To Almarg and others, I missed your e-mails about the NuPrime ST-10 amp and actually responded, but it was not posted. Something must be screwed up with AG's thread and posting system
To Almarg, I got an a definite answer from Rogue HQ today about the Sphinx integrated variable output line, they call a "pre-out". If I connect a separate power amp to line 3 which is a variable output, the amp must have a input impedance of 10,000 ohms or more. The reason is this: the front panel function DO NOT go through the two tubed output stage of the Sphinx pre-amp, but through a special op-amp that allows the use of the volume and balance control, and also the phono input and CD input. The phono has it own line marked phono, so lines 1 and 2 are available for a CD player or tuner which I have
I was also informed by the Rogue tech that the sound may not be quite as good through the op-amp device,, but he also claimed the op-amp is a very good device. I am not sure what that means because I know nothing about op-amps, their function, or their quality rating. However it is worth taking a shot at it whatever amp I decide. The Odyssey Stratos Plus is high on the list..
However, if the sound is equal to what I have, or only marginally better, or worse, inferior to what I have, I will then hunt for a new pre-amp. BTW, about a year ago, I replaced the two stock tubes in the Sphinx output stage with Mullard CV4003 tubes. This was based on the recommendation by a member who also had a Rogue Sphinx. The purpose was reduce some of the edge and bright tinge that is part of the sound because of Hypex Class D amp. It worked, but did not reduce all of the edginess or glare.
Al, or others, your thoughts and comments on the op-amp use in the Rogue Sphinx will be appreciated.
Also, a member has a BAT VK-250 SS amp for sale. He mentioned also that he used it with BAT VK-31 pre-amp, and it was the best combo to date, even though he replaced both with ARC Reference separates Both were issued in 2006 when he bought them, and he kept them for 10 years. The review on VK-250 in TAS in Nov. 2008 was politely neutral about its sound quality; I did not find any other reviews so far. I will be googling up reviews on BAT VK-31 pre-amp soon I don't know depending the pre-amp feature if the combo is worth the money, and he is going to have to come up with a very sharp quote far under $3000. to get me motivated. Thanks again, Jim .