5+5 Tube Stereo Amplifier

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The PC Board, Chassis kit, output transformers and the power supply module are available for sale. Prices below are in Australian dollars less GST.

Set of main amplifier and output switching PC Boards. 
Professional quality extra thick (2mm) double sided fiberglass PC Boards with extra thick copper tracks (2oz Cu).
Easy to read component designators and values printed on board avoids mistakes. Direct mounting of all sockets, switches and potentiometers, together with screw connectors makes construction easy.

Precision cut and drilled, semi-gloss finished, and silk-screen printed chassis panels as shown in the photo above.  Made from FR-4 PC Board material with a copper surface on both sides for electrostatic shielding. Side, rear, top, and bottom panels are 2.5mm thick. The printed red front panel is 3.5mm thick. Panels are held together by eight corner brackets that also provide electrical continuity between gold flashed contact areas on each panel. Corner brackets, PC Board standoffs, and screws all included. Due to the production process the thin edges are not painted, so you may choose to run a black or red marker pen along each edge.
The result is an extremely strong, durable and good-looking chassis that fits together perfectly and costs way less that small-quantity sheet metal alternatives. For those who prefer the wooden look, you can always attach wood panels to the sides, or just use the top and rear panels in you own design housing.

This output transformer gives excellent performance in the RedRoo 5W SE design. It is epoxied into an attractive metal housing that aligns with pre-drilled holes in the RedRoo chassis. 

Single ended output transformer for Pentode, Triode and UL operation
Power Handling: 8W (30Hz),
Frequency response (no negative feedback): 15Hz-25KHz, -3dB
Primary nominal impedance: 3.5K with 30% screen grid taps.
Primary copper resistance: about 400Ω (B-P),
Primary inductance: with Measuring equipment CHROMA3302, frequency 1K inductance of 38H
Primary maximum DC current: 100mA
Secondary nominal impedance:  4/8Ω
Core Size: EI66 stack thickness 35mm,
Material: Japan Z11 steel sheet, European oxygen-free copper wire
Dimensions (mm): 83 x 68 x 90 high

(Naturally, there is no reason why you couldn't supply your own output transformers with similar specifications).             

This transformer uses a low leakage-inductance Lopent OPT featuring improved high frequency and transient response, epoxied into the same attractive metal housing as the Standard transformer. It also gives slightly higher power output and increased loudspeaker damping due to the lower DC winding resistances.
It does not have screen taps - triode and pentode mode only.

Single ended output transformer for Pentode and Triode operation only,
Frequency response: 20Hz-60KHz,-3dB(Pentode) 10HZ-75KHz,-2dB(Triode),
Power Handling: 10W(20Hz),
Primary nominal impedance: 3.5KΩ,
Primary inductance:  28H(40Hz, 5Vrms, Test machine HIOKI 3522-50 LCR Meter),
Primary Max DC primary current: 75mA (suggest 60mA),
Primary DC resistance: 215Ω
Secondary nominal impedance: 0-4-8Ω,
Secondary DC resistance
: 4 Ohm tap 0.77ohm,8 Ohm tap 1.05ohm
Metal core size:  EI76 thickness 40mm,material:  35H360(H14)
Dimensions (mm): 83 x 68 x 90 high


This assembled power supply module is used to convert 12V DC to the high voltage required for the tubes. It does not produce any 50Hz hum and, as mains power does not enter the amplifier chassis, it is safer for home constructors. Ideal for use in small Class-A amplifiers up to about 20 Watts. output.

Input voltage: 12 VDC nominal. Current load dependent. 
Output voltage: 115/200/220/280 V AC or DC selectable by links.
Output Power: 150 Watts max. Over 100 Watts requires extra cooling.
Switching Frequency: approx. 40kHz (no 50Hz hum in output).
Optional enable input (for amplifier kill-switch).
Dimensions (mm): 68 x 62 x 28 high.


 

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