2. amps-preamps
  3. 1126736041

Attention Sonic Frontiers owners.....

Hi, I have recently been corrected of a mistake regarding the Sonic Frontiers Line series pre/amps and Power Series of amps. I was always informed that the most important tube spots for these products was the rear most LV1, V1 rear positions. After trying a little experiment with my tube amp I became curious about a tube swap that I performed. I emailed SFI and I was then told of the circuit topology. It is broken down like this for the Line 2 and Power 2:
Line 2:
V1 and LV1 – Input buffer
V2 and LV2 – Gain stage
V3 and LV3 – Cathode follower
Power 2:
V1 and LV1 – input buffer
V2 and LV2 – voltage amplifier
V3 and LV3 – driver
V4 and LV4 – cathode follower.
I’ve since started using the gain stage slots for my better tubes and have been pleasantly surprised. I recommend that you try the same if you own one of these products. I'm not sure about the Line1+3 or the other power series of amps but I recommend you email SFI about them for more details.
Greg
gsselling

Showing 2 responses by gsselling

gsselling OP
29 posts
 
Hi Jim, I am well aware of Chris Johnson and TPC as I have owned SFI gear for 6+ years. I will Email him about the actual job of each of the various pairs. But if you are right and the rear slots are the most important then you are saying the Buffer stage is more important then the gain stage. I hear differences in the slot movements but im trying to maximize the importance of a single pair of tubes in each piece as I don't wish to spend that kind of money on NOS. I find the sound right now using the gain slots for my better tubes to be much more dimensional sounding. I am using EH 6922's in the 2 pairs and in the gain slots a pair of Siemens 7308/E188cc's gold pins in the other slots. I have a host of other tubes that ill be playing with in due time but right now I am enjoying this setup.
Greg
gsselling OP
29 posts
 
Hi Jim, wow, you've really dug into this with all of your might!!! This past week I took out my Siemens E188cc's from my amp and have been running both pairs in the LV1+2 and V 1+2 slots of the pre amp. I have found that they are much better paired like this while running all EH 6922's in the Power 2. I have ordered some more pairs of them to give them a shot in the amp to see what kind of results that would bring. Yesterday I finally got around to doing some room treatments in the way of Auralex absorption panels and some of their bass traps and the improvements that has brought is astounding. I will post more on all of this at a later time and I'll put up some pictures on system here.
Regards
Greg
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