Building a vacuum tube amp vs a solid state amp
Posted 22nd April 2015 at 11:35 AM by cspirou
This is my article about comparing vacuum tube amps vs SS amps. There are more than enough places that compare there two types from the aspect of sound. I will avoid that and only concentrate on the differences from a DIY aspect.
Solid state amp pros
*Transistors are cheaper than vacuum tubes
*PCBs are available for many amps
*Transistors are usually more reliable and last longer
*power supplies use lower voltages than tube supplies and therefore are much safer. also no need for a separate heater supply
*usually don't need output transformers
*chassis work is typically limited to front and rear panel
Solid state amp cons
*Often necessary to buy a large heatsink
*If no PCB is available, designing and making your own PCB can be cumbersome
*If you don't use a PCB, point-to-point wiring is very difficult
*Need to be careful with electrostatic discharge. Easy to fry a transistor if you aren't grounded.
*power supply design is can be a bit more complicated since you need dual rails for many designs
Vacuum Tube pros
*Thermal management is much easier with tubes because they are usually cooled passively without an additional heatsink
*point-to-point wiring is feasible with tubes
*circuit topologies are typically simpler
*electrically tubes are not as fragile as transistors and don't have to worry about static discharge
*vacuum tubes are much easier to service over transistors. You don't even have to open the chassis or use any tools to change a vacuum tube
*power supplies are usually simpler single rail supplies
Vacuum tube cons
*mechanically tubes are much more fragile then transistors. May need a cage for protection
*Tubes have a shorter working lifespan compared to transistors and need to be changed often
*power supplies use dangerous high voltages. an additional supply is also needed to heat the tube filaments
*high output impedances mean the need for expensive and heavy output transformers
*enclosures need more work to attach tube sockets and transformers
Based on this I think I will build an OTL headphone tube amp but will build solid state speaker amps.
Solid state amp pros
*Transistors are cheaper than vacuum tubes
*PCBs are available for many amps
*Transistors are usually more reliable and last longer
*power supplies use lower voltages than tube supplies and therefore are much safer. also no need for a separate heater supply
*usually don't need output transformers
*chassis work is typically limited to front and rear panel
Solid state amp cons
*Often necessary to buy a large heatsink
*If no PCB is available, designing and making your own PCB can be cumbersome
*If you don't use a PCB, point-to-point wiring is very difficult
*Need to be careful with electrostatic discharge. Easy to fry a transistor if you aren't grounded.
*power supply design is can be a bit more complicated since you need dual rails for many designs
Vacuum Tube pros
*Thermal management is much easier with tubes because they are usually cooled passively without an additional heatsink
*point-to-point wiring is feasible with tubes
*circuit topologies are typically simpler
*electrically tubes are not as fragile as transistors and don't have to worry about static discharge
*vacuum tubes are much easier to service over transistors. You don't even have to open the chassis or use any tools to change a vacuum tube
*power supplies are usually simpler single rail supplies
Vacuum tube cons
*mechanically tubes are much more fragile then transistors. May need a cage for protection
*Tubes have a shorter working lifespan compared to transistors and need to be changed often
*power supplies use dangerous high voltages. an additional supply is also needed to heat the tube filaments
*high output impedances mean the need for expensive and heavy output transformers
*enclosures need more work to attach tube sockets and transformers
Based on this I think I will build an OTL headphone tube amp but will build solid state speaker amps.
Total Comments 4
Comments
-
Another difference is that transistor amplifiers typically operate in voltage, and tube amps operating in current.
Maybe a design like this can resolve the dilemma, and has the advantages of transistors and valves:
https://www.diyaudio.com/forums/chip-...ml#post3564061Posted 22nd April 2015 at 05:57 PM by raul_77
-
Well my post was more about what I need in order to execute a build. Not so much the sort of amp I am looking for. I am very interested in building a transconductance amp though.Posted 22nd April 2015 at 07:12 PM by cspirou
-
For power amps, I think tube circuits make easier diy projects. Typically point-to-point wiring, lower parts count, lower bandwidth, lower feedback. Less debugging, less worry.
With transistor power amps you need to add reliable thermal and over-current protection, and test the heck out of it for stability into the worst possible case loads. Ok, you could use a pre-designed module and hope that its all worked out for you, just add power supply and heatsinks... but there's less satisfaction in that, since its basically just component assembly.
Transistor power amps are fun if you really get into it, do the design and testing yourself, but that's a step above doing the same kind of thing with tube amps in terms of complexity and investment.Posted 30th April 2015 at 12:07 PM by rjm
-
I totally agree. The simplicity of tube circuits and point to point wiring make it much easier to get into. The only real barrier for me is the cost of output transformers. Which is basically why I want to start with an OTL headphone amp.Quote:Originally Posted by rjm
Transistor power amps are fun if you really get into it, do the design and testing yourself, but that's a step above doing the same kind of thing with tube amps in terms of complexity and investment.
I am starting to realize that it might not be that much cheaper to DIY as I get deeper in this hobby. Though I will still retain the fantasy that I am saving money building circuits and price/performance ratio remains near the top of the things I value in a DIY project.Posted 14th May 2015 at 06:13 AM by cspirou
