Tube Buffer Recommendations?

[triode17]

Keep in mind the fact that you can't properly drive a SS amp. with a tube pre. The tube pre. outputs are too high an impedance and you will lose Bass. BUT, if you added a tube buffer in between, then all is fine. I say buy a buffer first, then slowly convert to all tubes. I built an Aikido tube buffer, cost me about $75 and it works very well. Distortion down below 0.06%! I think a kit is available, if you can solder.

 

[Lavane]

I bought one of these to use as a headphone amp in the bedroom. Put some nice GE tubes in it and it sounds pretty good. It also has RCA outs and will drive my amps as well.

 

[ejman]

Keep in mind the fact that you can't properly drive a SS amp. with a tube pre. The tube pre. outputs are too high an impedance and you will lose Bass. BUT, if you added a tube buffer in between, then all is fine. I say buy a buffer first, then slowly convert to all tubes. I built an Aikido tube buffer, cost me about $75 and it works very well. Distortion down below 0.06%! I think a kit is available, if you can solder.

Not necessarily so, it depends on the output impedance of the preamp vs the input impedance of the power amp. My Mapletree tube preamp has an output impedance of 600 ohms, My Conrad Johnson MF 2300A has an input impedance of 100K ohms - no problem. In general, as long as a you have a ratio of 10-20 you're OK i.e my preamp will probably be OK with an amp that has an input impedance of over 6,000 and certainly over 12,000 to be safe

 

[Poultrygeist]

Keep in mind the fact that you can't properly drive a SS amp. with a tube pre. The tube pre. outputs are too high an impedance and you will lose Bass. BUT, if you added a tube buffer in between, then all is fine. I say buy a buffer first, then slowly convert to all tubes. I built an Aikido tube buffer, cost me about $75 and it works very well. Distortion down below 0.06%! I think a kit is available, if you can solder.

Of course you can use a tube preamp with a SS amp. Where did you get such bad information?

 

[Tom Bombadil]

Both of my tube preamps have output impedances in the mid-600 ohm range. My SS amps input impedances are in the 33K to 40K range. So that gives me a ratio of approximately 50:1 I'm not going to worry about that. I've seen tube preamps measure at 2000 ohms and higher, and SS amps at 10K. So those wouldn't be a good match.

 

[triode17]

Poultrygeist - Let me clarify this a bit. My first tube loading experience was when I was transferring Beatles LP's to CD. I ran the output of my PAS-3x, phono section directly into the CD recorder (Zin=20k Ohms). The phono Zout is about 100k Ohms! Later, I was trying to figure out why the Bass recorded so low, it was mismatching. So I built the Aikido buffer and run that in between, no Bass loss.
Since then I designed and built my own tube preamp BUT, I built the Aikido buffer into the output of the preamp so it can drive anything without loss.
Normally, the voltage bridging method is used whereas, the Zin of the next stage S/B at least 10 times the Zout of the driving stage. Using an Aikido, there's no worry anymore.

 

[Poultrygeist]

Poultrygeist - Let me clarify this a bit. My first tube loading experience was when I was transferring Beatles LP's to CD. I ran the output of my PAS-3x, phono section directly into the CD recorder (Zin=20k Ohms). The phono Zout is about 100k Ohms! Later, I was trying to figure out why the Bass recorded so low, it was mismatching. So I built the Aikido buffer and run that in between, no Bass loss.
Since then I designed and built my own tube preamp BUT, I built the Aikido buffer into the output of the preamp so it can drive anything without loss.
Normally, the voltage bridging method is used whereas, the Zin of the next stage S/B at least 10 times the Zout of the driving stage. Using an Aikido, there's no worry anymore.

Your statement read, "keep in mind the fact that you can't properly drive a SS amp with a tube pre".

It did not work in your case so that's where your generalization comes from.

 

[triode17]

It did not work in your case so that's where your generalization comes from.

No, I did the math. A phono pre with a 0.1u cap on the output, into a CD recorder that's a 20k Ohm load. One over two PI RC=79.6Hz. Not much Bass above that freq. Look at the Dyna PAS-2,3,3x. It has a stated 1 k Ohm output Z but recommends driving a 100k or higher load. Plus, it all depends on the particular topology of the preamp. The Dyna drives directly from the passive Tone EQ parts, no buffer. Yet, my design uses an impedance buffer on the output at 800 Ohms, so it can drive any amp.

You may only have experience with modern tube preamps, I have had experience with mostly vintage ones that had weak output sections.

 

[Audiovet]

Folks,

As has been hinted at regarding bass, one needs to realise that the performance of a circuit depends entirely on the design, not the active elements. As said one cannot generalise down to tubes vs. s.s. Yes, pre-amps of some 40 - 50 years ago will not drive modern s.s. power amplifiers well, because they were never designed to drive anything but tube amps, with normal input impedances of 300K - 1meg. In combo's of the same brand the power amplifier input impedance was sometimes part of the coupling design, including interconnect capacitance (e.g. Quad II with Quad pre-amp),

Combining pre- and power amps with unsuitable output and input impedances is a fault, per se, of neither unit or its topology.