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Rectifier Tubes 
274A / 274B Mesh $272
5Z3 Mesh $272
25U4G Mesh $272
280 Mesh $272
2AZ4 Mesh $313
281 half wave $272

(see notes below regarding rectifier usage)

Driver Tubes
2 20A / 20B $521
30A
$544
 20A mesh  $567

8

Output Tubes

1 45 $510
 
45 Globe $725
45-Mesh $629
1 50 $743
2A3-S $567
2A3-Mesh $629
300B $572
2 300B Mesh - $810
300B-XLS $742
320B-XLS $777
AD1-mesh  $845
520-V2  $1015
520- V3 $992
important update 1605  - $1083
     Tube base glue for repairs


2 About filament quality
Specific items with some amplifiers

WARNING FOR FAKE
MESH TUBES
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                        FORUM
All tubes priced per matched pair.
Rectifiers priced each.
Prices are subject to change due to currency exchange rates.

To order: info@tubesusa.com
or call (516) 902-3334






Note 1)
Good care should be taken when making the design of any DH rectifier. It must be prevented to have strong current peaks, through the first capacitor, because consequently this flows through the tube anode, and transformer windings as well. The transformer will produce mechanical hum by this, most specially if windings symmetry fails. Also the tube will suffer. For this reason, the first capacitor (C1) should never be larger than stated in the data sheet.   The mechanical transformer hum, and also tube current peaks are greatly reduced by smaller capacitor values, and use higher choke values instead. Although higher capacitor values are at lower cost, using lower capacitors and higher chokes values instead, is always more satisfactory in the end. The result will be: Lower transformer hum, less electrical field radiation into the pre-amp, and more lifetime from the rectifier tube. This is why we recommend using largest chokes. From Lundahl, high value chokes are available at the same price as HiFi capacitors, like from a Mundorf or Black Gate. So we have to go back to the roots, and use high quality, large value chokes, like in the old days of radio design. For best ripple suppression, increase the choke to any value you need, or even use a C-L-C-L-C circuit, as also advised in the historical RCA data sheet.

Note 2) Higher capacitor values up to 20uF can be used, if you work at lower voltage and lower current than maximum. This will be the case for instance with smaller amplifiers, such as using the 45 tube.

Note 3) As a rule of thumb, high voltage power supplies are best built with large size chokes, especially at high output current, whereas low voltage power supplies can be built more easily with large capacitors.

Note 4) Winding symmetry is needed with HV transformers to prevent hum. A HV winding with center tap, requires FOUR separated HV windings inside the transformer, which are arranged for the end user as TWO windings which are in series. It is remarkable to see that this is widely unknown today by many transformer manufacturers. Also this is more expensive. So often, they build tube rectifier windings only from two internal windings, and not FOUR windings as needed for tube rectifiers. However we have a tube data sheet here, no transformer construction manual, so we can not explain this in more detail.