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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.

arhgef
mahgister's avatar
mahgister
12,734 posts
 

Exactly my experience too...

Thanks..

So my experience is that inserting a good tube preamp into the amplification chain depends on the quality of the rest of the gain stages in the chain. For example, the Jade easily beats small s-state amps in  active speakers, from my testing so far (low to mid price). But if the other gain stages are in fact of comparable or higher quality than the Jade, the effect can be zero, or reversed

ghdprentice
6,423 posts
 

I have a headphone amp that is powerful enough to be a headphone amp or an integrated amp and power speakers. The Woo WA5.

pindac's avatar
pindac
2,443 posts
 

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.

mbmi's avatar
mbmi
446 posts
 

The 4K , Audio-GD HE1 XLR....10 tubes, it’s own Regenerative Power supply. Sings with Any Amp I put it with... Simply a fantastic sounding PRE !     Caution:  It's a Monster.

thermionicemission
16 posts
 

@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.

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