Quad 405 replacement transistors

This is the complete list. The original Quad transistor is in Italics our preferred alternative(s) are in Bold.

Click on the hyperlink to see the Datasheet or to buy the transistor in the Dada Electronics Webshop.

• TR1: BC214C - BC559C BC560C BC415C
• TR2: ZTX304 - BCX32 BC682 BC546B MPSA06 2N5551
• TR3/TR4: ZTX504 - BC556B
• TR5/TR6: BC214C - BC560C BC415C BC559C
• TR7/TR8: 40872 - 2SA740 BD242C 2N6134 TIP42C BDX78
• TR9/TR10: 17556 - 2SD424 2SD676 2N3773 MJ15003
• The Bridge-diode can be replaced by KBPC3504

All other Quad 405 replacement components are available in the Dada Electronics Webshop as well, or send an e-mail to info@dadaelectronics.eu.

Quad 303 replacement transistors

This is the complete list. The original Quad transistor is in Italics our preferred alternative is in Bold.

Click on the hyperlink to view the datasheet or to buy the transistor in the Dada Electronics Webshop.

• TR1: 38494 - 2N3055 MJ15003
• TR2: 38494 - 2N3055 MJ15003 (or Push-pull alternative* MJ15004)
• TR3: 40411 - MJ802
• TR100: BC154 - BC560 BC214C
• TR101/TR107: BC109 - BC109 BC237C BC184K
• TR102/TR103: U17219 - BC546B ZTX304
• TR104: U17229 - BC556B ZTX504
• TR105: 38496 - BC461 2N5322
• TR106: 38495 - BC441 2N5320
• TR200: U17229 - BC556
• TR210: 38495 - BC441
• MR 100/101/105/106 can be replaced by 1N4148

* The 303 can be modified to a PNP/NPN Push-pull amplifier using the Dada Electronics or standard boards.

All other Quad 303 replacement parts are available from the Dada Electronics Webshop or send an e-mail to info@dadaelectronics.eu.

Eduardo Niebla chooses Dada's 405 revision

We revised Eduardo's 405.

He uses it in his studio to monitor his recordings.

We used the Dada dual-mono power supply and Burr Brown OPA627 opamps.

Edouardo wrote:

"Received my Quad 405 with your upgrade plus the Velleman K4700 loudspeaker protection.

The packing was very secure, well done!

The sound now is much more open and extended; bass to trebles through the whole spectrum are very clear and rich. A very wonderful sound. I'm very very happy . I now can hear very clear my mixing and recording work in much more detail.

Thank you very much for all you wonderful and professional work - I have no hesitation in highly recommending your upgrade services and give you 10/10.

Best wishes to you all (I'm definitely a happy customer)."

Click on the picture to visit Eduardo's website.

Stefaan

Quad 50D & 50E Connectors available now

We found the original manufacturer of the 50E and 50D connectors.

The company was willing to make a small batch for us from NOS (new old stock) parts.

So these are new connectors.

The input connector for the 50E and D are the same, the output connectors are different.

Now you can restore these magnificent amplifiers to their original glory.

Joost