It has been a long while since I've been on the forums or had any time to do any audio tinkering...the ole "real life got in the way" excuse... However, I have recently set up a headless Raspberry Pi-based RuneAudio MPD system for my digital music to sit alongside my turntable in my living room. I planned on running the output of the little USB DAC that I have attached to the Pi to my tube power amp (~25W with KT88-power tubes built from an excellent kit made by forum member scott17). However, it seems that I have to crank the power amp to ~3/4 volume to get any sort of reasonable listening volume (on the low end of reasonable). As such, I think I might need a preamp. I don't want to listen at ear bleeding volumes, but I don't want to have to crank the power amp to be able to hear anything.
As such, I think I'm in need of a preamp. I am, however, not particularly knowledgeable as to what would be a good pairing with my power amp. My questions are as follows:
1) How much gain do you think I would actually need?
2) Tube or Solid State? (Would building a tube preamp result and coupling with a tube power amp result in a little too much "tube character" imparted on the source material? Would a solid state pre be a better choice? )
3) Based on your opinions for questions 1) and 2), do you have any recommendations? Kits and non-kit schematic recommendations are welcomed!
Thanks!
As such, I think I'm in need of a preamp. I am, however, not particularly knowledgeable as to what would be a good pairing with my power amp. My questions are as follows:
1) How much gain do you think I would actually need?
2) Tube or Solid State? (Would building a tube preamp result and coupling with a tube power amp result in a little too much "tube character" imparted on the source material? Would a solid state pre be a better choice? )
3) Based on your opinions for questions 1) and 2), do you have any recommendations? Kits and non-kit schematic recommendations are welcomed!
Thanks!
Why precarious?
Unless there is something very unusual about your setup then running at a particular volume level has a certain effect on valve life. Running at the same volume via a preamp and extra attenuation (e.g. turn down the volume pot, to throw away the gain you just introduced) has exactly the same effect on valve life. There are two differences:
1. you pay for more electricity as you have an extra box to power
2. you wear out a different part of the volume pot track
Most people have too much gain. It sounds like you have just the right amount!
Unless there is something very unusual about your setup then running at a particular volume level has a certain effect on valve life. Running at the same volume via a preamp and extra attenuation (e.g. turn down the volume pot, to throw away the gain you just introduced) has exactly the same effect on valve life. There are two differences:
1. you pay for more electricity as you have an extra box to power
2. you wear out a different part of the volume pot track
Most people have too much gain. It sounds like you have just the right amount!
.
If you don't have to deal with impedance matching on your tube amp input then you might be interested in either of these Behringer units. Both go for $20-30 on eBay/Amazon. eBay is a better bet for free shipping.
Microamp HA400 is billed as a headphone distribution amp, but its Zin of 100k, and Zout of 80 ohms, make it suitable as a preamp-distribution amp.
Microphono PP400 is a single-purpose phono preamp with RIAA equalization.
Or, of course, you could build something, such as the below. But at $25 for either of the Behringers (including power supply) you gotta wonder whether it's worth waiting for the iron to heat up.
Not much. If your amp has a gain of 20, then a gain of 3 in front of it would make a total gain of 60 available. Two stages of gain adds up--or rather multiplies--fast.
These things are so very much in the ear of the beholder. Your final stage is tubes, so I personally vote that few if any would hear a difference in preamps.
.
If you don't have to deal with impedance matching on your tube amp input then you might be interested in either of these Behringer units. Both go for $20-30 on eBay/Amazon. eBay is a better bet for free shipping.
Microamp HA400 is billed as a headphone distribution amp, but its Zin of 100k, and Zout of 80 ohms, make it suitable as a preamp-distribution amp.
Microphono PP400 is a single-purpose phono preamp with RIAA equalization.
Or, of course, you could build something, such as the below. But at $25 for either of the Behringers (including power supply) you gotta wonder whether it's worth waiting for the iron to heat up.
Not much. If your amp has a gain of 20, then a gain of 3 in front of it would make a total gain of 60 available. Two stages of gain adds up--or rather multiplies--fast.
These things are so very much in the ear of the beholder. Your final stage is tubes, so I personally vote that few if any would hear a difference in preamps.
.
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