Audio Applications

s5000227-correction

  • Single ended or push pull class A
  • Power up to 50 watts RMS
  • Interstage
  • Line matching
  • Input transformers
  • DC chokes
  • Swinging chokes
  • Anode load chokes
  • Multiple winding for wide bandwidth
  • Multi wound HT & LT mains transformers
  • Drop through construction
  • Above chassis mounting
  • Zinc Plated or Black shrouds as standard
  • Can be custom designed to meet  your exact specifications.

Output Transformers.

The designs are specified according to their reflected primary impedance, maximum recommended dc standing current and maximum power. Frequency response is typically within 1dB from 20Hz to 40KHz and 4 and 8 ohm secondary taps are provided. The power rating of the OPT should be twice the maximum power output of the stage. Open frame, fully shrouded or drop through can be supplied as required.

Standard Range

single ended output transformers

Part No. Lam Size Stack (mm) Impedance (ohms) Primary I (mA) Power (W) Valves Bandwidth Price on application
SPE101 120 45 2K5:0-4-8 80 25 300B,2A3 15Hz-45KHz £
SPE102 120 45 3K0:0-4-8 80 25 300B,2A3 15Hz-45KHz
SPE103 120 45 3K5:0-4-8 80 25 300B,2A3 15Hz-45KHz
SPE107 29 38 2K5:0-4-8 75 15 6080/6AS7 20Hz-40KHz
SPE201 120 51 1K25:0-4-8 150 30 P300B, P2A3 15Hz-45KHz
SPE202 120 51 1K5:0-4-8 170 30 P300B, P2A3 15Hz-40KHz
SPE203 120 51 1K75:0-4-8 170 30 P300B, P2A3 15Hz-40KHz
SPE206 78 45 :0-4-8 120 25 P5881

These transformers all have multi wound primary sections for enhanced performance and bandwidth

Single ended output transformers

Part No. Lam Size Stack (mm) Impedance (ohms) Primary I (mA) Power (W) Valves Bandwidth Price on application
SPE108 120 64 2K75:0-4-8 120 30 300B,2A3,VV30B 10Hz-75KHz
SPE109 120 76 15K0:0-4-8 75 40 211 15Hz-25KHz
SPE110 120 76 6K8:0-4-8 75 40 845, SV811, SV572 15Hz-50KHz
SPE111 29 38 15K:0-4-8 30 5 71A, 10Y 15Hz-50KHz
SPE204 120 76 1K8:0-4-8 150 40 P 300B, P 2A3 10Hz-60KHz
SPE205 248 76 6K8:0-4-8 150 50 P 211, 845 15Hz-40KHz

All can have ultra linear taps at no extra cost, all can be supplied fully shrouded, open frame or drop through as required. Please enquire about any requirements not listed here.

Transformer Size Chart

transformer_designs.jpg

Lam Size A B C=(2H+G) D E=(2F+G) F G=Stack Size H
29 78 64 48 9.5 23
78 97 80 64 11.5 29
120 116 95 80 13 30
196 86 72
248 135 111 92 13 38

All dimensions are in mm

Push Pull Ouput Transformers

Push Pull Class A output transformers all feature double section bobbins for balanced primary windings and multi section primary & secondary windings for enhanced performance

Part No. Lam Size Stack (mm) Impedance (ohms) Power (W) Bandwidth Price on application
SPP101 29 37 5K :4 & 8R 15W 15Hz-45KHz
SPP102 29 37 9K : 4 & 8R 15W 15Hz-45KHz
SPP104 78 32 5K6 : 4 & 8& 16R 25W 15Hz-45KHz
SP107 78 37 6K : 4 7 8 R 25W 20Hz-45KHz
SP108 78 37 3K3 : 4 & 8R 25W 15Hz-45KHz
SPA6001 78 32 AUDIO INNOVATIONS
SPA300B 78 37 WAD 300B OUTPUT
SPA K5881 78 37 WAD K5881 OUTPUT

Interstage Coupling Transformers

The 1:1 ratio transformers have a very wide, flat, frequency response and excellent sonic characteristics. The 1:1.5 designs are more compromised, but still extend beyond 40KHz. The initial designs have been based around using the following valve types for drivers: 5687, E182CC, 417A, parallel 6SN7, parallel ECC82. Designed around a 15mA-20mA primary current, approx. 3K5 anode impedance, or below. Other drivers such as 3A/167M and ML4 have been used successfully. They can be used with a large range of output valves, including 211, 845, 300B, 6080, 2A3 etc.

Part No. Lam size Stack Size Description Bandwidth (-3dB) Price on application
SPIS101 29 38 1:1.5 ratio for SE driver to SE output valve 10Hz-40KHz
SPIS102 29 38 1:1 ratio for SE driver to SE output valve 10Hz-120KHz
SPIS103 78 38 1:1 ratio for SE driver to SE output valve 10Hz-120KHz
SPIS202 29 38 1:1+1 ratio for SE driver to PP output valves 10Hz-120KHz
SPIS203 78 38 1+1:1+1 ratio for PP driver to PP output valves 10Hz-80KHz

The 1:1 transformers offer the best high frequency extension and drive capabilities. The frequency response of the it102, for example, is 10Hz-120KHz at -3dB, there are no out of band resonance peaks or dips either which we believe is unique. They are sonically far and away the best method of coupling your driver to output, no cap is even close.The 1:1.5 are aimed primarily at high bias output valves to help reduce the voltage swing required from the driver valve e.g. 845, DA100, 6080 etc. They are capable of bandwidths over 40khZ incorrectly designed circuits

Mains Transformers

Our mains transformers are all designed using the latest CAD technology to provide good regulation (usually <5%) and optimum performance together with cool running for increased service life.

All transformers are varnish impregnated using a UL approved clear Solventless varnish which not only seals the windings against moisture ingress but also gives extremely low audible noise.

Open frame, fully shrouded or drop through types are available as requested.

Pricing for mains transformers is based upon having 3 secondary windings and the VA rating of all the secondaries added together.

VA Rating Lam size Stack Size Price on Application
75VA or below 29 or 78 as required
100VA 120 38
150VA 120 45
200VA 120 51
240VA 120 64
300VA up to 3 windings 120 76
300VA 248 51
350VA 248 64
400VA 248 70
450VA 248 76

Power Supply Inductors

Inductor smoothing is becoming popular factors, and better voltaagain as more people realise it was abandoned for reasons of cost, not quality. Inductors afford higher smoothing ge regulation, giving quieter operation and better dynamics. Using chokes enables lower values of smoothing capacitance to be used, allowing higher quality types to be specified.

The ch109 has been specially developed for use in high current, high voltage, choke input filter power supplies. Its primary use is for choke input supplies for stereo 300B amps where you may be looking at 450Vdc rails at up to 200mA. It is available only as an open frame construction, but has been built to be quieter than normal chokes in a similar supply.

Part No. Lam size Stack Size Inductance (Henries) Typical dcr (ohms) Max DC Current (mA) Price  on application
SPCH104 29 51 20 360 100
SPCH105 u clamp 30 1K8 15
SPCH106 120 76 3 15 200
SPCH107 u clamp 10 140 60
SPCH108 29 64 10 100 130
SPCH109 78 64 10 56 220
SPCH110 u clamp 12 180 40
SPCH111 120 76 50 110 120

We are the original supplier for transformers used by the following manufacturers

Arion Acoustics+Audio Innovations+Second Audio+World Audio Design

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