Price Increases on “Other Kits”

After much deliberation I have made relatively minor increases in the prices of the support kits that I have offered since the beginning of K&K Audio in 2003. The price for the earliest of these, the Basic Current Source Kit, has never been changed! Transformer prices will remain as they are for at least 7 more months.

New Lundahl Audiophile Transformer and PS Chokes

Lundahl Transformers will shortly announce the availability and pricing for three new parts.  The data sheets are linked below:

LL2766 – a compact (LL1660 size) low power output transformer for tube amplifiers, SE or PP.  Think SE 45/46/47 or PP 6V6GT and many more low power possibilities…

LL2771 – a big (1A, 3H) power supply choke.  Would have been great for my PSE6C33C amp power supply….

LL2772 – a low resistance filament current choke (3A, 80mH).  Perfect for the Russian GM-70, for example.

Gerus Audio is using Lundahl Transformers in their Amplifiers

Scott Gerus has been building tube amplifiers for some time now, but recently retired and has created a website ( to make his designs more broadly available.  He has designed and built several monoblock and stereo single-ended and push-pull amplifiers, which can be viewed on his website.  Interestingly, he does the woodworking and metalworking for his products himself!  Have a look.  These aren’t simple aluminum boxes with tubes and transformers parked on the top!  (like I build for myself…)

After using Lundahl output transformers in a few amplifiers over the past two years, he recently posted on his website:

“Over the years I’ve used Hammond, Electra-Print, Transcendar and Pliton OPT’s.  The only one that comes close to the Lundahl is Plitron, and they cost twice as much and take up 3 times the space!

You can’t beat the Lundahl’s for the Price!”   We agree, Scott!

Erhard Audio uses Lundahl Output Transformers in their designs

We are happy to note that Erhard Audio (formerly Tube Nirvana) has auditioned Lundahl amplifier output transformers in their models and, as a result, are using Lundahl output transformers now in production.  You can read their take on these and other parts decisions here: and see power the amplifiers here:

and a headphone amplifier:

And while you’re at it, look at the chassis artistry, as well!

New Lundahl Catalog Available

Lundahl Transformers has compiled a new catalog in .pdf format that is downloadable from their website.  It includes data sheets for the newest models, as well as the older ones that we have relied on for great sound over twenty years.  It can be viewed or downloaded here:

Fall Inventory Reduction Sale on Raleigh Audio Products

Dave Davenport of Raleigh Audio has announced a Fall inventory-reduction sale. While inventory lasts, assembled DACs and Preamps are being offered at a 20% discount.

As is usual, the Preamps are a fixed configuration, while the input configuration of the DACs are custom. Below are listed some sample configurations with their sales prices. You can order those configurations for the prices shown or ask for a quote for a custom configuration. Use the sample configurations for a ballpark idea of where the price of a custom configuration might come in.

In addition, there is one unit that was built to prove the documentation and provide pictures for the website. This is a fully configured Standard “DAC #4” configuration and is offered at a 30% discount – an additional savings of $300. Because this unit is already built, the input configuration cannot be customized.

Further details for these DACs and Preamps can be seen under the “Products” menu on this site.  Please ask if you have questions.  Don’t miss this opportunity to own a custom configured Raleigh Audio product at a great price!


Item Sales Price
DAC #1 (Standard)
DAC #2 (Standard)
DAC #3 (Standard)
DAC #4 (Standard)
Special – one only
DAC #4 (Standard)
DAC #5 (Premium)
DAC #6 (Premium)
DAC #7 (Premium)
DAC #8 (Premium)
Preamp #1 (Standard)
four (single-ended RCA), two (balanced XLR)
Preamp #2 (Premium)four (single-ended RCA), two (balanced XLR) $2879

Monoblock PP Amplifier Using New Amplifier Kits

I’ve designed and begun the assembly of a PP KT120/150 monoblock amplifier that uses the new capacitor-coupled 6J49P PP input stage and one of the new power supply kits.  The power supply is choke input for low noise and uses a lower cost, over-sized toroidal power transformer.  The output stage is operated Class A1 with a common current source in the cathode circuit (on the heat sink at the back of the chassis) and can be switched between triode and “ultralinear” operation.  The chassis (20″ x 10″ x 3.2″) is made from Par-Metal Products 10 series sides and backs, with an aluminum top panel (0.09 inches thick) drilled by me and powder coated locally in “satin black”.

PP monoblock assembly

PP monoblock assembly

As you can (barely) see in the schematic below, there are relatively few components off of the PC boards, making wiring a straightforward task.  I’ll post more info as the build continues.

Capacitor-Coupled 2 Stage PP Class A1 Amplifier


New Interstage Transformers Designed for Single-Ended Amplifiers

Lundahl Transformers has quietly introduced a series of new transformers that were designed specifically for SE use as interstage transformers. While the LL1660, LL1692A, and LL1671 have been great transformers in my hands and in those of many others, there was performance to be gained by designing new transformers whose winding geometry has been optimized solely for single ended drivers and output stages.

These are the part numbers, prices, and their turns ratio data. Data sheets can be accessed from the data sheet menu.

Part                  Turns Ratio         Price (USD)

LL2746                   1:2                        $145

LL2753                   1:1                        $145

LL2756                   1:1                        $145

LL2762                   1:1                        $110

The LL2746, LL2753, LL2756, and LL2762 are also available with amorphous iron cores and/or silver wire coils at higher prices.

The LL2746 and LL2753 are designed to work with lower plate impedance tubes than the LL2756 and LL2762. The LL2756 and LL2762 are similar in application, but the LL2756 is larger and has a lower winding resistance for a given amount of primary inductance than does the smaller LL2762 (same size as the LL1660).

Audio Transformer Basics 101

We’ve added a new series of reference documents under the “Transformers” menu heading, labeled “Transformer Basics 101”.  These articles were developed and authored for Lundahl Transformers by a well-known pro audio designer, Ken DeLoria.  These provide an excellent introduction to audio transformers:  rationale for use, applications examples, construction/manufacturing, and a bit of transformer theory and math.  Please feel free to browse these six “white papers” and take away information that can help you design better audio equipment.