DISCLAIMER: Vacuum tube circuits work with dangerously high voltages. Do not attempt to build circuits presented on this site if you do not have the required experience and skills to work with such voltages. I assume no responsibility whatsoever for any damage caused by the usage of my circuits.

All rights of photos and text reserved. Usage of photos or text from my blog on other websites or for any other purpose only with prior permission. If you want to use any material from my blog please contact me by email.

Tuesday, July 25, 2017

Hong Kong High-End Audio Visual Show 2017


I am happy to announce the presence of ELROG tubes and my amplifiers at the Hong Kong High-End Visual Show 2017 from August 11th to 13th.

This exhibition is hosted by audiotechnique in the Hong Kong Convention and Exhibition Centre. Our participation is organised by Baoling Alternative Audio.

Come to hall 3, booth A07 to see some of my amplifiers and and listen to ELROG tubes.

Looking forward to meeting you in Hong Kong!

Best regards


Friday, July 21, 2017

The Tweeter Amplifiers, Part 2


In part 1 I showed the tweeter amplifiers half way through assembly. Here are some photos of the finished amps.

These are mono blocks each with it's power supply on board.

Output tube is the 801A, driven by a 6N7.

A 6BY5 located at the back side does the rectification.

Top view:

Both amps together:

Although designed as tweeter amps for an active set up, these could be used fully range with speakers which do not have deep bass anyways. Roll off kicks in below 60Hz

Best regards


Thursday, July 13, 2017

Summer Sale


I need to clear out some parts of which I have too many in stock and which are not planned for projects in the near future.

These Lundahl transformers are up for sale at discounted prices. The list prices per piece are given for each item. This is the net list price for export outside the EU. Inside the EU 19% sales tax is added. For a purchase of one pair subtract 20%. 25% discount when buying 2 pairs at once, 30% for 4 pairs and 40% for 5 pairs or more. A mix of any of the listed types can be ordered to apply for the discounts. The offer is valid only while supplies last. Send an email for a total quote including shipping. Payments can be received by bank transfer or PayPal.

LL2753 large interstage transformer 1:1 (list price 120,- Euros per piece)

available with different air gaps for these currents:
25, 30, 35, 40, 50 mA

LL2745 interstage or line out transformer 2.8 + 2.8 : 1 + 1 + 1 + 1 (list price 105,- Euros per piece)

available with different air gaps for these currents:
11, 18, 36 mA

LL1692A interstage or line out transformer 1.75 + 1.75 : 1 + 1 + 1 + 1 (list price 92,- Euros per piece)

available with different air gaps for these currents:
10,  36 mA

LL1689  line out transformer 9 + 9 : 1 + 1 + 1 + 1 (list price 105,- Euros per piece)

available with different air gaps for these currents:
18, 25, 36 mA

LL1694 filament choke (list price 64,- Euros per piece)

available for these currents:
1.25, 1.0, 0.75A

I also have some horns lying around unused, maybe you can bring them to good use:

Aluminium cast IWATA horns for 2 inch drivers painted in metallic grey.

1.500,- Euros for the pair.

These are quite heavy so shipping cost can be quite high. Personal pick up can be arranged.

Elliptic horns made by David Haigner.  Painted in silver/champagne metallic with a slight tint of green.
These are made of plaster and come with adapters to reduce the mouth opening to 2 inch. Holes for mounting the adapters and drivers need to be drilled by yourself.

750,- Euros for the pair.

Best regards