Help with Aikido Preamp+class d amp

dine1967 · 19th October 2010, 05:49 PM

I have an aikido preamp running on 24v with ecc86 tubes. The front of the preamp has a 10k r2r attenuator and the preamp feeds into a class d amp(CDA254). The amp has an input impedance of 7K and demands that the preamp should have an output impedance of less than 600 ohms. The problem I am having is selecting the output cap of the aikido. Based on the calculations, for 5Hz cutoff, I need a 4.5uf cap (1/159155/r/f). When I used a 4.7uf cap (blackgate N), the sound was thin. I replaced it with a 10uf cap and Iam getting bloated bass (kind of slow and high frequencies attenuated). There is something wrong somewhere either with my selection of capacitor or probably the choice of attenuator. I use to run a class AB amp before and it sounded great with 4.7uf cap. I would greatly appreciate if someone can help me out.
Thanks,
Dinesh

19th October 2010, 05:49 PM	#1
dine1967 diyAudio Member Join Date: Jan 2003 Location: NJ	Help with Aikido Preamp+class d amp I have an aikido preamp running on 24v with ecc86 tubes. The front of the preamp has a 10k r2r attenuator and the preamp feeds into a class d amp(CDA254). The amp has an input impedance of 7K and demands that the preamp should have an output impedance of less than 600 ohms. The problem I am having is selecting the output cap of the aikido. Based on the calculations, for 5Hz cutoff, I need a 4.5uf cap (1/159155/r/f). When I used a 4.7uf cap (blackgate N), the sound was thin. I replaced it with a 10uf cap and Iam getting bloated bass (kind of slow and high frequencies attenuated). There is something wrong somewhere either with my selection of capacitor or probably the choice of attenuator. I use to run a class AB amp before and it sounded great with 4.7uf cap. I would greatly appreciate if someone can help me out. Thanks, Dinesh

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Smallest Class A Preamp/Headphone Amp Design?	m0b1liz3	Headphone Systems	20	19th June 2008 11:19 PM
start-up sequence of Aikido preamp / SS power amp	cbutterworth	Tubes / Valves	5	7th May 2007 12:29 PM
Aikido Preamp	Bengali	Tubes / Valves	21	12th November 2006 03:19 PM
Aikido + class D in the output stage	jmartins	Tubes / Valves	2	6th June 2006 08:51 PM
aikido + class D in the output stage	jmartins	Class D	0	6th June 2006 06:21 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)