I am in a DIY project of upgrading a 1967 BeoLab 700K receiver.Beomaster 700
I want to add a streaming module connected to the Line-IN (Tape) of the receiver. That way I can listen to the tuner or switch to the Tape IN for streaming music.
For the streaming module I use the Acrylic Up2Stream Mini v2. https://cdn.shopify.com/s/files/1/0072/6899/1049/files/Up2Stream_Mini_v2.pdf
When the Up2Stream is connected to the Tape IN of the receiver, the volume is lower then the volume when listening to the tuner. So when switching back to the tuner, the volume is very loud.
Obviously, the audio-out signal of the Up2Stream module needs some pre-amplification. I was advised to use the AD828 pre amp board for that. AD828 Datasheet and Product Info | Analog Devices
So I connected the Audio-out of the Up2Stream board, to the Audio-IN of the AD8282 Pre Amp board. Unfortunately, after testing I found out that the signal does not get amplified. At least not noticeable. When switching between Tape IN for streaming and tuner, the volume on the tuner is still much louder than on the Tape IN.
Question?
What is the right solution to solve this? Is the AD828 the wrong Pre Amp to use? Did I miss something? I am looking for advice, please let me know your suggestions.
PS.
For powering the Up2Stream Mini and the Pre Amp, I have added an isolated AC/DC converter. Isolated to prevent ground loop. So both boards are powered from one AC/DC converter. 3Pcs HLK-PM01 AC-DC 220V To 5V Mini Power Supply Module Intelligent Household Sw - US$10.87
FYI
I have added a PDF of the setup of my connections between the modules. See the attached PDF.
I want to add a streaming module connected to the Line-IN (Tape) of the receiver. That way I can listen to the tuner or switch to the Tape IN for streaming music.
For the streaming module I use the Acrylic Up2Stream Mini v2. https://cdn.shopify.com/s/files/1/0072/6899/1049/files/Up2Stream_Mini_v2.pdf
When the Up2Stream is connected to the Tape IN of the receiver, the volume is lower then the volume when listening to the tuner. So when switching back to the tuner, the volume is very loud.
Obviously, the audio-out signal of the Up2Stream module needs some pre-amplification. I was advised to use the AD828 pre amp board for that. AD828 Datasheet and Product Info | Analog Devices
So I connected the Audio-out of the Up2Stream board, to the Audio-IN of the AD8282 Pre Amp board. Unfortunately, after testing I found out that the signal does not get amplified. At least not noticeable. When switching between Tape IN for streaming and tuner, the volume on the tuner is still much louder than on the Tape IN.
Question?
What is the right solution to solve this? Is the AD828 the wrong Pre Amp to use? Did I miss something? I am looking for advice, please let me know your suggestions.
PS.
For powering the Up2Stream Mini and the Pre Amp, I have added an isolated AC/DC converter. Isolated to prevent ground loop. So both boards are powered from one AC/DC converter. 3Pcs HLK-PM01 AC-DC 220V To 5V Mini Power Supply Module Intelligent Household Sw - US$10.87
FYI
I have added a PDF of the setup of my connections between the modules. See the attached PDF.
Please post a link to your pre-amp board.
I found this -
'R7 and R5 are the gain set resistances (delivery gain default is about 5). However you can change the audio gain according to your needs by changing these two resistors from 5k to 47K, The greater the resistance, the higher the audio gain will be. If you are using radial lead resistors, then remove the original chip resistors from the circuit board and solder the leads into both sides of the pads provided on the circuit board.'
However, I am surprised the Up2Stream is not loud enough on its own. Especially given 'line in' on older (say pre-1980s) electronics is generally more sensitive than on more modern units.
Hopefully someone with direct experience of the Up2Stream will chime in.
I found this -
'R7 and R5 are the gain set resistances (delivery gain default is about 5). However you can change the audio gain according to your needs by changing these two resistors from 5k to 47K, The greater the resistance, the higher the audio gain will be. If you are using radial lead resistors, then remove the original chip resistors from the circuit board and solder the leads into both sides of the pads provided on the circuit board.'
However, I am surprised the Up2Stream is not loud enough on its own. Especially given 'line in' on older (say pre-1980s) electronics is generally more sensitive than on more modern units.
Hopefully someone with direct experience of the Up2Stream will chime in.
does the app you are using have a volume control? Does adjusting the volume on your phone or tablet have an effect?
I used an old Note book laptop to stream music with foobar. I have the foobar remote app on my phone and tablet. I can adjust the volume on my phone or tablet which effects the stereo volume.
I used an old Note book laptop to stream music with foobar. I have the foobar remote app on my phone and tablet. I can adjust the volume on my phone or tablet which effects the stereo volume.
AD828 datasheet
Thanks for responding guys!
I am also surprised the output of the Up2Stream is low. But I have experienced that several times already in different projects.
