surprising comparison of tube preamps

Hi and thanks for your help. I have been using an ARC LS25 II preamp going into a Mcintosh Mc462 amp. One source is a turntable going into a Parasound JC3+ phono pre. When the ARC broke, I tried a Bottlehead Crack headphone amp as a preamp. I was very surprised to see how beautifully this worked. Really rich sound. Maybe it was less accurate (could not do a direct comparison with the LS25), but it was certainly great to listen to, for my taste. I looked into this some and wondered if the lush sound came from the fact that the Bottlehead was using a simple SET OTL circuit, compared to the hybrid circuit in the LS 25. Still you would think that the ARC unit, costing so much more, would sound better.  I am wondering if people have an explanation for this but, more importantly, have been looking into getting a very simple tube pre to use for the phono part of the system. Mapletree audio sells a simple preamp that I believe is a SET OTL (are all preamps OTL?). Al  Freundorfer, the designer and owner, kindly agreed to make me a modified version to test. Some circuits, including a buffer he sells, have the ability to adjust the 'warmth' and extent of tube sound - he would build this into his amp for me (it is available on some of his other products). Is this a good idea? Could I reproduce the effect I heard with the Bottlehead? Not sure how those 'warmth adjusters' work. Thanks a lot for your help.


@atmasphere I'm reading with keen interest and hoping to learn.  So is your point leading to any reason to believe that integrated units have an  advantage?  Any, or would they need to be fully balanced from input to output?  I'll just sit back and learn now.   

@arhgef - I am not suprised at all. I have an OTL headphone amp that I also use as preamp in my office system. Between the DAC and the integrated amp to the speakers. Although one more gain stage is not ideal, the results are clear: The more of the total gain made by the OTL, the better the sound. It might even improve the sound in my main rig, but is not practical to use there (maybe, I should give it a try). I also agree that AR can be a bit lean and analytical, I have other tube gear with more bloom and warmth, which I like (to an extent). I think the great thing about OTL is relative simplicity. So I am sceptical about 'simulations' (but have not heard your example).

Great advice in this thread on several fronts.  Take some time to settle into the new sound.  Sometimes different sounds better at first but given time, you might start to notice you aren’t as in love with the new sound as you thought.  Synergy in your system is key, if your Mac is designed to operate best with balanced inputs, that will play a role in how well a pre integrated with your amp.  Simplicity, synergy and thoughtful design often win over price, great advice that you don’t need to brake the bank to get a sound you love from your system if you know what you like and are thoughtful about the components you buy. 

good luck!

This is exactly the question I've been researching. I put a $400 Schiit Valhalla 2 tube headphone amp in place of my SS preamp. It sounded good from the start but really opened up when I configured it differently. I run the Valhalla with no attenuation, bought a Schiit Kara, and use it in passive mode as a volume control. 

Now I'm looking at upgrading that config with an LTA Velo headphone amp/preamp. I'm also looking at some others. But I agree that the simplicity of the design is key.

The Rogue Audio RH-5 head phone amp is highly regarded. Used by many as a line stage pre. Occasionally they pop up on the used market.