Hybrid vs. Straight Tubes

It's Monday! and I was back at work after 3 weeks off. But the good news is... I did bring a sound level meter home (TES 1350A).

I measured the level in my sweet-spot at the volume levels described below. Each level was measured while listening to various pieces of music (Take 5 Dave Brubeck, and Pergolesi's Stabat Mater - "Quando corpus morietur"). The distance from the speaker to the sweet spot is 3m.

1 - Normal Listening (WAF 10)-> 55 to 65 peak to 70 dB
2 - My Optimal (WAF 6) -> 70 to 82 peaks to 86 dB
3 - Loudest setting "Nick Turn the music down!" (WAF 0) -> 80 to 88 peak at 96

I then took more measurements for the first two settings playing a 1kHz tone and measuring the level at 1m.

Level 1 - 75 dB
Level 2 - 90 dB

So to conclude, Tvad if I understand you correctly with 1wpc I would have just enough power to listen at my optimal level. But since I do not want to be driving my amp at full power constantly a 10wpc would be preferable. 30wpc would provide more power than required.

But the above conclusion is strictly considering the rated wattage and not the dynamic power (point raised by Pubul57). Is there anyway to determine an amps dynamic power from it's specs?

Mechans' comment re: "tube output stage is critical, period" is probably fair enough, overall. In the case of the RS6, it's even more applicable. Speakers which have a spike in impedence in the presence range (IIRC, the RS6 qualifies - as does the Merlin VSM, another speaker that "flatters" tube output stages) sound more dynamic and alive with the right tubed ouput stage. You might get a taste with tubed drivers and SS output, but you won't get the whole deal.

Good Luck.

Marty

I'll add that I had 3 different tubed preamps in front of my SS amps over the time I owned them, none of the combinations have come close to the character of the tube amp/passive pre combo I'm running now. The magic IME lies in tubed amplification.

Have owned SS up until just a few days ago, when I had and took the opportunity to trade my Nuforce class D 160w mono's for a Cary Rocket 88R (30w triode/60 ultralinear). Despite the low power rating I notice no degradation in sound quality, even at fairly loud levels running in triode. I was afraid that my Usher 87db/8 ohm (dipping into 4 ohms) speakers wouldn't be a good match for tubes. The Cary is happily putting that notion to bed. Quite happy with the sound.

Wattage still does relate to loudness, but you also get the same loudness with less power if you have more efficient speakers. The other issues is how an amp handles clipping (tubes do it well, SS not so good), and short dynamic output for handling transients - and you can't really tell that from wattage. Some 50 watt amps have tremendous dynamic power that is only needed for very short periods of time and can sound every bit as "loud" and a 200 watt amp that doesn't handle transient power delivery quite as well. I can tell you a Pass XA30.5 sounds like a lot more power than many other "30 watt" amps.

In regards to this issue of power.

Today I audtioned a really nice Leben CS600 amp (32 watts). Unfortunatlely price wise it is more than I can afford right now. The dealer had as an alternative CS200 with only 10 watts of power. He claimed that it should suffice for my RS6s...

I don't get it! I used to think that wattage was directly related to volume. I know now that this isn't the case, but what does wattage provide (this seem like a very obvious questions)? How can I know that a given amp will be suitable for speakers?

my favorite tube integrated amp is an original jadis orchestra. i believe the first version was 60 watts.

listen to this product and decide for yourself if it has the qualities of tube amplification which satisfy your taste.

I think you should buy as much power as you need (which may be less than you think). Which is dependent on speaker, room, and loudness requirements. In almost every case I have experienced, lower powered amplification sounds better to me, IF, it is enough power to reach the volume level and dynamic you are looking for. I find you need a lot less power with tubes, because they simply sound much better at handling peak power demands without distortion. At the stereophile show a few years back, there was a side by side comparison between a 30 watt tube amp and a 200 watt SS amp - guess which sounded louder without distortion.

