Speaker level to line level converter; how bad the distortion is? (plus crazy idea)

I have a Denon integrated amp which has 'pre out' connections. On studying the circuit diagram I found that these actually come from the headphone output circuit vis a resistor network (basically a speaker to line level converter as described above). My first thought was - Why would anyone do that? Then I realised that the amps input sensitivity for general inputs is 150mV and these are basically sent straight to the input of the power amp section. The standard true preamp/power amp levels are around 1V. This arrangement saves them from needing to add a line buffer for the pre out connection.
But the point is that it seems to work O.K.
 
I had a few occasions where I would be using an Altec lansing mixer amplifier for reenforcing Barber Shop Quartets, Flamenco Guitar, Piano, Concert Harp,etc, in a Scottish Rite temple that didn't have a readily available line out. So I would build a quick and dirty voltage divider to knock the level down to feed my Ampex mixer using other mics to add ambience and make a sort of Stereo recording from a mono source. It worked really well and as the Mixer amp had less than .5% distortion or less 99% of the time the recordings came out quite well. From one of my recordings the performers had an LP made by Century Records. I think they order 5000 lp's back in the late 60's. I know it wasn't the Buffalo Bills, but I just can't recall right at the moment. I think they were from New Orleans.
 
What's the difference? I think that the Pyle device largely removes/gets away from the preamp noise you are referring to. But then again, maybe it doesn't. Like you said, maybe that's what's hyping the bass so much???
Probably. Since you stack pre amps as well as power amps, it increases the complexity of the system, adding more factors that can affect the sound. Have you try connecting the Sony AVR to the quad receiver's tape in instead of line in? If you use tape in, then you are bypassing all the volume control and tone controls of the vintage quad receiver. See if the bass is still hyped that way.


My quad receiver sounds better than my Sony AVR, so that's why I'm running the signal from the Sony AVR into the quad receiver. I still get all the HDMI switching functions provided by the Sony AVR, but get to listen to it through the vintage quad receiver.
Very interesting. What Sony AVR do you use? And with what quad receiver?
 
Anyway, isn't it interesting to see an audio myth being debunked by member's experience on this thread?

"Never use speaker level to line level connector, it causes distortion and ruins sound quality. It's only applicable in car audio, since sound quality in car is not paramount anyway. If you want to use external power amplifier, buy a proper receiver with pre-outs instead!"

Yes, that is one of audio dogmas that I firmly believed before this thread. But experience shared by TudorTurtle, JayBlok, Retrovert, Powertech, and twiii has shown that speaker level to line level converter is not necessarily detrimental to sound quality; at least not in audible level. Even hnash53 only experienced minor problem (boomy bass).

Nowadays, affordable AV receiver with pre-outs are getting scarcer. My Yamaha RX-V663 --a mid-tier receiver-- has pre-outs, but it is a thing from the past. I hope this information would be relieving to those wanting to use external power amplifier, but can only afford AVR without pre-outs. Thanks for the share.

Now, I hope this thread will not degenerate into flame war like my previous thread had. :( Let's just share your experience, and keep everything civil.
 
My Audiosource amps have speaker level input. I don't hear distortion. There is a significant hum...

It's definitely not a high-fidelity solution, at least in my case. I think there's a good reason they're not commonly used anymore, even in car audio applications.
 
JayBlok's photo shows R1 at 4.9 K Ohms and R2 at .430 K ohms, very close to what I used; 50 K ohms and .5 K Ohm, using this voltage divider:

speaker_to_line.gif


Like JayBlok mentioned, <$5

I would also put a 16 ohm (or actually anything between 10 and 20 ohms, depending on cost - cause I'm cheap) across the speaker terminals, in parallel with the voltage divider. This keeps the load on the supplying amp in spec for reliability issues. Use a min of 5 watts. With the voltage divider shown, Expect to see about 2.5 to 3 volts out of the amp to get about .25 volts at the line out point. With a 10 ohm load resistor, that is about 1 watt dissipated in the load. Higher value resistor will keep the load a bit lower. This should be a good sweet spot for most amps for distortion. A 16 ohm resistor will drop the power output down to about .5~.6 watts (less current draw at the same voltage).

Shelly_D
 
My Audiosource amps have speaker level input. I don't hear distortion. There is a significant hum..
I see. So there is potential hum problem.

Anyway, what model does your amplifier belong to? Interesting. This is the first time I read about an amplifier with speaker level input.


