Using a solid state pre-amp as a replacement front end to tube integrated

[FauxHall]

I've got a pretty decent, new Wilsenton R8 integrated amp made in China. I run either KT88s or KT90s in the power tubes. However, the only controls are line input selection, triode/UL, and volume.

I'm thinking of getting a fancier, vintage pre-amp to bypass the front end on the integrated and just use the Wilsenton for the power amp section. However, that would bypass a single 6SL7 tube per channel but I would gain tone controls, loudness, and other switches and gizmos. I might lose the Wilsenton's remote control though.

I'm loving a nice wood cabinet for the pre-amp of the likes of a Luxman or a Marantz. A Marantz would only be SS while a Luxman could be either -- CL-350 maybe for SS or CL-38u for tubes, Of course there are plenty of other nice preamps out there, like ARC or Counterpoint.

I'm thinking a SS unit would have a better SNR than a tube pre-amp and are cheaper in general.

Opinions? Experiences?

 

[swechsler]

I'm not familiar with that amp, but it doesn't appear to have separate power amp inputs. How do you plan to only use the power amp section without those?

 

[FauxHall]

 

[swechsler]

OK, good, I couldn't find a closeup picture of the rear panel.

 

[rothwellaudio]

...but I would gain tone controls, loudness, and other switches and gizmos.

Opinions?

Personally, those are things I live happily without.

 

[Bodyblue]

I have a recapped Marantz Model 33 that I use with a Sony 330ES amp and I am totally in love with. The preamp section of the Marantz 1060 is also renowned as one of the best. Recapped and at factory specs either one is very difficult to beat. I have both and I prefer the 33 by a hair. I also have a Marantz 3200 that sounds damn nice......

 

[eiraved]

I'm thinking a SS unit would have a better SNR than a tube pre-amp and are cheaper in general.
Opinions? Experiences?

AK members had a SoCal get-together where I brought a McIntosh C32 preamp (SS), a well regarded preamp. We hooked it up to a tube amplifier (can't remember the make) and it was not a match made in heaven, just did not sound right. Not to say all SS amps will sound bad, but it was not good in this experience.

 

[sqlsavior]

I get that you're after more control, but to do what, soundwise? There may be a better way to do it...

 

[FauxHall]

There's a Schiit tone and balance control (Loki) that might work but I have two line level inputs (a Sony HiRes player and a phono amp) so would need two of them.

I do find utility in a loudness treatment as it has worked for me before in adjusting the spectrum versus volume to match human hearing.

With the Klipsch Forte III's 12 inch woofers, some recordings get a bit boomy in the bass in my music room. Some are too strident in the treble with the horn tweeters. 95% of recordings are fine but a little tweaking would be useful.

Plus, I crave a wooden cabinet in a nice veneer. Call me superficial if you want, but an attractive home deserves fine sounding equipment with a fine appearance.

 

[Legrace]

A SS integrated combined with tubes and both in turn applied towards biamping nice speakers like yours can deliver impressive results.

 

[sqlsavior]

With the Klipsch Forte III's 12 inch woofers, some recordings get a bit boomy in the bass in my music room. Some are too strident in the treble with the horn tweeters. 95% of recordings are fine but a little tweaking would be useful.

Do you run in triode mode, or ultralinear?

With my PrimaLuna Dialogue Premium, with KT-120s installed, ultralinear was superficially more attractive because it was louder, but triode was so superior sounding (to my sensibilities) that I would sometimes wonder what was wrong, only to find that I had not switched it to triode mode (it comes up in ultralinear).

 

[twiiii]

Try borrowing something before committing monies. The distortion or coloring you may not feel comfortable with may be totally confined in the amp section. In which case no matter what you do the sound will remain colored.

 

[FauxHall]

Do you run in triode mode, or ultralinear?

With my PrimaLuna Dialogue Premium, with KT-120s installed, ultralinear was superficially more attractive because it was louder, but triode was so superior sounding (to my sensibilities) that I would sometimes wonder what was wrong, only to find that I had not switched it to triode mode (it comes up in ultralinear).

Depends on the recording. Big stuff like symphonies or driving rock it's usually UL. Vocals and chamber music tend to sound better in triode.

Try borrowing something before committing monies. The distortion or coloring you may not feel comfortable with may be totally confined in the amp section. In which case no matter what you do the sound will remain colored.

One sonic benefit I'd like to explore is a lower noise floor. The Klipsch Fortes IIIs are very efficient so I can hear a touch of tube noise when there's no music and the volume control is up high, say above 10 or 11 am, although I seldom play music above 10 am. My hypothesis is that adding a quiet SS preamp in place of of the 6SL7 tube front end will reduce that noise level, besides adding tone controls, loudness switch, etc.

