Connect CD player to Power Amp

MrCool78 · « **on:** 9 Jun 2006, 05:13 am »

Can anyone give me an input:
I have universal cd player Marantz DV 7600, and power amp Audio Refinement Multi 2, this amp has gain input volume for each channel, now my question is can I connect my CD player to power amp straight without pre amp? my audio output cd player is 2vrms and I don't want blow up my speaker if not right

Cheers

mjosef · « **Reply #1 on:** 9 Jun 2006, 06:57 am »

No problem...once you have a volume(gain) control before your amplification stage you are good to go...

warnerwh · « **Reply #2 on:** 9 Jun 2006, 07:00 am »

You have to have something in front of your amp to adjust the voltage from your cd player. Typical cd players output 2v. Most power amps need less than that for full output. So either a cd player with a volume control built in or a dac with a volume control is required to go without a preamp or a passive device. If you don't you will blow your speakers more than likely.

Bob Reynolds · « **Reply #3 on:** 9 Jun 2006, 03:33 pm »

My guess is that the level adjustments you speak of are for balancing the the two channels and are not intended to be used as a "stereo" volume control. I assume they are located on the back of the amp.

Get yourself a $100 NHT Passive Volume Control from here:

http://www.listenup.com/servlet/UpdateEngine/?FUELAP_SITEDBID=SITE_-66&FUELAP_OP=FUELOP_NewScreen&PAGE_ID=LUPAGE_60134&DP_ID=LISTENUP_DP_21769752&SECTION_ID=LUPAGE_60134&FUELAP_TEMPLATENAME=lu_product&

-- Bob

JLM · « **Reply #4 on:** 10 Jun 2006, 10:12 am »

Yes your amps probably have "trim pots". I had an amp with trim pots that I tolerated only briefly (located on the back, had to balance channel volumes by ear).

Most volume controls on CDPs are very rudimentary. My older Sony XA20ES has one. At maximum volume everything is right, but as you decrease the volume the loudest signals are compressed.

Seems like what you're after is a passive pre-amp. Channel Islands Audio and Bent Audio here at AC offer a couple versions.

A better alternative may be to move into PC based sources. Squeeze Box and Olive both have digital volume controls that you can control via remote control. When modded sound quality is excellent with either. If your want your entire libary ripped the SB works well, but requires a PC for storage. The Olive products are stand-alone and include a CDP, but have smaller HD capacities.

MrCool78 · « **Reply #5 on:** 13 Jun 2006, 03:37 am »

Hi Guys
Thanks for the inputs.
Frankly i have my own active pre amp but I forgot to state on my first post, which is i'm using it now. the reason why I wanted to know because i heard from some people direct connection from cd player to power amp is better than from cd player to preamp and power amp, is that true or depends on the components itself?
so since I'm not too sure what's on the back of my power amp, it's gain input or just volume control to balancing the channels, I didn't want take a risk to try it and blow up my speakers.
Sorry now I have some stupid questions:
1) What make it difference using passive preamp or active preamp in my case, will it make sound better??

2) Let's say that power amp has a volume control, why the cd player still needs a passive preamp to control the volume or because typical cd player has audio output 2V so more likely to connect it to power amp straight needs less than 2V audio output, to use any power amp without passive/active preamp??

Cheers

Gordy · « **Reply #6 on:** 13 Jun 2006, 05:00 am »

Hi MrCool

You needn't worry about the safety aspect of your amps gain controls, they are fine to use, you may not have a very fine control and they will be a pita to use though...

In general, passive preamp is one that does not have any gain, it simply attenuates whatever signal is passed to it from your front end unit. An active preamp will have circuitry which can add some gain to the signal, typically somewhere between 6dB and 18dB I believe. Which sounds best or most natural to you is a matter of personal taste and some experience and experimentation with all the various types of passive and active circuits!!!

You only need (or want) one volume control in the system, I think Warner just missed where you stated that the amp had gain controls already.... if I'm following all this correctly

Bob Reynolds · « **Reply #7 on:** 13 Jun 2006, 03:31 pm »

Quote from: MrCool78

Hi Guys
Thanks for the inputs.
Frankly i have my own active pre amp but I forgot to state on my first post, which is i'm using it now. the reason why I wanted to know because i heard from some people direct connection from cd player to power amp is better than from cd player to preamp and power amp, is that true or depends on the components itself? So since I'm not too sure what's on the back of my power amp, it's gain input or just volume control to balancing the channels, I didn't want take a risk to try it and blow up my speakers.
Sorry now I have some stupid questions:
1) What make it difference using passive preamp or active preamp in my case, will it make sound better??

2) Let's say that power amp has a volume control, why the cd player still needs a passive preamp to control the volume or because typical cd player has audio output 2V so more likely to connect it to power amp straight needs less than 2V audio output, to use any power amp without passive/active preamp??

Cheers

Many audiophiles have the belief that less "stuff" in the signal path leads to better sound. So, if CD is your only source and it has a level control, then you could omit the preamp. What type of level control is in the CD player is important as is how it is implemented. If the level control is done in the analog domain, then it could be just as good or poor as a preamp. If the level control is done in the digital domain, then you really need to know how it is implemented. The trick is digital attenuation without losing information.

1) As Gordy explained, you could try both to see which one you prefer. It's possible that an inexpensive passive attenuator would sound better than an inexpensive active preamp. If you have short ICs and the input sensitivity of your amp is less than the voltage output of your CD player, then passive will work OK.

2) I know the Decware tube amps have an input attenuator. If your amp has two level controls on the back, then I'm almost 100% sure they are trim pots for balancing the two channels. Look at the back of the Parasound Halo A21 amp http://www.parasound.com/halonew/A21back.php as an example.

Since the input sensitivity of most amps is less than the voltage ouput of most CD players, there is no requirement for gain from an active preamp. Note that the active preamp does more than just provide potential gain, it also isolates the output impedance of the source component from the input impedance of the amp. It also buffers the signal so that driving long ICs is possible. But, regardless of that, in general attenuation is required between the source and amp.

-- Bob