It's definitely not a high-fidelity solution, at least in my case. I think there's a good reason they're not commonly used anymore, even in car audio applications.[/QUOTE]
It is not, but for those whose AVR doesn't have pre-outs, it's still better than nothing, I guess.

Anyway, anyone ever heard about Behringer Ultra DI Pro DI800? It allows direct connection to speaker outputs with up to 3000 watts.
 
. Did you mean 5 kOhm and 0.5 kOhm, maybe?
My memory's a liar and my typing's bad. Went back and looked at the actual design. The divider within the crossover had R2 = 1 K Ohm, and R1 = 50 K Ohm. This was lowering the output of the bass frequency as it was passed to a powered woofer box, a unique use where a 50:1 was working best for that speaker & crossover.

Kresh,
The illustration is from the excellent doc, linked below. In the document he discusses using a 33:1 divider when using higher powered amps. Also discusses making an adjustable divider using a trimmer for R2.
http://www.epanorama.net/circuits/speaker_to_line.html
 
I would also put a 16 ohm (or actually anything between 10 and 20 ohms, depending on cost - cause I'm cheap) across the speaker terminals, in parallel with the voltage divider. This keeps the load on the supplying amp in spec for reliability issues.

Solid state amplifiers don't care about the load as long as it isn't too low. High impedance, or open circuit, is fine.
 
Solid state amplifiers don't care about the load as long as it isn't too low. High impedance, or open circuit, is fine.

Typically true. However, two points here. In operation, the user will need to set the volume of the source as well as setting the volume on the secondary amp. Some amps show better and finer control if there really is an expected load on the outputs. (Not all but some). The other point is that there have been some solid state amps that did go unstable without a load. Even if the amp is stable with no load, it would probably be more likely to meet or better its distortion rating with load. For the cost a couple of 5 watt resistors, why assume that the amp will be fine when you can insure it.

Shelly_D
 
Typically true. However, two points here. In operation, the user will need to set the volume of the source as well as setting the volume on the secondary amp. Some amps show better and finer control if there really is an expected load on the outputs. (Not all but some). The other point is that there have been some solid state amps that did go unstable without a load. Even if the amp is stable with no load, it would probably be more likely to meet or better its distortion rating with load. For the cost a couple of 5 watt resistors, why assume that the amp will be fine when you can insure it.

Ok, but the shunt resistor provides a load. What I think you are saying is that a low-impedance load is required for stability. I haven't researched this problem, but have seen enough poor design practices leading to oscillating amplifiers that I'd believe just about anything can occur when designers cut corners to save a few cents per unit.

All resistors, BTW, should be wire-wound to avoid noise. Carbon composite or carbon film will be adding noise and distortion. Metal film is fine, but wire-wound is even lower noise.
 
i used/have a pair
its so long ago that i dont remember why i used them
they were between a carver "the receiver" and some avr
they worked fine
they were scosche brand
they included a level control so you could balance the 2 sides if you needed
they are available at most auto sound places and are cheap like less than 20.00 cnd each
 
Probably. Since you stack pre amps as well as power amps, it increases the complexity of the system, adding more factors that can affect the sound. Have you try connecting the Sony AVR to the quad receiver's tape in instead of line in? If you use tape in, then you are bypassing all the volume control and tone controls of the vintage quad receiver. See if the bass is still hyped that way.



Very interesting. What Sony AVR do you use? And with what quad receiver?

Great idea on connecting to the tape in... I'll give that a try this evening.

I have a Sony STR-DH550. It's their basic model. There are some Integra HTRs for $150 that have zone outs and I've thought of going over to that HTR and use the zone out on it.

My quad is a Sanyo 3300KA. Certainly not one of the touted quad units of the 70s, I've A/B'd with a couple of Sansui's and honestly mine came out the winner by a long shot, according to these old ears.
 
I saw the headphone output of the first amp mentioned earlier, is the amp in question here missing that important feature? Usually a headphone output makes an excellent preamp output.
 
Same here, and that's what stirs my curiosity. I wonder if anyone has actually tried it.
I have in the past. I got my GFs son some decent little Sony bookshelf speakers and one of those mini bt amps as a desktop system. I had an old Kenwood powered SUB sitting around, but it didn't have a high pass input. RCA only. So I got one of the speaker out to line level converters used for car audio, and pretty much just spliced it into one of the channels speaker wire. It worked well enough. Although a sub probably won't display much on the way of distortion.
 
