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Does JBL 305p/306p need balanced DAC?

king0188

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Hello everyone, ASR is interesting , I can learn much from here.
Here's my first thread:
I want to buy JBL 305p/306p ( to connected to my TV) and I need a DAC.
The question is does the DAC have to be balanced output (XLR or TRS) ? Or just RCA output is OK?
Any recommend DAC? Like SMSL SU-1/D-6/D-6s?
Sorry for my poor English:D:D
 

staticV3

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Hi @king0188!

The JBL 305p/306p does not need a DAC with balanced (differential) output.

With the right cables (link), you can use a regular RCA DAC as well.

I'd give the SMSL PS100 a try. Since it has an HDMI ARC input, you can continue using your TV's remote to control the volume.

With other DACs that you connect via Toslink or Coax, you'd have to use their remote to control volume as most TVs will lock their volume when you use digital audio output.
 

DVDdoug

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If you have RCA cables/connectors this will work.

It's always OK to connect an unbalanced signal to a balanced input. (Balanced outputs don't always work properly into unbalanced inputs, but usually they do.)


I found the owner's manual online:

9. XLR INPUT – Connect professional equipment to this connector using a balanced XLR plug.

10. 6MM (¼") INPUT – Connect professional equipment to this connector using a 6mm (¼") balanced plug. Connect consumer equipment to this connector using a 6mm (¼") unbalanced plug.
 

staticV3

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If you have RCA cables/connectors this will work.
It will work, but will negate the XLR input's CMRR, increasing the risk of ground-loop induced noise.

In contrast, the Monoprice cable I linked preserves the CMRR even with RCA sources.
 
OP
king0188

king0188

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It will work, but will negate the XLR input's CMRR, increasing the risk of ground-loop induced noise.

In contrast, the Monoprice cable I linked preserves the CMRR even with RCA sources.
Thanks for your advice!
You say "It will work, but will negate the XLR input's CMRR", do you mean when the cable (XLR to RCA) is not carefully chosen, it will affect sound quality?
 
OP
king0188

king0188

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If you have RCA cables/connectors this will work.

It's always OK to connect an unbalanced signal to a balanced input. (Balanced outputs don't always work properly into unbalanced inputs, but usually they do.)


I found the owner's manual online:
Thanks for your owner's manual link
 
OP
king0188

king0188

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It will work, but will negate the XLR input's CMRR, increasing the risk of ground-loop induced noise.

In contrast, the Monoprice cable I linked preserves the CMRR even with RCA sources.
By the way, I heard someone say when you use unbalanced signal(RCA) to input JBL 305p, you will lose something(such as “Dynamic Range”)
Is it true?
 

staticV3

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You say "It will work, but will negate the XLR input's CMRR", do you mean when the cable (XLR to RCA) is not carefully chosen, it will affect sound quality?
You may get mains hum and other noises with poorly constructed cables. It is not guaranteed.

I heard someone say when you use unbalanced signal(RCA) to input JBL 305p, you will lose something(such as “Dynamic Range”)
Is it true?
You will not lose dynamic range.
 

Tom C

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I have 306P. I like them a lot. My only regret is not buying 308P instead, which I would now consider to be worth the extra money. But size and budget are sometimes more important.
This is a screen shot from the owner manual:
IMG_0141.jpeg

I drew a circle around a control switch in the back. You need to select the correct setting for your situation. Regardless of the wires you use, if your DAC has RCA connectors, you want the switch in the -10dBv position. If your DAC has XLR connectors, you want the switch in the +4dBu position.
The reason for this is that RCA expected max voltage is in the 1 to 2 volt range for full output. The expected max voltage for XLR is around 4 volts for full output, typically. Exceptions to these rules of thumb exist, but for home (consumer) use these guidelines are useful and valid. It’s important to have the setting correct to get the best possible sound, because you don’t want to overdrive the input of the built-in amp, or, conversely, you won’t be able to drive the speaker’s amp to full output.
 
