Hello!
I was hoping to find a DIY or prebuilt tube preamp board for my existing DIY "premp", which consists of an input selector board with ALPS pot, a power supply and a buffer to convert to balanced output. Since my knowledge is very limited I have a few questions before I get started. Most of them I can ask later but the most important one is this:
Does it make any sense at all? My thinking is that I already have a nice input selector and buffer and that there are probably existing boards I can add between the input selector and the buffer?
My electronics knowledge is limited but apart from small smd parts I'm OK with soldering and have completed a DIY powe amp and other projects in the past.
Thanks for your time
I was hoping to find a DIY or prebuilt tube preamp board for my existing DIY "premp", which consists of an input selector board with ALPS pot, a power supply and a buffer to convert to balanced output. Since my knowledge is very limited I have a few questions before I get started. Most of them I can ask later but the most important one is this:
Does it make any sense at all? My thinking is that I already have a nice input selector and buffer and that there are probably existing boards I can add between the input selector and the buffer?
My electronics knowledge is limited but apart from small smd parts I'm OK with soldering and have completed a DIY powe amp and other projects in the past.
Thanks for your time
I'm not very familiar with buffers, other than cathode follower stages in tube preamps, although I've never used one. I'm even less familiar with balanced outputs. Is it a tube buffer or SS? Do you simply run a line level signal from the selector into it?
I'm not sure if there might be an impedance matching issue or not.
I'm not sure if there might be an impedance matching issue or not.
Which power amplifier, and which kinds of sources do you use?
And yes, which kind of buffer?
And yes, which kind of buffer?
If I'm tracking, you are looking for a preamp pcb that uses vacuum tubes supplying some gain that will be inserted between the input selector and an output buffer. I'm assuming the output buffer is solid state and you are looking to add a bit of gain or some tube sweetness.
If so, one place to look would be John Broskie's GlassWare website: https://glass-ware.stores.yahoo.net/listheam.html
If so, one place to look would be John Broskie's GlassWare website: https://glass-ware.stores.yahoo.net/listheam.html
Hello! I'm using all neurochrome parts for the preamp amd a neurochrome mod-86 power amp. I don't have the buffer yet but it's also going to be a neurochrome universal buffer.
Me neither, but i thought a buffer might be a good idea because of the impedance issues. There are diferent designs you can build, with or without the buffer. The buffer is a solid state model. Apart from that it is just a line level signal from the sources through an input selector followed by the buffer:
Question would be how much maximum voltage can be put on the input of the buffer. Cursory look thru the spec, it is designed expecting 2Vrms. Don't know what will happen if you go bigger. There is note that a resistor change will yield more gain. Not sure there is more detail on the specifics in any paperwork you have.
Fair point! Perhaps the tube configuration wouldn't benefit from the buffer. But hey, this is why I'm asking these questoins. How would a power amp cope with the possile output impedance of a tube preamp withaout any additional buffers?
depends on the design. most any vacuum tube preamp will drive a solid state amp, especially if the final stage of the preamp is a cathode follower. What's the input impedance for the amp in question?
Not familiar with that amp design and, yeah, don't see the input impedance in the spec list. The amp is stated as having a gain of 20. This would mean picking the circuit topology, tubes and operating points will need to be figured out so you don't overdrive the output stage of the amp.
As Rayma suggest, might be best to ask the designer at this point.
As Rayma suggest, might be best to ask the designer at this point.
I think it's a gain of 20db or 10x but it can be changed with a different choice of resistors. Tom chose a 10x gain to keep the noise down if I remember correctly.
But from your post I'm starting to think that chosing a solution isn't as easy as I thought. I was under the impression that it would be rather universal. I wouldn't think much about this if i went to buy a tube preamp in a shop.
I hear ya.
pro gear has a bunch of standards that help with matching equipment. Then again, need to be able to set levels and all that stuff or you're waisting studio time.
Home audio, more dependent on the dealer knowing what equipment plays well together or spending much time reading and understanding specs.
pro gear has a bunch of standards that help with matching equipment. Then again, need to be able to set levels and all that stuff or you're waisting studio time.
Home audio, more dependent on the dealer knowing what equipment plays well together or spending much time reading and understanding specs.