My offer are ultra low distortion amplifier DiY kits at a non-profit price until further notice, sold through Ebay, payed with Paypal.
Condition for resorting to the non-profit price: send me photos of the completed amp that I can post on my homepage within 6 months of purchase.
All kind of distortions are surely much lower than what can be sensed by human hearing (e.g. 1kHz THD<0.001%). 6 prototypes were built and all function perfectly. ABX blind tests and nulltest prove no "sound of its own", neutral and transparent. Can be used as reference amplifier or loudspeaker measurement amplifier, too.
LDA MIN: 2x80 Watts stereo with turn-on thump muting via a mechanical relay (the mechanical relay may somewhat degrade distortion), no protections. 75 EUR + shipping.
LDA DM1: 2x120 Watts dual mono with full protections via ultra low distortion solid state relays. 140 EUR + shipping.
LDA DM2: 2x200 Watts dual mono with full protections via ultra low distortion solid state relays. 178 EUR + shipping.
LDA MON: 1x200 Watts mono with full protections via an ultra low distortion solid state relay. 90 EUR + shipping.
Outside of Europe shipping costs may be prohibitive. The above non-profit prices include packaging fee, Ebay commission, and Paypal commission. Currently on Ebay in the UK, Germany, France, Spain, Italy. If you're interested and the kit is not listed on the Ebay of your country, please write me a private message. If there is no Ebay in your country or you don't have Paypal, then you can't buy safely from me.
All components are from reliable source. Critical components are from renowned manufacturers.
More information: DiY loudspeaker and amplifier design
LDA home
Please check what is included in the kits and what is not.
Condition for resorting to the non-profit price: send me photos of the completed amp that I can post on my homepage within 6 months of purchase.
All kind of distortions are surely much lower than what can be sensed by human hearing (e.g. 1kHz THD<0.001%). 6 prototypes were built and all function perfectly. ABX blind tests and nulltest prove no "sound of its own", neutral and transparent. Can be used as reference amplifier or loudspeaker measurement amplifier, too.
LDA MIN: 2x80 Watts stereo with turn-on thump muting via a mechanical relay (the mechanical relay may somewhat degrade distortion), no protections. 75 EUR + shipping.
LDA DM1: 2x120 Watts dual mono with full protections via ultra low distortion solid state relays. 140 EUR + shipping.
LDA DM2: 2x200 Watts dual mono with full protections via ultra low distortion solid state relays. 178 EUR + shipping.
LDA MON: 1x200 Watts mono with full protections via an ultra low distortion solid state relay. 90 EUR + shipping.
Outside of Europe shipping costs may be prohibitive. The above non-profit prices include packaging fee, Ebay commission, and Paypal commission. Currently on Ebay in the UK, Germany, France, Spain, Italy. If you're interested and the kit is not listed on the Ebay of your country, please write me a private message. If there is no Ebay in your country or you don't have Paypal, then you can't buy safely from me.
All components are from reliable source. Critical components are from renowned manufacturers.
More information: DiY loudspeaker and amplifier design
LDA home
Please check what is included in the kits and what is not.
distortion measurements and nulltest
Some measurements done with ARTA. 2.8V peak output signal was chosen because the crossover distortion is significant in this voltage range (and normal listening volume with an average sensitivity speaker is also a few volts).
The ultra low distortion can be spoiled by changing two resistors, and so a distortion profile similar to that of tube amplifiers will result (see 4th attached image).
A nulltest has proved that this amplifier has no audible distortion. Nulltest difference file can be downloaded near the end of the following page: The LDA low distortion audio power amplifier project
Some measurements done with ARTA. 2.8V peak output signal was chosen because the crossover distortion is significant in this voltage range (and normal listening volume with an average sensitivity speaker is also a few volts).
The ultra low distortion can be spoiled by changing two resistors, and so a distortion profile similar to that of tube amplifiers will result (see 4th attached image).
A nulltest has proved that this amplifier has no audible distortion. Nulltest difference file can be downloaded near the end of the following page: The LDA low distortion audio power amplifier project
Attachments
I think a kit of Mike Renardson's Mosfet amplifier could draw the attention of diyers :
http://euraudio.dx.am/en/amp/MJR7/mjr7_en.htm
Yes, I mean the MJR7 is also a ultra low distortion amplifier and simpler than my LDA. Several people redesigned the Mike's original PCB already, so whoever wants an MJR7 PCB, could contact some of the persons who have a finished and well tested MJR7 PCB design, perhaps they'd share the PCB Gerber files. Then need to order components.
Presently I don't sell other kits, just the LDAs.
Presently I don't sell other kits, just the LDAs.
Still 10 mono LDA17 PCB's left for sale at non-profit price. There are detailed online assembly instructions available, and you can always write me an e-mail to ask if something's not clear.