Overly bright set up: audiolab 8000a with mission 751

'm kind of new in the audio game. I recently installed my first proper set up: an Audiolab 8000a with Mission 751's. I play music through spotify premium (yes, I know) with a V-dac II connected to my Macbook. I mostly listen to alternative pop/rock.
I found the whole set up to be overly bright and after a short while of listening very fatiguing and even causing slight headache. Now I'm looking to replace one link in about the same price class to reach a warmer sound, I'd say my budget is around $400 and I mostly buy second hand. I do prefer a set up that doesn't color the music to much and is very detailed. That's why I settled on this set up in the first place, but it ended up being way to bright for comfortable listening.
I could replace the audiolab 8000a with for example a Nad c350
I could replace the Mission's for something warmer like a Dynaudio 40.
Or I could replace the V-dac II for example an Arcam Irdac, but I guess that will make the least difference.
Which peace of gear would you recommend keeping and which one would you recommend replacing? And with what? Any advice would be much appreciated.
 

Ian Finch

Member
Paid Member
2010-04-11 4:22 am
Coffs Harbour, NSW
As a choice of consumer products question, you'd do better asking that on a more appropriate forum. If you wanted to ask how to identify and fix a genuine fault, and that's what it seems like, there are several pros in the DIY community here who likely can help.

As a first step, I'd be looking for a different DAC and/or audio source to that in the Macbook/V-DAC. You don't have to buy anything if a friend has a system with standard audio sources like a disc player, their own USB DAC, Streamer Receiver, Tuner etc. that should be compatible with the amplifier's inputs. Use the CD input, since I expect that has the highest input level tolerance before clipping and producing harsh sound anyway.

The 8000A belongs to era when input sensitivity was higher and thus more susceptible to overload on some inputs. The input sensitivity spec. is only 100mV for all line levels so you can see a potential problem already - compared to today's digital sources of 1-2V peak output.

Use a different source and tell us if the sound is still harsh and fatiguing.
 
Trust me,-) The 8000a is an ugly thing. Causa (I repeat myself, again and agin and again)-: It is a multistage-complementary-parts-pp. With complementary-psu. With - I remember right? - a channel separated psu. In addition: ugly solder joints, ugly parts and more. You could try for years, but never ever you will get a clean tone, get music, get satisfaction. Use for boil water or drive jalousies, as all the other "state of the art" complementary-parts-pp amps should do.
Build for your mission a little se. As example.
 

Ian Finch

Member
Paid Member
2010-04-11 4:22 am
Coffs Harbour, NSW
I interpret the answer to mean the Macbook's audio output is lower level than the V-DAC, but easier on the ear. I guess you still have enough output to get the volume you expect, albeit at a higher volume control position. This would support it being a case of overdriving the input. A relatively simple way to fix it so you could use your external DAC, is by inserting a fixed or variable attenuator at the input of the amplifier and trying your V-DAC again with that attenuation. A fixed L-pad of 2 resistors or a potentimeter could be wired to do it variably for a wide range of attenuation.

Below is what simple attenuators look like and you could start by using an L-pad type and halving the signal amplitude or 6dB of attenuation with equal resistors of 10k, then try roughly quartering to about 12 db with R1 4.7k and R2 15k. Any film type resistors of 1/4 Watt rating will do fine for this.
[IMGDEAD]http://www.electronics-tutorials.ws/attenuators/attn8.gif?81223b[/IMGDEAD]

To use a pot, the voltage divider type illustration is adopted, where the pot resistance is the total of R1+R2 and the pot. wiper is represented by their junction. If R1 and R2 were the same 10k, then the pot is 20k or thereabouts - not critical. Then add another resistor of 10k (not shown) from the junction, or rather the pot. wiper, to the output. A 22k Log. taper pot would be suitable for this. e.g Omeg 22k Ω Log Dual-Gang Potentiometer | Maplin

Try either and see how easy it is to experiment for best sound without great expense, though it's stereo, so you need two attenuators or a dual pot and you'll also need 2 pair of cheap RCA sockets to adapt the attenuator to the DAC output and to the amplifier input with male/male RCA leads or if you have only a short distance, short insulated wires to RCA plugs will be fine. To avoid shorts, use inexpensive insulated connectors, not massive metal clad Hifi jewelry.
The full tutorial article is here: L-pad Attenuator Tutorial for Passive Attenuators
 
Last edited:
I would first address the issue to the compressed music stream.
It happens to me either: the first 1/2 hour it's ok, then I ask to myself " Why ? Whyyy ? Whyyyyyyy ??"
Low power might be a solution: 5 W amplifiers and inexpensive speakers from old radios, Tvs, might give a good clean sound but don't energize the room ( and the brain) too much.:eek:
 

Ian Finch

Member
Paid Member
2010-04-11 4:22 am
Coffs Harbour, NSW
I would first address the issue to the compressed music stream....
Well, the OP is happy with the Macbook DAC but not with the V-DAC output, compared using headphones. It seems to me there is either a different level or low-pass filtering going on there with the Macbook. Assuming of course, the VDAC and the Amplifier are in good condition and haven't previously been tinkered with. With so many wannabe modders out there, there are few old audio devices that haven't been already been screwed up :(