Power Tube

Can I replace a power tube in a guitar amplifier without matching it to the existing power tubes?

I just bought a vintage amp and it has 3 Mullard EL34’s but is missing the fourth. I have read that if i get a fourth and don’t get it matched it will compete against the existing tubes. I eventually want to get a 4th matched tube and the other 3 tested but i want to turn the amp to make sure it is functioning properly as it is before investing in new tubes. Is it okay to play through it at low volumes with just the 3 tubes and/or can i get away with putting in a cheap EL34 in the empty slot to play for a little while before getting the 4th matched Mullard?

Most high end audio products using tubes require matched tubes for two reasons:

1. Sound quality
2. Electronic reasons.

The best case scenario – the mismatched tube will be relatively close to the installed tubes, and you’ll have some distortion and poor sound quality.

Worst case scenario – the mismatched tube will be so far out of spec with the other tubes that it will lead to a lot of distortion, feedback, etc, and it will permanently damage some of the other electronic components in the amp.

Best advice – see if there is someone local who has a spare set of tubes that you can borrow to do your initial tests, then invest in a set of matched tubes afterwards.

If you really want to cheap out and not buy all four tubes, at least buy matched pair, and replace two of them. They are generally used in pairs – but you will need a schematic and someone with experience to tell you which two are paired with each other.

EIMAC 304TH Power Triode Tube Made in USA – NOS $149.99

EIMAC 304TH Power Triode Tube Made in USA – NOS $149.99

Heathkit SB-102 & SB-600 tube ham radio transceiver & power supply / speaker $10.49

Eimac 4CX1000A / JAN8168 High Power Amplifier Tube Collins 30S-1 $50.25

Eimac 3-400Z Triode Transmitter Power Tube – used $9.99

Eimac JAN-8188/4PR400A/4-400 Electron Power Tube dated 7523. Good for display or $9.95

Two Eimac JAN 4CX250K 8245 Ceramic VHF/UHF Power Output Electron Tubes. Tested $24.95

NIB Eimac 4-250A Power Tube $40.00

Eimac 4CX300A metal-ceramic RF power output tube NOS / NIB ***FREE SHIPPING*** $99.00

4-1000A/8166 power tetrode transmitting tube – excellent – likely made by Penta $99.00

new antique eimac power tube 4-400 $26.55

14 EIMAC 4X150A (7034) POWER TUBES – Tetrodes $29.99

TWO RCA DRAKE AMPLIFIER POWER TUBES TYPE 6146 / 6146A BLACK PLATES TESTED GREAT! $99.99

RCA YASEU / DRAKE POWER TUBES 6146A / 6146 AND 12BY7 TESTED EXCELLENT VINTAGE $99.99

Eimac Amplifier Varian Tube Radial Beam Power Tetrode $480.00

Vintage Eimac 4-250A HAM Radio Transmitter Power Tetrode Tube JAN-CIM-4-250A $50.00

GS-23B Power Tube $150.00

WWII era EIMAC VT129/304 TL Triode TRANSMITTER POWER TUBE for HAM RADIO etc $20.50

WWII era SYLVANIA VT129/304 TL Triode TRANSMITTER POWER TUBE for HAM RADIO etc $15.50

WWII era SYLVANIA VT129/304 TL Triode TRANSMITTER POWER TUBE for HAM RADIO etc $22.50

4662 Power Tube 380W Linear Beam Power tube Burle 2pcs. NOS $82.00

Vintage RCA 6JE6 A Gray Plate Power Tube – Tests Excellent $1.25

Dentron GLA-1000C HF Ham Linear Amplifier Amp Tube Power GLA 1000 C $330.50

GS-35B Tube W/O cooler for power amplifier EME VHF UHF QRO $120.00

Eimac 4X150 G / 8172 power tube NOS $10.00

VANTAGE 833A POWER TRANSMITTING ELECTRON TUBE I THINK?? NO RESERVE BID TO WIN $9.99

GS-35B 2,5kW Power Tube. NEW IN BOX! $189.50

Vintage EIMAC JAN 7034 4X150A Output Power Tube $0.99

Quad Lot of RCA JAN 7558 Black Plate Power Tubes $1.29

Freed Power transformer for tube amp 600V-200mA!! (T-102 / no. 16624) $89.90

High Voltage Power transformer for tube amp 1100V at 210mA!! $89.90

High Voltage Power transformer for tube amp 700V and 460V at 200mA!! + Filament $89.90

1 CBS Hytron 5514 Power Triode Tube ~ Upgraded 811A $45.00

motorola 6583382d02 oem NIB tube power tetrode 8560a $50.00

Teaberry Tube Type CB Radio 40 channel Power Cord Only $14.98

One RCA Blackplate 7868 guitar hi-fi home audio power tube vintage audio $66.00

6JB6A GE Beam Power Pentode Tube NEW $40.00

Varian 01008290-03 TWTA Tube Amplifier Power Supply $999.99

Old Vacuum Tube Radio How To Plan Regenerative Receiver Power Supply Book Photo $18.67

GI-39B VHF 150kW pulse Power Tube. New in Box! $109.50

GE GL-6771 RF Power Amplifier 4GHz Radio Frequency Multiplier Tube Ham Radio $139.99