Great idea on connecting to the tape in... I'll give that a try this evening.

I have a Sony STR-DH550. It's their basic model. There are some Integra HTRs for $150 that have zone outs and I've thought of going over to that HTR and use the zone out on it.

My quad is a Sanyo 3300KA. Certainly not one of the touted quad units of the 70s, I've A/B'd with a couple of Sansui's and honestly mine came out the winner by a long shot, according to these old ears.
I made a mistake. :(

I forgotten tape-in is the same with line-in; the signal will still be processed by your quad receiver's preamp, it is still affected by volume control.

If your Sony AVR has tape-out, then you can connect it to your quad receiver. That way, the signal will be unaffected by the AVR's volume control and preamp; only your quad receiver control the volume. And perhaps it could reduce distortion.


I have in the past. I got my GFs son some decent little Sony bookshelf speakers and one of those mini bt amps as a desktop system. I had an old Kenwood powered SUB sitting around, but it didn't have a high pass input. RCA only. So I got one of the speaker out to line level converters used for car audio, and pretty much just spliced it into one of the channels speaker wire. It worked well enough. Although a sub probably won't display much on the way of distortion.
Ah yes, low frequency seems to be more immune to distortion.


Anyway, how about stereo imaging and sound stage? Has anyone ever noticed if both or either is adversely affected by speaker to line converter?
 
I made a mistake. :(

I forgotten tape-in is the same with line-in; the signal will still be processed by your quad receiver's preamp, it is still affected by volume control.

If your Sony AVR has tape-out, then you can connect it to your quad receiver. That way, the signal will be unaffected by the AVR's volume control and preamp; only your quad receiver control the volume. And perhaps it could reduce distortion.

That's ok... the real solution will be to find/buy a unit with pre outs or zone outs and send the signal from there to the Sanyo quad unit.

Since it's the bass that seems to be most affected, maybe I'll turn down the bass on the Sanyo and give a listen.
 
That's ok... the real solution will be to find/buy a unit with pre outs or zone outs and send the signal from there to the Sanyo quad unit.

Since it's the bass that seems to be most affected, maybe I'll turn down the bass on the Sanyo and give a listen.
So how is the result? I hope it's good.

Anyway, I'm thinking about Sansui QRX. They have excellent vario-matrix decoder/synthesizer, but they don't have pre-outs. Perhaps a good speaker level to line level converter would be a good thing in this scenario.
 
So how is the result? I hope it's good.

Anyway, I'm thinking about Sansui QRX. They have excellent vario-matrix decoder/synthesizer, but they don't have pre-outs. Perhaps a good speaker level to line level converter would be a good thing in this scenario.

I turned down the bass on the Sanyo quad and it seemed to help. I'll continue to adjust if necessary.

I've had a couple of Sansui quads... the best one being the QRX5500. I found out later that the best vario-matrix appeared in later Sansui quads... maybe starting with the 7000 on up. But don't quote me on that. You could post that question in the General forum... I'm sure someone would be able to tell you which units have the TOTL vario-matrix.

I A/B'd my Sanyo quad with the QRX5500... to my amazement, the Sanyo had better separation all around... L to R and Front to Back. I couldn't believe it and tried to talk myself out of the Sanyo, but the difference was so great that I ended up selling the 5500. I would have loved to have kept it... the most beautiful receiver I've ever had... and quite the beast.

As for line level converters, that one from Crutchfield looks to be the best/most stout. But they want $40 for it.
 
Thousands and thousands of years ago (1975--1985, or around that time, anyway) both Carver and Soundcraftsmen sold impedance-matching devices for expressly that purpose--connecting the speaker output of some mass-market crap receiver to one of their wonderful, powerful amplifiers. I kinda remember that Carver and Soundcraftsmen got about thirty dollars for 'em; but I bet there were a lot "thrown in" with the purchase of the amplifier.

The Carver was a "Z-1 Wideband Z-coupler".
https://www.ebay.com/itm/CARVER-Z-1...m570.l1313.TR1.TRC0.A0.H0.XCarver+Z.TRS0.TSS0

https://www.ebay.com/itm/CARVER-Z-1...m=R40&rt=nc&_trksid=m570.l1313&LH_TitleDesc=0

The Soundcraftsman unit, I can't find a model number or photo. It was similar to the Carver unit.

I don't have schematics, but I always suspected they were a small transformer inside a presentable box, with wires and jacks as required for hook-up.
 
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