​Hi folk, this is Abraham and goal of my today's post is to shortlist best vacuum tube based preamplifiers that fall under the price tag of 500 dollars. An ideal preamp id the one having maximum power output and least amount of noise added in audio output. Another important feature we have kept in mind while selecting these tube based preamps is the SNR or signal to noise ratio which should be minimum. Another important thing you should keep in mind is the number of audio inputs allowed in the preamplifier.

​PAPRI is an established brand in electronic instruments. This ​pre amplifier comes with a very handy power switch which shift's the instrument from 110 volts to 220 volts. The pre amp is made up of strong aluminum chassis which has oxidative coating to increase its life and prevent it from rust and corrosion. All the inside wiring is done with pure copper wire and due to EI power transformer it has high power rate, low temperature, small size and light weight. Inside it has ERSE Audio Grade Capacitors which are​ known for reliability audio and general electrical applications. The new redesigned printed circuit board (PCB) helps shorten the length of signal wire which significantly improves quality of sound. It uses 100K TOCOS potentiometer which is known to give significant  output that does not require further amplification. Other specifications are as following

• Tubes: 2pcs Soviet poison sound 6H3
• Input sensitivity: 150mv
• Voltage output: 1.8V (RMS THD <0.03%)
• S/N Ratio: 96DB
• Frequency Response: 10Hz-50KHz (-0.5DB)
• Input Impedance: 100Kohm
• Output Impedance: 100Kohm
• AC Input: 110V/220V (switchable)
• Power Consumption: 15W
• Dimension: 240 * 140 * 120 (mm) (WDH)
• Weight: 1.8KG
  

​Vali 2 is tube based hybrid ​preamplifier that comes with single  NOS 6BZ7 tube  which makes sure that the sound to be quite clear across the entire frequency spectrum. Its most important features include switchable gain-levels and preamp outputs (switched with the headphone socket).It has two gain modes for low-noise accommodation of sensitive headphones as well as hard-to-drive headphones. Secondly it can also be used as a preamp for powered speakers or your power amp. Under the price tag of 200 dollars it is one of most affordable preamp that ensures performance-oriented tube hybrid sound​, tube input, and discrete, Class AB solid state output. 

​Most of the preamplifier ​deteriorate their performance under humidity but this preamp works perfectly even when the humidity increases from 35 to 80 percent. The output impedance is 600 ohm so the preamp will deliver the maximum amount of power without any failure. Signal to noise ratio is 90 db which means that there are very less unwanted sounds in music recording.

​Detailed specifications are as following.

SPECIFICATION

Input Power:AC100V-AC240V available 60Hz/50Hz

Output Tube: 12AT7×2, 12AU7×2, 6Z4×2

Input Sensitivity:400mV

Input impedance: 100K

Output Impedance: 600 ohm

Signal/Noise Ratio: 90dB

Frequency Response: 10Hz--30KHz

Input Jack: 4 groups

Output Jack: 2 groups

Size Dimension: W430mm x H80mm x D290mm

PACKAGE CONTENTS

The complete package contains an ​preamplifier, standard Power Cord all the tubes/Valves and original box.

​The next tube based preamp i have chosen for my blog readers is from YAQIN brand. It has high quality audio grade capacitors which make sure it produces low noise and high quality sound. SRPP preamp circuit widen frequency response and lower distortions. Signal to Noise Ratio (SNR) is ≥80db which means that the noise from electrons whizzing around inside imperceptible. Total Harmonic Distortion (THD+N) is  ≤ 2% which is vey less and a lesser value means the output ​of  amplifier is closer to ​sound of the original recording. Another great feature which makes it a perfect choice for professional recording is that it has builtin short circuit protection, overload protection and overheat protection to keep the amp and your devices functioning safely.

​Being a high fidelity amplifier it it reprodices sound without major signal loss. This tube base preamp looks very cook due to full aluminum body with wood side panel. It has builtin 4 sets of stereo L/R RCA audio input and 1 set of RCA output which is used to send audio signal to other devices. Muliple RCA audio input means that you can connect multiple inputs like PC, Echo Dot at the same time. As this preamp strictly respect the grounding line so there is very less noise produced in music recorded. Power Transformers 76 * 40 H250 0.35 make sure that the audio input signals are properly converted to AC output sound signal without the input and output being physically connected together.