4 ohm speakers

[Plevigne]

Just picked up psb stratus gold i's and denon avr3803ci receiver. My question is can i use this receiver as a preamp and add 2 amps to power the pbs 4 ohm speakers?

 

[MaxInValrico]

does the receiver have pre-outs?

 

[-Jim-]

Yes you can as the Denon avr3803ci receiver has pre-outs. But why not try using the Denon on it's own first?

 

[Trebdp83]

 

[-Jim-]

The AVR-3803CI is a bit different than the AVR-3803.

 

[Verdinut]

Just picked up psb stratus gold i's and denon avr3803ci receiver. My question is can i use this receiver as a preamp and add 2 amps to power the pbs 4 ohm speakers?

Did you try using the receiver to drive the PSB speakers? If your listening distance from the speakers is within 8 feet and you don't listen at high volumes, it is quite possible that the 3803CI is sufficient. However, if you find that it sounds like it struggles to drive those PSB Stratus Gold loudspeakers, sure you can use external amplification for your left and right front channels. Then, you would only need a stereo power amplifier to drive them.

Those Stratus speakers have a moderately high sensitivity, and their impedance does not dip below 4 ohms according to the manufacturer. So everything depends on your listening preferences and your listening distance. Should you intend to get a power amp for the external amplification, let us know and we shall be pleased to make you some recommendations.

 

[TLS Guy]

Just picked up psb stratus gold i's and denon avr3803ci receiver. My question is can i use this receiver as a preamp and add 2 amps to power the pbs 4 ohm speakers?

I would absolutely use a good external 2 channel power amp to drive those speakers.

This is the impedance curve of your speakers.

So the impedance is below four ohms, in the region where most power is required. In addition at 40 Hz where the impedance is four ohms, the phase angle is -45 degrees. By any reckoning those speakers are at the difficult load end of the spectrum.

The power amps in receivers are just not very good and getting worse.

Do not focus on amp distortion. If THD is below 0.1% an probably 0.2% further reductions in THD are irrelevant. There are much more important specs, never included in the spec sheet. The most significant spec. for receivers, is that their specification into a four ohm load is not specified. So that means you can do no wrong in assuming the power amps are junk.

Why, because any decent speaker is four ohm. In order to properly account for the full space half space transition, to stop the speaker sounding lousy you have to halve the impedance of the speaker below this transition, which will be in the 500 to 600 Hz range for most speakers. So that will double requirements for power in that pass band.

Absent active speakers with amps inside, that means you have to halve the impedance. Now if you have an impedance above 8 ohms above the transition frequency, then the speakers will score badly on its sensitivity spec.

So that is why any amp, including receiver amps, MUST be specified into four ohms. Not doing so is dishonest. The purchases therefore should correctly assume that if a manufacturer will not quote a four ohm spec. then he is pedaling junk.

You can see full test results of your speakers here. The measurement indicate they are very good speakers. They deserve driving from an amp of commensurate quality. Receiver amps are not of commensurate quality.

 

[BoredSysAdmin]

This is SoundAndVisio testing the amp on AVR-3808CI. They did test only at 8ohms, but the amp performance shows massive resources.

Denon AVR-3808CI A/V Receiver HT Labs Measures

HT Labs Measures: Denon AVR-3808CI A/V Receiver Five channels driven continuously into 8-ohm loads: 0.1 percent distortion at 118.9 watts 1 percent distortion at 138.0 watts All channels driven continuously into 8-ohm loads: 0.1 percent distortion at 113.5 watts 1 percent distortion at 130.7...

www.soundandvision.com

This graph shows that the AVR-3808CI’s left channel, from CD input to speaker output with two channels driving 8-ohm loads, reaches 0.1 percent distortion at 186.7 watts and 1 percent distortion at 210.9 watts. Into 4 ohms, the amplifier reaches 0.1 percent distortion at 238.9 watts and 1 percent distortion at 277.3 watts.

So, 3808CI has a great (for a receiver) amp and it is absolutely rated to work with 4ohm loads:

RC: AVR-3808CI @ 4ohms

Dynamic power: 210 W x 2ch (4 Ω/ohms)

https://downloads.denon.com/documentmaster/us/avr-3808ci-om-e_404a.pdf

 

[BoredSysAdmin]

bottom like, as @-Jim- said well above, before buying an external amp, why not try the Denon first?

