The heart of Marantz 7 M7 line amp is a two common cathode stage with negative feedback followed by a cathode follower. The design is simple with few components, but both the tone control and filter circuit deteriorates the sound details a lot also so many switch contacts inserted further down grade the sound…
Triode single end amp’s warm sound but less power leads Diyers to find other solution. Tetrode push pull amp gives larger power but sounds no good. Compare tetrode and triode plate curve please see picture: The output area is much bigger for tetrode as well as output power, but the price pay for that is…
A RIAA network gain is equal to its impedance ratio. Zout/Zin in absolute values: We start from a RC parallel network: Zout network is R1 C1 parallel with C2 in series: Zin network is Zout with R2 in series: The result will be: Actual Actual Standard gain response Forward RIAA 20Hz 0.9313 19.55 db 19.5…
RIAA RC basic RC network principle is simple please see picture: (RIAA RC basic network) In low frequency C almost open then 9R and R deliver 0.1Vin to output. In high frequency C almost shorted circuitand deliver 1Vin to output. F1 and F2 are known as turning frequencies which determined by R and C time…
This article is talking about SRPP tube amplifier and touching the key points. The actual experiment support can prove the theory. The amp itself is simple just two triodes V1 and V2 connected in series to share one B+ power supply. Where there is no input signal V1 and V2 have same plate current and…
Long tail phase splitter (also known as Cathode Coupled Phase Splitter) is widely used in push pull tube amp driver stage, it is more convenient and simple but the output voltage has about 10% difference between V1 and V2, to use a larger value resistor as V2 plate resistor is a norm in long tail…
From 1920 to 1960 was the golden age of vacuum tube era. Lots of excellent triodes created from USA and Europe. Some of them originally designed for radio transmitters were widely used in world war II whilst the others worked for audio amplifiers. I collect direct heating triodes for fun and, however, they go together…
I collect direct heating triodes for fun and later found they are very good for single end audio power amplifiers. I’d like to test different output tubes so I build a stereo single end experiment platform to facilitate them. The concept is simple, I use independent power supplies: 1. 0-1200V 450ma DC variable to fit power tube…
Telefunken was a famous German company started at 1903, and soon became leading company in Europe, they demonstrated radio transmission of music in 1907, then built the first tape recorders in mid-1930’s and made the first television broadcasting in 1936 Berlin Olympic games. They made high-quality tube radios, tube amplifiers and vacuum tubes in mass…