Tube headphone amp as pre amp to solid state?

You would get a bit different sound presentation. I would use the tape loop on the NAD in your case to hook up with the Little Dot models that have pre-amps outputs.

Edited by john57 - 9/10/11 at 6:28pm

Hi Nicholars and John57,

 

I have used my Little Dot MkIII now for over a year as a preamp for my Outlaw RR2150 receiver utilizing the external loop.

 

After extensive experimentation with driver tubes I must say that the results are spectacular - I could not be more pleased. Basically I have the 100W power of solid state with the wonderful tube sound. (Think grape juice compared to fine wine!) Another plus is that my receiver has tone controls so that I can adjust the tube sound to a much greater degree than running headphones straight from the LD MkIII.

 

The biggest difference compared to headphones is the sound stage - R to L, front to back, and sometimes, in a very good recording, height top to bottom. The cans that I have seem to be more constricted in sound stage. In addition, the sound is different through the speakers, even though good tubes for the cans usually translate into good tubes for the speakers. Personally, I much prefer the speakers to the cans, and with the great speakers I have I sometimes feel that they have even more detail than my Audio Technica ATH-AD700 headphones.

 

As John57 points out, the Raytheon 5654/6AK5 small mica tubes are among the top on the list, together with Mullard M8100/CV4010, Tung Sol 6AK5 and Amperex PQ 5654. (The Voskhod tubes that a lot of people like don't work for me.)

 

For speakers I am using a double set-up of Polk Monitor50 speakers with PSW10 sub woofers (four speakers and two subs). These speakers can be bought from Newegg for $80 each on sale. Could not resist a second set at these prices - the sound is more full bodied and expansive. These speakers beat my old audiophile $3000 speakers hands down!

 

I use a receiver which is a solid state preamp-amp combination. It has facilities for an external loop, and I connect the Little Dot there. With the push of a button I can switch between the receiver alone with it's built in preamp, or add the tube preamp, and the difference in sound is very noticeable. I really feel that I get tube sound with the 100W power of a ss amp. The colder and more dull ss sound is gone, the bass has much more definition, and the entire presentation is much more lively and involving.

I should add that I get the best sound (read best bass) when I crank up the volume to 80% (short of clipping) on the Little Dot, something that would blow out my eardrums with my headphones where 20% volume is more than enough. I regulate the volume with the volume control of the receiver.

 

 

 

http://www.outlawaudio.com/products/rr2150.html

 

Not sure if this applies, butnI used a RSA Stealth pre with a solid state amp and it was the best mynsystem every sounded.

Not all tube based headphone amps  have pre-amp outputs but many of the Little Dot all tube models have it. Yes, generally tubes can give a smoother,warmer and  less edgy sound. It does depends on the make and type of tubes used.

Two things:

1. You need a headphone amp with a preamp out function.

2. You need a receiver where it is possible to bypass its internal preamp.

Running a preamp into a preamp is a problem. You can overload the second preamp and make it distort or worse.

In your situation, I'd sell the receiver and buy an amp with preamp out. Then I'd buy a standalone power amp and power that.

Personally, I run a dedicated preamp with two tape loops. I can connect a headphone amp to each tape loop, a power amp and four separate sources. I can send any source to either headphone amp or to the speakers.

Also, maybe reconsider the Little Dot. Get a Bottlehead kit instead. Higher quality and more reliable.

Hi Uncle Erik,

 

Thanks for your post. I have used the Little Dot MkIII in an external loop to my receiver for over a year, and I have not come across any distortion unless I turned up the Little Dot full tilt, which I attribute to clipping in the LD amp. The LD has preamp out RCA connectors.

My receiver has U shaped jumpers between preamp out and main in, but it seems that I cannot switch off the preamp; however, I could apparently add another amp instead, bypassing the built in amp.

I spent a lot of time tube rolling and I have found combinations of driver/power tubes that I am very happy with. I have never heard of Bottlekit before, and I am not sure if you have to build them yourself or if they are ready made. I'm not ready to build anything myself, though.

Curious to know what you mean with reliability of Little Dot. The only problem I have had is a Russian power tube go bad on me. I haven't really seen any reports of people having trouble with them.

What kind of preamp do you have that has such flexibility?

I checked the manual for your  NAD 315BEE  and it does not really have a true tape monitor loop jacks or sometimes called a external processor loop either. I have no issue with two of my Little Dot amps. One of my Little Dot amps is also connected to my Active Tannoy Monitors with no issue.