 

[Trebdp83]

The AVR-3803CI is a bit different than the AVR-3803.

Yeah, missed that. Thought he should upgrade. Still do.

 

[lovinthehd]

This is SoundAndVisio testing the amp on AVR-3808CI. They did test only at 8ohms, but the amp performance shows massive resources.

Denon AVR-3808CI A/V Receiver HT Labs Measures

HT Labs Measures: Denon AVR-3808CI A/V Receiver Five channels driven continuously into 8-ohm loads: 0.1 percent distortion at 118.9 watts 1 percent distortion at 138.0 watts All channels driven continuously into 8-ohm loads: 0.1 percent distortion at 113.5 watts 1 percent distortion at 130.7...

www.soundandvision.com

So, 3808CI has a great (for a receiver) amp and it is absolutely rated to work with 4ohm loads:

RC: AVR-3808CI @ 4ohms

Dynamic power: 210 W x 2ch (4 Ω/ohms)

https://downloads.denon.com/documentmaster/us/avr-3808ci-om-e_404a.pdf

3808 is more powerful than the 3803 the OP has, tho. Not that something like TLS' Quad 909's specs per Quad are all that impressive either....

 

[Verdinut]

One more proof that you cannot trust what several loudspeaker manufacturers publish for their speakers. PSB did specify a minimum value of 4 ohms and that mislead me for the above post of mine.

I agree with TLS Guy in that the OP would have a real advantage with external amplification, taking into account that the impedance goes down to below 3 ohms at around 100 Hz combined with a -60° phase angle at around 50 Hz. I suspect that there is a strong possibility that the AVR might go into protection mode when the Stratus Golds are driven to some peak SPL.

 

[Eppie]

I can understand the confusion with the 3803CI vs 3808. If you search on 3803CI Google pops up a bunch of 3808 articles. Very little info out there on the 3803CI. If you add "-AVR-3808CI" then Google filters out the 3808 links (the minus in front acts as a "not"). Very few links returned with that filter.

 

[PENG]

The 4 ohm rated thing is sort of a misnomer.
The fact is, whether the 3803 can do a good job with the PSB Golds would depend on the OP's listening habit.

So as usual, I would suggest the OP to use an online calculator to figure out his power need. If thecalculator says you only need 15W to get 10 dB below reference with one speaker, then the 3803 will have at least 6 to 9 dB headroom for Stereo listening.

That' s based on maths and electrical theory, not myths.

 

[PENG]

I have been comparing my purifi amp, Halo A21 and the internal amp of the AVR-X4400H all afternoon and would love to say the AVR amps are junk as TLSGuy might want to call them but that's not my findings. In DBT I would bet 2 to 1 that no one, including TLSGuy can telll them apart.

That being said, I have been comparing them using analog inputs and direct mode. When I used the Denon to stream with HEOS, it didn't sound as good but it's all sighted test, and maybe I was doing something wrong so I need to do something troubleshooting before concluding anything.

In me experience, some avr amps such as my x4400h, if used well within their power limit, could sound as good as separate amps such as mine, if people would give them a chance without any preconception of any sort.

By the way, a point about the so called 8 ohm or 4 ohm rating, consider one fact/(or myth?) that one can easily appreciate: All else being equal, a 140W 8 ohm, 90 W 4 ohm rated amp is clearly more capable and dynamic than a 75 W so call 4 ohm rated amp for real world classical and jazz music, can we agree with that?

 

[TLS Guy]

I have been comparing my purifi amp, Halo A21 and the internal amp of the AVR-X4400H all afternoon and would love to say the AVR amps are junk as TLSGuy might want to call them but that's not my findings. In DBT I would bet 2 to 1 that no one, including TLSGuy can telll them apart.

That being said, I have been comparing them using analog inputs and direct mode. When I used the Denon to stream with HEOS, it didn't sound as good but it's all sighted test, and maybe I was doing something wrong so I need to do something troubleshooting before concluding anything.

In me experience, some avr amps such as my x4400h, if used well within their power limit, could sound as good as separate amps such as mine, if people would give them a chance without any preconception of any sort.

