kevin gilmore Posted January 18, 2015 Author Report Posted January 18, 2015 for a 10k pot, the series resistors should be 10k, and then calculate the other resistor for the attenuation you need
meeskees Posted January 18, 2015 Report Posted January 18, 2015 Sorry, I feel a bit stupid, but I don't know how to calculate. For the online calculators you need to know the output impedance.For a -10dB what value will suit?
Laowei Posted January 18, 2015 Report Posted January 18, 2015 (edited) http://www.uneeda-audio.com/pads/ Edited January 18, 2015 by Laowei
meeskees Posted January 18, 2015 Report Posted January 18, 2015 Thanks Laowei, I will give it a try, but first I have to study it.
luvdunhill Posted January 18, 2015 Report Posted January 18, 2015 Just use digital domain attenuation on the DAC.
meeskees Posted January 18, 2015 Report Posted January 18, 2015 Just use digital domain attenuation on the DAC. Don't know how to do this with the Gungnir . I am not sure about the calculations. With the 10k series risistors I calculated for -10dB 9.25k for the parallel resistor. Are these a reasonable values?
HemiSam Posted January 18, 2015 Report Posted January 18, 2015 Just use digital domain attenuation on the DAC. Exactly my thought. HS
Laowei Posted January 18, 2015 Report Posted January 18, 2015 Digital attenuation leaves artifacts, even at 32bit depth and 64bit computation. I too was a sceptic before I heard with SR-009. http://www.parts-express.com/in-line-xlr-attenuator-pad-10db--240-412
meeskees Posted January 19, 2015 Report Posted January 19, 2015 Thanks Laowei,now I understand what Kevin meant with the Neutrik connector. The problem is I don't have enough space behind my amp.I already use angled connectors. Besides I think it is a bit overkill.I only need 6 resistors to attenuate the signal. I have done some new calculations: line input 10k, attenuation 10dB, R1 & R2 2700 ohms, R3 3300 ohms.
HemiSam Posted January 19, 2015 Report Posted January 19, 2015 The DAC is a Schiit Gungnir.According the specs it is maximum output XLR 4.0V RMS This has been an interesting exchange. I checked my Beresford Caiman MkII and it puts out 2.0Vrms so I think I'll be in a better place with my KGST. HS 1
Laowei Posted January 19, 2015 Report Posted January 19, 2015 (edited) I'm using a Gungnir in 4V balanced output too. It's truely a balanced circuit directly from the differential DACs, not an afterthought. With a Gungnir, one could always easily go to SE output at 2V and get a -6dB attenuation. The 50K Alpha pot in my KGST is at about 8:30-9:00 for a realistic volume level. I just bought a 4 gang Alps RK50 from Justin to try out on my next build. I may try some attenuation before it with some Vishay TX2575 resistors to give a more useful range of adjustment. Edited January 19, 2015 by Laowei 1
meeskees Posted January 20, 2015 Report Posted January 20, 2015 After work I have done some soldering. This site gives lot of information http://www.sengpielaudio.com/calculator-voltagedivider.htm. I made an attenuator with resistors I had by hand.I used circuit B .With two 10k seriesrisistors and 5.6 parallel. The attenuation should be 11.5dB. I think it can even a bit more. 12.00 o'clock is now OK with classical music, but much too loud with modern pop music.Older pop music is not so loud.
luvdunhill Posted January 20, 2015 Report Posted January 20, 2015 This is DIY. The other stuff is just kit building I tell people if you aren't constantly using ohms law when doing a DIY project, it's not DIY. Ok, I don't tell people that, but just told you guys here and now 1
nikongod Posted January 20, 2015 Report Posted January 20, 2015 Circuit B should show 1/2R2=R2*0.5 for each of the "R2" to ground, if it is to give the same attenuation as Circuit A.
meeskees Posted January 20, 2015 Report Posted January 20, 2015 The drawing is from DIY. There was a discussion which circuit is better.(B they say).I used the online calculator in the link.
nikongod Posted January 20, 2015 Report Posted January 20, 2015 I prefer A. B requires more parts=more part matching.
Laowei Posted January 20, 2015 Report Posted January 20, 2015 I prefer A too. Balanced input (opposite polarity signals) are referenced to each other, and ground is not referenced. 1
meeskees Posted January 21, 2015 Report Posted January 21, 2015 http://www.diyaudio.com/forums/analog-line-level/266052-passive-balanced-attenuator-between-pre-power.html
kevin gilmore Posted January 21, 2015 Author Report Posted January 21, 2015 that depends on whether the output is true balanced or ground referenced. true balanced may cause interesting dc level issues releated to common mode.
feraldi Posted January 26, 2015 Report Posted January 26, 2015 Greetings to the entire collective of Head-Case.org, this is my first post and I want to take this opportunity to introduce myself. I write to you from Spain. Long time ago I use headphones, but just three years I have serious devices, the same time that I am a member of the best forum headphones in my country. In fact I see some familiar faces here . I have academic background in electronics and electricity and have interest in DIY projects developed in this community, especially the electrostatic headphones amplifiers, in fact want to start building a KGST. I ask you to forgive my English, is very bad and I'm sure many will say stupid things, I hope not to bother too much with them. Also take this opportunity to thank Remolon for discover me this project, Jose for encouraging me to build and especially to Headinclouds for providing me purchase of the material. To all of them thank you very much friends. Nice to be here with you. Fernando 3
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now