I think Tvad's responses are dead nuts on;I also have heard changes by rolling tubes in a moscode 401HR friends system;I think George even encourages rolling in his products as well.
As for the power issue I would buy the most power you can afford within reason;probally other users will slam me on this but it has always been in my case a positive.

I've had ss,moved to all tube power and am now quite satisfied with a tube/ss hybrid amp designed and built by Space-Tech-Labs in Vancouver.It provides me with the best of both technologies,and pairs well with my stats.

Tvad,

I am on leave from work, I will be back next monday. I will borrow the decibel meter we have for measuring the sound level of machinery in industrial environments.

I will post a response then.

Cheers.

First and foremost, thank you all for the feedback.

I am currently using a Marantz integrated amp with 40w RMS and I have no real complaints about power.

However, in response to Tvad's comment "provided the room is small to medium", I live in an open concept condo, the room were my system is installed is 24' x 24' with 12' ceilings. My listening area takes up about a 1/4 of the space (A photo can be seen on my virtual system). Could this be considered medium?

As mentioned above I don't have in issue per se with the power of my current set up but I was under the impression that to get the most out of your speakers it is preferable to drive them and the top end of power range (120W for RS6).

I have been looking at the Prima-Luna & Rogue amps. But I recently had an opportunity to purchase a Jolida 1501RC for a very good price. I think I'll forgoe the offer and wait to find the recommended amps at a good price. I am also considering the Mystere amps, designed by the same people as Prima-Luna.

One last point regarding the Jolida. When I auditoned my speakers, I tried them with a Jolida 302b in addition to the Marantz PM8003 (70W RMS). The tube amp sounded much better. But I did not have any other tube amps to compare it to.

Thanks again.

I've heard the Jolida hybrid amps and have not been impressed. That said, I guess I haven't been overly impressed with the Jolida 302b I had years ago. Overall, I'd probably go for a tube integrated, perhaps something other than Jolida.

TVAD writes:

"However, I heard a significant change in the Moscode 401HR hybrid amplifier by changing non-output, nine-pin tubes."

The same can be said for changing the input tubes in tube amps as well. Changing cables will change the sound too, so I'm not really sure what the point of that statement is.

But I do know that I used to use tube/MOSFET hybrid amps and now I'm back to all tube designs. This is not to say that I'm not open to trying other designs in the future.

If yoo really want to find out why tubes have a very dedicate bunch of fanatics. To hear what makes a tube amp really magical, it is imperative that you have an all tube power output stage . Not a shadow of doubt period about it.

The really expensive part of a tube amp is the output stage, if you use tubes in driver stage and mosfet output stage you can get a lot of the tube sound. I used an amp like this at one time and it worked well.

You will not hear real tube sound from a hybrid.This is my opinion,others will probably disagree and that's fine by me.

I think the real 'sound' of tubes is found in the amp output not in a couple of tube drivers in front of a SS output. I also think that the difference between a 40wt tube amp and a 100 wt ss amp is relatively nominal. Don't forget that this difference amounts to something like 4dbs, not much. So if an all tube integrated floats your boat go for it.

BTW, FWIW, a few years ago I bought a Primaluna One which has a passive line stage and uses EL34's. I liked its tone (color if you will) but it was relatively slow and thick so I wrote it off to the attic. Not long ago I got it out and tried connecting it to a tubed pre-amp using one of its regular inputs and using its VC to control the gain from the pre-amp (much the same as you would with a lot of amps which have gain controls). I was amazed! The tone was similar but the speed and resolution was greatly improved. So, something for consideration, were I to buy another integrated would be whether or not the gain stage in the integrated were active or passive. In most integrateds (including the two that I have) it is passive and clearly now I would opt for having an active pre-amp section.

Your speakers are efficient enough why not just go tubes with a nice Int Amp like the Jolida, Primaluna, Rogue, etc.

I was in a similar situation wanted to replace an old SS receiver and said shy not bought a used Primaluna PL2 since it takes a nice variety of power tubes from EL34 to KT88.

Got the tube bug and added a tubes phono stage and tuner. Really enjoy that rich thick sound.