By the way, a point about the so called 8 ohm or 4 ohm rating, consider one fact/(or myth?) that one can easily appreciate: All else being equal, a 140W 8 ohm, 90 W 4 ohm rated amp is clearly more capable and dynamic than a 75 W so call 4 ohm rated amp for real world classical and jazz music, can we agree with that?

I made the point that the distortion spec. is not very relevant, as pretty much all have inaudible distortion. It is physical design that counts, and how much heat the devices make, and how hot the devices get. The problem with receivers is that the amps are packed in, the power transistors are puny and always single, instead of doubled or preferably tripled.

When an amp power transistor short circuits and throws the receiver into protection, then distortion figures are irrelevant, as distortion is then zero, as there is no output to measure.

If you are running 11 or more amps, significant heat is produced. There is no getting round it. There needs to be a whole change off approach. The best change is to have the amps in the speakers. That would produce a massive improvement in SQ.

With the cost of AV equipment now, reliability has to improve. Car audio systems hardly ever fail, and they have multiple power amps and DSP. Considering the limitations of the car environment, modern car audio systems are just incredible. We need to import some car audio engineers into the AV design.

Things currently are nowhere near as good as they should be and need to be. That goes for SQ and reliability. The fact needs to be squarely faced, that things need to change.

 

[PENG]

We need to import some car audio engineers into the AV design.

Things currently are nowhere near as good as they should be and need to be. That goes for SQ and reliability. The fact needs to be squarely faced, that things need to change.

May be we need more good class D amp designers such Bruno Putzeys.

I just compared my new Purifi amp with the Halo A21, almost the same power output into 4/8 ohms but the Purifi has a 2 ohm rating as well

These two amps have practically the same rated output into 4 ohms, the little one runs much cooler too. It will likely be more reliable too, and has a rating for 2 ohms as well.

The size and weight difference is huge, the Purifi is about 1/6 the size (volume), and the A21 is 6.7 times heavier.

Class D is future based on size, weight, and heat.

 

[TLS Guy]

May be we need more good class D amp designers such Bruno Putzeys.

These two amps have practically the same rated output into 4 ohms, the little one runs much cooler too. It will likely be more reliable too, and has a rating for 2 ohms.

View attachment 50657

I agree with you about that. Class D amps have now come of age. Current receiver design is just lousy engineering and lacks any semblance of elegant design.

Design needs to move to 19" rack based components.

You would have pre/pro case with power supply, and plug in the units you need, like phono preamp, processor module, streaming module etc.

Then you would have power amps case and just plug in the amps you need. So two or 2.1, three for 3.1 all the way up to 13 amp modules.

If you had active speakers, you would just need the pre/pro case.

Things need to change fast. What we have now is just unacceptable on so many levels, and is bad design and execution.

 

[PENG]

I agree with you about that. Class D amps have now come of age. Current receiver design is just lousy engineering and lacks any semblance of elegant design.

Design needs to move to 19" rack based components.

You would have pre/pro case with power supply, and plug in the units you need, like phono preamp, processor module, streaming module etc.

Then you would have power amps case and just plug in the amps you need. So two or 2.1, three for 3.1 all the way up to 13 amp modules.

If you had active speakers, you would just need the pre/pro case.

Things need to change fast. What we have now is just unacceptable on so many levels, and is bad design and execution.

And I agree with you AVR amps almost always use single output devices, but that is not necessarily a disadvantage. In fact a single 15 A (most D+M (the AVR-X3X00, SR6000/7000/8000) and Y (RX-A20X0 and higher series are 15 A rated), may arguable be better than two 8 A devices in parallel because there would be no issues of sharing between the two that may cause thermal runway issues if not designed well enough.

Separate power amps obviously more often have two output devices in parallel if they are truly 4 A rated and are rated more than 100 W into 8 ohms.

I can't argue the point that with so many power amps jammed into one box, AVRs will inherently be less reliable for owners who don't take precautionary measures. That's why if and when I suggest the AVR route I would emphasize the importance of first figuring out the estimated power need based on the individual's listening habits and under the worst case scenario, and then I would also recommend the use of a $20 quiet infinity fan.
The reality is, not a lot of HT users have the kind of budget and knowledge that you have, so I don't think we should shy way from suggesting AVRs to a lot of users on a budget and may not have the real estates for more multiple boxes options.

 

[Plevigne]

does the receiver have pre-outs?

Yes, and I'd like to bi-amp these speakers.