 2k2 resistors alongside the dual opamps. The amplification can be set at 10k/2k2= 4.5x.
3.8Vac / 4.5x = 840mVac, which is acceptable. The amplification is a bit high. I think the converter is to be used for line level to pro level conversion, that's ~150mV to ~775mV (5.2x).
If the output from the Muses is high, the output from the converter is high. But this can be modified... if a circuit drawing is available for analysis.
And maybe is the input voltage (1Vac) also to high for the Muses already. It has unbalanced in/outputs so I assume consumer levels too here (150mV).
You can try to attenuate the output from the pc to 150mVac and see what happens. Or make another attenuator with three resistors to change 1.12Vac to 150mV: one resistor of 97 ohms (100 // 3300) in series to a 15 ohm resistor (0.13x = 1/7.67).
From thereon, we can check the Muses for these level issues.
1Vac (rms) on an input (miniJack or RCA's), measured 1.12Vac with a multimeter (make a attenuater with a 12 ohm and a 100 ohm resistor for 1.00Vac).
This is applied to the volume board (Muses), but no regulation from -65 to -40 dB. At 0dB is the converter output (level 0) already 3.8Vac. Roughly times three is peak-peak: 14.5Vpp. The amp can handle +/-12Vpp, so that's still save.
What is the output level of the Muses?
The converter is an unbalance-balanced converter. I see 10k and 2k2 resistors alongside the dual opamps. The amplification can be set at 10k/2k2= 4.5x.
3.8Vac / 4.5x = 840mVac, which is acceptable. The amplification is a bit high. I think the converter is to be used for line level to pro level conversion, that's ~150mV to ~775mV (5.2x).
If the output from the Muses is high, the output from the converter is high. But this can be modified... if a circuit drawing is available for analysis.
And maybe is the input voltage (1Vac) also to high for the Muses already. It has unbalanced in/outputs so I assume consumer levels too here (150mV).
You can try to attenuate the output from the pc to 150mVac and see what happens. Or make another attenuator with three resistors to change 1.12Vac to 150mV: one resistor of 97 ohms (100 // 3300) in series to a 15 ohm resistor (0.13x = 1/7.67).
From thereon, we can check the Muses for these level issues.