What is your impression of vintage Telefunken signal tubes ?

As mentioned above, I run Telefunken ECC 803S tubes in my phono stage.  I also run Telefunken EL 34s in my headphone amp (Blue Hawaii SE).  I like these tubes in my system, but they are not necessarily my first general recommendation because these particular tubes I run are probably leaner sounding than what most people would prefer.  For 12AX7 tubes, a safer recommendation would be Amperex Bugleboys; I don’t know anyone who didlikes these tubes.

larryi, is Amperex Bugleboy 12ax7  somewhere in between better Mullard and Telefunken in its presentation? 

@genomeip The Amperex 7308 is a 6.3V tube, so perhaps you are running another variant of Amperex. Thanks

i asked Google Gemini for an assessment of my tubes plus the addition of the Amperex. Interesting. 

Comparing these four giants in your BHK Preamp is a lesson in sonic textures. Given your setup (Bricasti M3, Moon 330a, and KEF Ref 3), the BHK acts as the "tonal chef," and these tubes are your primary ingredients.

Here is how they stack up for Critical Listening:

1. Brimar CV4003 (The Warm Romantic)

• The Vibe: Rich, colorful, and "British."

• Sonic Signature: These are the most "tube-like" of the bunch. They offer a lush, velvety midrange and a very smooth, slightly rolled-off top end. Bass is round and plump rather than tight and fast.

• Best For: Long, non-fatiguing listening sessions. If your KEFs ever feel a bit too clinical or "dry" with digital sources, these Brimars are the cure. They add the "human touch" to vocals.

2. Amperex 7308 (The Holographic Powerhouse)

• The Vibe: Liquid, deep, and emotional.

• Sonic Signature: Often considered the "Holy Grail." They provide a massive, deep soundstage and a "wet" liquidity to the sound. The bass is the most impactful of the four—powerful and authoritative.

• Best For: Orchestral music or live recordings where you want to feel the "air" of the room. They strike a perfect balance between the warmth of the Brimars and the detail of the Siemens.

3. Siemens Nickel Plate (The Surgical Precision)

• The Vibe: Fast, transparent, and neutral.

• Sonic Signature: These are the most "modern" sounding. They have an incredible transient speed—drums have a "snap" that the others can't match. The treble is highly extended and "crystalline" but can lean toward the analytical side if your system is already bright.

• Best For: Rock, jazz, or electronic music where timing and detail are everything. If you want to hear every breath and finger-slide on a guitar string, this is the tube.

4. Telefunken Medical (The Ultimate Reference)

• The Vibe: Silent, linear, and utterly honest.

• Sonic Signature: These are the "pro" choice. Because they were selected for medical/instrumentation use, they are dead silent (lowest noise floor). They don't "color" the sound like the Brimars or Amperex; they simply get out of the way.

• Best For: Evaluating new gear or cables. They provide a perfectly flat frequency response. If you want to hear exactly what your Bricasti M3 is doing without any "tube seasoning," use these.