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.
As you are adding Build Your Own Amp's into the discussion, I feel you should be made aware of the Pass Designed Korg B1 Pre-Amp'. I have referenced its usage on quite a few occasions within this forum. This is not a Phono Pre Amp, but personal experience of it in use with a Vinyl Source on a variety of systems has shown the Sources in use to have a presentation that has exceptional attraction. |
@arhgef Having the same MC462 as you do, I will share some experiences. At first I was using a Fisher 400 CX-2 that I rebuilt. A wonderful sounding unit and possibly the best vintage preamplifier of all time. This combo created a nice vintage / tube undertone to my system. The upgrade bug bit and after visiting the McIntosh factory, I stopped by Audio Classics in Vestal, NY and made a great deal on a new C22 MKIV and had it shipped to me in Florida. What a great combo! Some tube warmth, but a much more of a modern hi-fi sound. Unable to leave well enough alone, I wanted to see if the C22 would respond to some tube rolling. Much to my surprise, I could hear subtle differences with every change I made. I finally settled on a Telefunken ECC801S for the output, a Telefunken ECC83 for the input, and Amperex 7025’s for the phono. The preamp was completely transformed and I have found my audio nirvana. I recently ordered a Moreplay preamp kit from Bottlehead to build for a second system and hope to have the same positive experience you did. |
Thanks to all. Lots of good advice here. Further research and your posts confirm that a single ended pre in the chain certainly can make a positive difference. I like comparing vintage speakers and currently am using a B and W 803 matrix 2. The “sharpness” of that speaker maybe makes the tube a good choice. Will try to DIY a simple pre so that I can compare the effects of different tubes etc, and I think some of the reason a SET tube pre sounds good is the simplicity of the circuit, so this should be doable. A new adventure… Thanks and enjoy your music and systems. |