In fact, when I look at preamp specifications, I focus on the SNR for line level inputs. The Willsenton is rated at 91 dB overall with the 6SL7 as front end tubes. An Icon line stage pre-amp is rated at 90 dB and uses 6SN7 tubes only. That supports my guess that the low signal tubes are the constraint on SNR in my tube integrated amp.

Making comparisons difficult is that there are two ways to state the SNR. One is "naked" while the other way is per IHF-A weighing. The latter is usually higher but its not always clear which is which.

A modern SS preamp like a Parasound Z3 is claimed good for 100 dB. A new Luxman SS C-1000 is rated at 120 dB while a new Luxman tube preamp CL-38uC is >100 dB. A vintage Sony TA-E86 is >105 dB and a Sansui C-2301 is 110 dB..

What this tells me is that a good SS preamp driving my tube power amp section will be quieter than the tube integrated amp alone.

Seems like the current craze to build and sell hybrid integrateds with a tube front end and a SS power amp has it backwards - if SNR is your criterion. Of course, its cheaper than the other way around!

Amirite?

 

[j!m]

I’ll make a suggestion for a Perreaux preamp. Very clean, so it won’t “add” to the tube sound of the amplifier.

I am very pleased with the pairing with the counterpoints. Those are hybrid, but I think illustrate well.

 

[rothwellaudio]

View attachment 1873926

One sonic benefit I'd like to explore is a lower noise floor. The Klipsch Fortes IIIs are very efficient so I can hear a touch of tube noise when there's no music and the volume control is up high, say above 10 or 11 am, although I seldom play music above 10 am. My hypothesis is that adding a quiet SS preamp in place of of the 6SL7 tube front end will reduce that noise level, besides adding tone controls, loudness switch, etc.

Are you sure that using the pre-in bypasses any of the valves? It's possible the the auxilliary inputs go through a volume control and the pre-in just bypasses the volume control and nothing else. If that's the case, there won't be any drop in the noise floor.

 

[FauxHall]

Are you sure that using the pre-in bypasses any of the valves? It's possible the the auxilliary inputs go through a volume control and the pre-in just bypasses the volume control and nothing else. If that's the case, there won't be any drop in the noise floor.

I have an incomplete schematic which lacks that detail but the website says this:

• With pure post-level function, it can be connected to independent preamplifier signal input.​

Also, see the photo I posted near the top of the thread. All in all, I'm willing to take my chances that the "pre in" connection goes right to the driver tubes.

I will note that the McIntosh C32 preamp mentioned by "Eiravid" about has a 20 dB gain which seems high - most I've seen are about 14 dB or so.

I also see that there is a Counterpoint Solid 8 preamp offered in Greece that's 220VAC - close enough to my 240VAC. Always admired Counterpoint gear.

 

[rothwellaudio]

I have an incomplete schematic which lacks that detail but the website says this:

• With pure post-level function, it can be connected to independent preamplifier signal input.​

​

That suggests to me that the pre-in just bypasses the volume control. If you could post the incomplete schematic it might give us a better idea.

 

[sqlsavior]

I'd suggest either checking out "The Truth" preamp, or getting a TVC. Either should get you increased clarity and lower noise. Neither will provide tone controls.

And rothwellaudio has a good point. You may only be bypassing a pot.

 

[Lavane]

If your tube amp has a volume control, it most likely doesn't have a preamp per say. Add a volume control to an amplifier and it becomes an integrated amp. My main tube power amp has a volume control. Using a preamp, I just run the volume control on the amp wide open. At full volume it's the same as not having a volume control at all. I've used solid state preamps with tube amps with good results. I've used the volume control on my tube amp to tame the high output of some CD players. If you aren't getting enough usable range with the volume control on the preamp, just turn the amp volume down some. The only source I have problems with are CD players having a high output.

 

[FauxHall]

Given the question raised about what the back panel means specificically by "Pre In", I sent an email off the "China HiFi where I bought the unit:

"With my high sensitive speakers (Klipsch Fore IIIs), I'm noticing some static at high volume with no signal input.
I'm thinking of using a separate solid state pre-amp feeding the "pre in" connection. Does this connection bypass the R8's volume control AND the first tube stage (6SL7s)? If so, that could both reduce the noise and offer tone controls, etc.

"The schematic you sent me lacks this detail.

"Thank you."​

We'll see what they say.

UPDATE: the guy at China HiFi said:

"Yes, if you set it at "pre-in" , the pre-amp of Willsenton will not work."​

Assuming he understood my question, I think that's definitive enough for me.