Hi,
Is there any chance of an internal photo?
Also, when you use the mute button, is there any noise out of the speakers?
Many thanks
Barry
There should not be noise from mute button ( this is a hard bypass).
Spl is very serious pro gear ( the one i used in studio was. All the units i've seen. Deutsch Qualitat!). I't ll be difficult to see what is inside from a picture ( i presume it to be full smd multilayer pcb).
I looked for a schematic in my archive and web but for the moment no luck. As it is still on sale atm it may not be easy to source schematic without owning a unit.
The fact the attenuators are buffered and balanced is really great ( you can drive long lines with it and won't loose balanced out) and the one knob/one pushbutton approach is appealing to me.
Spl is very serious pro gear ( the one i used in studio was. All the units i've seen. Deutsch Qualitat!). I't ll be difficult to see what is inside from a picture ( i presume it to be full smd multilayer pcb).
I looked for a schematic in my archive and web but for the moment no luck. As it is still on sale atm it may not be easy to source schematic without owning a unit.
The fact the attenuators are buffered and balanced is really great ( you can drive long lines with it and won't loose balanced out) and the one knob/one pushbutton approach is appealing to me.
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Apogee internal adjustments
One of my friends has lent me a Rotel RB power amp for the vertical horn. Its input sensitivity is low, so I have changed the analogue output level jumpers from -10 dBV to + 4 dBU for only outputs 1 & 2.
Reading up these levels I found:-
-10 dBV = -7.7 dBU = 0.3 V [RMS].
1.78 dBV = + 4 dBU = 1.2 V [RMS].
Are there any drawbacks to doing this?
I've seen there is a daughter board to go onto the jumpers to give more adjustment - ROSETTA800CA - anyone got one of these?
The Rotel power amp has no input adjustment, but the other 3 power amps do.
I've used REW to get the balance between the different frequencies.
I still have SPL VOL8 as master volume control
Thanks in advance for your comments.
One of my friends has lent me a Rotel RB power amp for the vertical horn. Its input sensitivity is low, so I have changed the analogue output level jumpers from -10 dBV to + 4 dBU for only outputs 1 & 2.
Reading up these levels I found:-
-10 dBV = -7.7 dBU = 0.3 V [RMS].
1.78 dBV = + 4 dBU = 1.2 V [RMS].
Are there any drawbacks to doing this?
I've seen there is a daughter board to go onto the jumpers to give more adjustment - ROSETTA800CA - anyone got one of these?
The Rotel power amp has no input adjustment, but the other 3 power amps do.
I've used REW to get the balance between the different frequencies.
I still have SPL VOL8 as master volume control
Thanks in advance for your comments.
Attachments
Hi,
Nobody answered so i will:
From a technical point of view there is no issue running the rosetta outputs to different sensitivity ( it's why there is choice for them). If an isue could arise that would be from the Spl or the Rotel amp.
Spl being pro gear i would expect it's nominal level to be +4dbu so i would not expect any issue there ( check within manual).
What is the input sensibility of your Rotel amp (and input Z)?
This is where i could see an issue (about sensibility and potential overdrive of input).
The other issue being a mismatch in level for one of the voices wrt to the other. In other term a level mismatch messing with the outcome of filters.
If you want to be safe about it, you'll have to define a reference signal outlevel ( -10dbv seems wise) and from there determine how much attenuation is needed on the +4dbu output pair for the way to be correctly aligned to the others.
Then it is a just a matter of implementing an U pad ( 3 resistance attenuator) or T pad ( 5 resistance) for this +4dbu pair.
If you want to make things 'right' you need to know the input impedance of Rotel amp.
Uneeda Audio - Build your own attenuator pads
Basically this is what i've done with my 3 level attenuator i talked about previously.
Hope it is clear. If not PM me.
I'm surprised the Rosetta didn't had a trimmer to set the output. The ones i've seen had this iirc ( but i may mix up with another converter as i took care of many from different brands). Anyway, given it is an 'ancient' converter it might not be availlable anymore ( and knowing Apogee cost an arm and leg if available). The Lpad will work the same in practice ( there might be difference - i depend on how the attenuation is implemented within the Rosetta- but so tiny it won't matter in the end).
Nobody answered so i will:
From a technical point of view there is no issue running the rosetta outputs to different sensitivity ( it's why there is choice for them). If an isue could arise that would be from the Spl or the Rotel amp.
Spl being pro gear i would expect it's nominal level to be +4dbu so i would not expect any issue there ( check within manual).
What is the input sensibility of your Rotel amp (and input Z)?
This is where i could see an issue (about sensibility and potential overdrive of input).
The other issue being a mismatch in level for one of the voices wrt to the other. In other term a level mismatch messing with the outcome of filters.
If you want to be safe about it, you'll have to define a reference signal outlevel ( -10dbv seems wise) and from there determine how much attenuation is needed on the +4dbu output pair for the way to be correctly aligned to the others.
Then it is a just a matter of implementing an U pad ( 3 resistance attenuator) or T pad ( 5 resistance) for this +4dbu pair.
If you want to make things 'right' you need to know the input impedance of Rotel amp.
Uneeda Audio - Build your own attenuator pads
Basically this is what i've done with my 3 level attenuator i talked about previously.
Hope it is clear. If not PM me.
I'm surprised the Rosetta didn't had a trimmer to set the output. The ones i've seen had this iirc ( but i may mix up with another converter as i took care of many from different brands). Anyway, given it is an 'ancient' converter it might not be availlable anymore ( and knowing Apogee cost an arm and leg if available). The Lpad will work the same in practice ( there might be difference - i depend on how the attenuation is implemented within the Rosetta- but so tiny it won't matter in the end).
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Hi, thanks for replying.
Rotel RB-971 mkII manual states:-
Input Impedance / Sensitivity - 33 k ohms / 1.0 volt.
SPL has nominal level +4dBU
I'll read more thoroughly your reply and PM if I have any questions.
Thanks
Barry
Rotel RB-971 mkII manual states:-
Input Impedance / Sensitivity - 33 k ohms / 1.0 volt.
SPL has nominal level +4dBU
I'll read more thoroughly your reply and PM if I have any questions.
Thanks
Barry
ADC on the Apogee is not working on 7 out of 8 channels and the last channel has low output & is distorted.
I can still play music from my NAS drive.
In the short term, I'm looking for a small ADC to connect into Lynx card as shown on the schematic.
I've looked at the Apogee PCB and there are no obvious signs of damage - not that I have the knowledge or ability to repair it.
Either new or second hand suggestions are welcome
Thanks
Barry
I can still play music from my NAS drive.
In the short term, I'm looking for a small ADC to connect into Lynx card as shown on the schematic.
I've looked at the Apogee PCB and there are no obvious signs of damage - not that I have the knowledge or ability to repair it.
Either new or second hand suggestions are welcome
Thanks
Barry