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king0188

king0188

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I have 306P. I like them a lot. My only regret is not buying 308P instead, which I would now consider to be worth the extra money. But size and budget are sometimes more important.
This is a screen shot from the owner manual:
View attachment 335537
I drew a circle around a control switch in the back. You need to select the correct setting for your situation. Regardless of the wires you use, if your DAC has RCA connectors, you want the switch in the -10dBv position. If your DAC has XLR connectors, you want the switch in the +4dBu position.
The reason for this is that RCA expected max voltage is in the 1 to 2 volt range for full output. The expected max voltage for XLR is around 4 volts for full output, typically. Exceptions to these rules of thumb exist, but for home (consumer) use these guidelines are useful and valid. It’s important to have the setting correct to get the best possible sound, because you don’t want to overdrive the input of the built-in amp, or, conversely, you won’t be able to drive the speaker’s amp to full output.
Thanks a lot! This is useful
 
OP
king0188

king0188

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I'd give the SMSL PS100 a try. Since it has an HDMI ARC input, you can continue using your TV's remote to control the volume.

With other DACs that you connect via Toslink or Coax, you'd have to use their remote to control volume as most TVs will lock their volume when you use digital audio output.

I find PS100(or SU-1) don't have volume control function, when I connect:
TV >> PS100 >> JBL 305p
Is it better to turn TV‘s volume to 100%, and then use JBL 305p's knob to control volume? I have seen someone say TV‘s volume control would loose sound quality.
I don't know if that's true.
 

staticV3

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I find PS100(or SU-1) don't have volume control function, when I connect:
Did you turn on HDMI-CEC on your TV? (Sometimes called SIMPLINK).
This option is required for your TV to be able to send audio commands to the PS100 via HDMI.

Is it better to turn TV‘s volume to 100%, and then use JBL 305p's knob to control volume? I have seen someone say TV‘s volume control would loose sound quality.
I don't know if that's true.
Unless you hear additional hiss out of your JBLs, it does not matter.
 

Philbo King

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I find PS100(or SU-1) don't have volume control function, when I connect:
TV >> PS100 >> JBL 305p
Is it better to turn TV‘s volume to 100%, and then use JBL 305p's knob to control volume? I have seen someone say TV‘s volume control would loose sound quality.
I don't know if that's true.
It depends on the TV. Feed the TV output to a (virtual PC) oscilloscope and look for clipping, or better yet, a spectrum analyser app/plugin and look for an abrupt rise in harmonics as you vary the volume. Sometimes the audio circuits in a TV do better at 70% than 100%. And sometimes the HDMI audio level is completely unaffected by the TVs volume setting.
 
OP
king0188

king0188

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I have seen someone say TV‘s volume control would loose sound quality
The source is here from HiFiDIY Forum.
数字音量压缩会降低比特数,小音量严重损失信号转换精度,毋庸置疑的。
如图所示:图一原始16位数据满格(最大)音量,图二数字压缩音量以后损失数据,图三进一步压缩音量严重损失数据
translate to English
Digital volume compression will reduce the number of bits, small volume seriously cause loss of signal conversion accuracy, there is no doubt.
As shown in the figure: Figure 1 raw 16-bit data full cell (maximum) volume, Figure 2 digital compression volume after the loss of data, Figure 3 further compression volume serious loss of data.
bbs.hifidiy.net_forum.php.jpg
bbs.hifidiy.net_forum_1.php.jpg
bbs.hifidiy.net_forum_2.php.jpg
 

staticV3

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The source is here from HiFiDIY Forum.

translate to English

View attachment 336822View attachment 336823View attachment 336824
It sounds very dramatic, but this loss in bit depth/resolution is usually meaningless as those lost bits are below the noise floor of your Amplifier and environment anyway.

If you can hear additional hiss out of your speakers once you plug the DAC into your Amp, then it's worth thinking about using analog attenuation instead of digital.

If not, then those lost bits are irrelevant.
 
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