Phantom Load

[Menticol]

Hello!!

As I posted before, my room sound system consist in:

LG DWE 630 DWE 2.1 home theater to drive front speakers
Car stereo for rear speakers

Others: car EQ, etc.

Nothing big or expensive, but works nice.

The topic is, I got a tube amp, and put it on place of the LG. But I really missed the LG bass, so I started using it with the speakers removed (just the sub-woofer alone).To avoid ruining the amp, I put a 5W 6.8 ohm resistor as phantom load on each speaker output.

The removed speakers are 8 ohm rated. I used 6.8 ohm resistors just because I had them on stock.

Is a good phantom load, or I'm ruining it?

 

[Nigel Goodwin]

A transistor amp should be pefectly safe with no load at all, adding a load lower than it's rated impedance is much more likely to cause a problem.

Seems a bizzare thing to do adding a valve amp though?.

 

[Menticol]

Just on time Nigel, thank you! Resistors removed

Well, I'm just experimenting. All people says Tube amps sounds better, bla bla bla. I know that depends of what equipment do you have, speakers, your room configuration and materials, etc... and my equipment is not exactly the best

But even against all the odds, why not giving a chance to my old radio? It's aaa... it says Mercury Stereophonic, but I cannot find any entry for that brand. Circa 1962, as a hand writing says in the back. Some parts are Torotor. I'm using the PHONO IN mode

Audio Tubes are:

EL-84
ECC83

The full wave rectifier is a EZ81, but I guess that is irrelevant.

PS: I'm having a veeery ugly interference here! Severe ground loop
PS2: Treble response is much much better, but bass is poor

 

[Menticol]

I've connected all the grounds together, and ground loop dissappeared. Tube's treble is clear as crystal, bass is poor, but the other amps compensate it.

But in exchange, all noises from the computer (even hard disk spinning) are beign picked up by the tube amp! What a mess!

EDIT: No, shielded wire doesn't fix it. Maybe I need an isolation transformer or other way of coupling?

 

[Hero999]

Why are you using a vlave amplifier?

The LG probably sounds much better anyway.

 

[flat5]

Don't use the phono input. Use a tuner (line) input.
Do use shielded cable.

I'm a people and I don't say tube amps sound better - mostly guitar people would say that
and what do THEY know.

 

[Nigel Goodwin]

Well, I'm just experimenting. All people says Tube amps sounds better, bla bla bla.

No, most people say that valve amps are much poorer, high distortion, high noise, and poor frequency response.

Many of us here come from the valve amp days, and wouldn't consider going back to the bad old days.

 

[Menticol]

Don't use the phono input. Use a tuner (line) input.
Do use shielded cable.

I'm a people and I don't say tube amps sound better - mostly guitar people would say that
and what do THEY know.

Ok, maybe I've generalized a bit I'm unable to get the tuner. Maybe it can be done, but that radio doesn't have PCB, instead point to point connections and wiring. I'll attach a picture, very hard to troubleshoot!

No, most people say that valve amps are much poorer, high distortion, high noise, and poor frequency response.

Many of us here come from the valve amp days, and wouldn't consider going back to the bad old days.

I don't wanna contradict your experience guys. I just remember some serious people (at least they call themselves "serious" ) saying that tube sound is warmer. Warmer? I don't know what warmer is, strange audiophile vocabulary*

The only thing I'm sure, is that the high frecuency sound is more accurate, with the LG it seemed muffled, like puting a dirty sock on the tweeter. Now I feel like having the drummer's cymbals next to me. Maybe the tube amp compensated the LG bad high frecuency response.

The bass response is very crappy, as you said, totally right

* About "warm" things and vocabulary, I have a question:

When using a bad quality sub-woofer to hear someone playing a bass guitar, you don't hear notes, instead you feel it like hitting your stomach. BUM! BUM! BUM!

But using good quality woofers, I mean, mid range speakers, the bass sounds more accurate. I'm not saying the mid range is the same as a sub-woofer, but somehow the midrange can go lower and reproduce the low frecuencies, in a very pleasant way.

I think that's related with the crossover point and another things, but that's offtopic. Question: Is that the "warm" sound everyone talks about?

 

[Nigel Goodwin]

I don't wanna contradict your experience guys. I just remember some serious people (at least they call themselves "serious" ) saying that tube sound is warmer. Warmer? I don't know what warmer is, strange audiophile vocabulary*

'Warmer' means highly distorted, and with poor frequency response, as you say it's a very strange thing to be wanting.

 

[Menticol]

Thank you Nigel! I'll not call the good bass as "warm" bass never again!