The datasheet of the AD828 pre amp board is in my post. But here it is again:
AD828 Datasheet and Product Info | Analog Devices
Hope to hear your suggestions!
Thanks for responding guys!
I am also surprised the output of the Up2Stream is low. But I have experienced that several times already in different projects.
The datasheet of the AD828 pre amp board is in my post. But here it is again:
AD828 Datasheet and Product Info | Analog Devices
Hope to hear your suggestions!
Thanks for responding guys. Yes, I am also surprised about the lower volume.
Concerning the AD828 pre amp board, the datasheet link is in my original post. But here it is again:
AD828 Datasheet and Product Info | Analog Devices
Concerning the AD828 pre amp board, the datasheet link is in my original post. But here it is again:
AD828 Datasheet and Product Info | Analog Devices
Oh no it isn't!
You supply a link to the chip data sheet; not your pre-amp that implements it.
Nowhere can I find a spec for the output level of the Up2Stream.
To all that expected me to have the details in the electronics, excuse me.
I am an DIY audio enthousiast and like to build and explore. But I am not educated or trained in electronics. Just hope for help and some advise.
Concerning the AD828, I have unfortunately very limited information about this pre amp board. This is the PCB I have: DC 5V-15V 9V 12V AD828 Opamp Stereo Preamplifier Module Audio Preamp Amplifier 699914002363 | eBay
For the Up2Stream I will try to find info about the output level.
I am an DIY audio enthousiast and like to build and explore. But I am not educated or trained in electronics. Just hope for help and some advise.
Concerning the AD828, I have unfortunately very limited information about this pre amp board. This is the PCB I have: DC 5V-15V 9V 12V AD828 Opamp Stereo Preamplifier Module Audio Preamp Amplifier 699914002363 | eBay
For the Up2Stream I will try to find info about the output level.
The gain of the preamp is set by two resistors. So, you can provide links all you want, but as long as you don't provide the resistor values, no way can anybody say anything about the gain.
Even with little experience, you should be able to check the board layout and figure out or measure the resistor values, and to which opamp pins they are connected. It should look like something like the attached. You can find the pin numbers in the opamp data sheet.
You've got to start somewhere if you are serious about this.
Jan
Even with little experience, you should be able to check the board layout and figure out or measure the resistor values, and to which opamp pins they are connected. It should look like something like the attached. You can find the pin numbers in the opamp data sheet.
You've got to start somewhere if you are serious about this.
Jan
Attachments
I also looked and could find no output levels stated. Still, most DACs are going to output 2V or close to it. No Bluetooth interface I've ever used had a low level.
As suggested earlier, look for a volume control somewhere that you haven't noticed. And I have found on most vintage gear the radio tuner is LOUD. Much of that is because radio stations dynamically compress the hell out of the signal to make it loud all the time. Hopefully, your music streams aren't so smashed into the loud zone.
As suggested earlier, look for a volume control somewhere that you haven't noticed. And I have found on most vintage gear the radio tuner is LOUD. Much of that is because radio stations dynamically compress the hell out of the signal to make it loud all the time. Hopefully, your music streams aren't so smashed into the loud zone.
Think again.
This is a +5V single supply fed device, NO WAY it will ever put out 2V RMS or anything approaching that.
FWIW 2V RMS=5.66Vpk , more than available supply.
It will struggle to put out even the 750mV RMS suggested since THIS modern source is fed 5V +V, and it will have no headroom available IF doing so.
I would expect typical Phone headphone level, say 100 to 200mV RMS, tops.
So not surprised to find output does not properly drive that fine old receiver Tape input and to boot the 5V fed 828 preamp board will also be ill suited to that.
Start by getting/kludging +15V to feed that preamp board and PLEASE provide current R5/R7 values.
PLEASE.
get a good loupe, good illumination and read the values printed on them and/or measure them onboard with a modern multimeter; if the schematic is the basic one I IMAGINE
(since not even original manufacturer bothered to supply it ) , value should be readable in-circuit (with board unpowered, of course).
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Not "expect". We are telling you the clues needed to move forward.
That seems an obvious thing to link early in the question. And it would have saved "me" the chore of marking-up the only image you gave. In fact the key resistors are called out in the listing as gain-sets (except they call it "magnification").
If you feel that the default magnification is not appropriate, you can change the magnification, magnification adjustment is as follows:
R7, R5 is the magnification set resistance (delivery default is about 5 times the amplification, you can change according to their own need to enlarge the resistance can be selected from 5k-47k, the greater the resistance, the higher the magnification,.....)
The next question: 5X gain is a LOT for most hi-fi line amps. Why is it "signal does not get amplified. At least not noticeable" for you?
Attachments
No need to think again. No Bluetooth receiver I've ever used had a low enough output level to worry about. I do find the radio loud on many stations, but not all of them. The radio is usually louder than either the phono or aux inputs.
If you like, I can measure a Bluetooth receiver for you. I'd be curious to know what it outputs at full level. 2V? 1V? 0.7V?
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