RCA JAN 832-A Push-Pull RF Beam Power Amplifier Tube – Balanced Triodes $25.00

JAN 7034 4X150 New VHF Ham Radio Power Amplifier Tube $45.95

1 NOS Eimac JAN 4CX300A / 8167 RF Power Tube NIB $75.00

QB3/300 C1108 RF power output tube / NIB / NOS / FREE SHIPPING $69.95

6JS6B Realistic Compactron Beam Power Pentode Tube NEW $50.00

Vintage Gates Tube Broadcast Console Power Supply $299.00

Varian 9250vdc 12kva Power Supply for Klystron RF Tube $4,195.50

TWO NEW OLD STOCK G.E. M2057 / 8950 RF OUTPUT POWER TUBES – FREE SHIPPING $99.99

1) MOTOROLA 97-136A01 (8643) POWER TUBE – “DUAL” Tetrode VHF/UHF // SALE!! $10.00

Make-up Air System – Power Tube Fan

Tenderall Fan Co. has developed one o'clock PT Tube Power Make-Up Air System – one of the cheapest options for large industrial plants ventilation air make up systems.

PT Air Make-Up fan system is a concept of forced ventilation. Use some of the aerodynamic principles for supplying, tempering and distributing make-up air in a building in cold weather. Provides greater efficiency, economy and comfort than most conventional make-up air.

When fans are used to provide ventilation, both for the process industrial exhaust and personnel comfort, a negative air pressure created inside the building. This negative pressure causes several problems:

— Process exhaust systems are less efficient and can not function properly.
– Down flow can occur through gravity vents and result in the back ventilation of the combustion products of the ducts and stacks of heaters and process equipment.
– The projects are created that are a dsicomfort employees. Of safe operation of exterior doors may even be affected.

Our fan power tube Make-Up Air System solves all of these economic problems, even in the coldest days of winter.

PT Fan fan system consists of a specially designed air supply a wall of the housing and a damper motor air inlet. A long polyethylene tube attached to the unit and extends horizontally into the building's support wire. Precision has holes punched on both sides at specific intervals along its length and has a closed opposite end.

Each set of fan housing is mounted on the exterior wall opening or connected to a ceiling fan air supply.

In the winter, conventional make-up air systems have to heat the cold outside air before introduction into the building. This is costly both in equipment and ongoing energy costs. The Power Tube Fam Make-Up Air System is a simple system that uses heat waste3d construction and basic principles of earodynamic for the supply, nerve and distribution makeup air. And that makes it less expensive than conventional make-up air systems to purchase, install and operate.

When the makeup air is needed, the shutter opens the entrance to the engine, the fan turns on and power supplies fresh outside air to inflate the tube along its length. The discharge of air holes in the tube generally located as small high-speed jets create turbulence that mixes with the warmer air inside. As a result, the outside air is tempered before effective reach the level of workers, creating a uniform draft free up the air system.

Usually PT fans several systems are needed for building, depending on the size of the building, the volume of makeup air required, the size of models selected Fan PT. Additional heating, if necessary, can be supplied in the conventional unit heaters type of space located close to the PT distribution pipes.

Air Makeup system Tenderall PT has the following advantages over air makeup coventional:

* Provides savings in initial investment and operating costs;
* Provides Draft free air distribution and uniform along the tube instead of air jet from a single source output;
* Uses less energy due to lower power for same volume of air supplied and because friction loss of blowing air through a heat transfer system is completely removed;
* More easier and less expensive to install, as PT fan system is relatively light in weight ans polyethylene pipe can be installed in a fraction of time normally required for conventional ventilation ducts;
* Eliminates coil freeze up AHU typical problems with heating, hot water and heat exchangers steam;
* Recover lost heat load in most buildings – through the outside air mixing with hot air inside;
* Very quiet, normally within 20 Sones Fan;
* Flexible capacity, which is achieved by implementing only the necessary number of units of PT on the basis of the temperature inside the building;
* Provides a more comfortable environment for electronic work, maintaining the smooth airflow and temperature distribution uniform.

Tube Power Make-Up Air Fans are available in sizes from 18 to 48 for air flows up to 40,000 CFM.

PT Power Tube Makeup air duct system is constructed of high density woven polyethylene fiber thickness (8 x laminated with polyethylene coating with a thickness of 6 mils. It is 3.8 ounces per square yeard material. Breaking strength is 118 pounds per square inch. The material is flame retardant and comply with NFPA 701. The tubes are Available in two colors: blue and white. One end of the polyethylene pipe factory dealed.

Adequate makeup air be provided to balance general exhaust ventilation and process ventilation. Usually several Power Tube Fans will be necessary, which is air distribution throughout the plant. If additional tempering of makeup air in specific plant areas is necessary, the unit heaters can be added.

Information Additional information may also fan web Tenderall http://www.tenderall.com/ahu/index.html company site.

Oleg Chetchel
Air Systems Engineer
Tenderall Fan Co.
http://tenderall.com/inquiry/index.html
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About the Author

Oleg Chetchel
Ventilation Equipment Designer
Tenderall Fan Co.
http://tenderall.com