I got this 94 Linn Majik-I that I plan to use as a preamp with a lk100 currently shipping to me. It has never been serviced as far as I can tell. No visibly leaking capacitors. Dc at speaker terminals below 35mv.
I tested it with my speakers and the balance is off by quite a bit. Right channel is weak and a bit muddy.
Here's the interesting part though.
If I switch the rca, or the speaker cables, the problem switch from one side to the other. Im guessing something is wrong on the right signal path. Considering the age of this thing, I think the culprit could be a bad capacitor along the signal path. Source and cable issue have been ruled out.
Having it looked at, and professionally serviced would cost more than I paid for the amp. So I keep this option as a last resort.
I don't want to use the shotgun approach to this, but theres only a handful of capacitors per channel (all in stock on digikey) and at this point I just need a working amp.
Would I be crazy to give the recapping job a shot?
Anything else could be a high probability issue you think?
I tested it with my speakers and the balance is off by quite a bit. Right channel is weak and a bit muddy.
Here's the interesting part though.
If I switch the rca, or the speaker cables, the problem switch from one side to the other. Im guessing something is wrong on the right signal path. Considering the age of this thing, I think the culprit could be a bad capacitor along the signal path. Source and cable issue have been ruled out.
Having it looked at, and professionally serviced would cost more than I paid for the amp. So I keep this option as a last resort.
I don't want to use the shotgun approach to this, but theres only a handful of capacitors per channel (all in stock on digikey) and at this point I just need a working amp.
Would I be crazy to give the recapping job a shot?
Anything else could be a high probability issue you think?
Spray any switches first, and reflow the joints.
Use for a few days to reform caps, though at this age they might have gone weak.
A cap leaking to earth is a possible cause for your problem.
Do replacement after a week of use.
And be clear, RCA are input and speaker are output, problem should not happen both sides when cables swapped.
Check your source with headphones or another unit, to rule that out.
Use for a few days to reform caps, though at this age they might have gone weak.
A cap leaking to earth is a possible cause for your problem.
Do replacement after a week of use.
And be clear, RCA are input and speaker are output, problem should not happen both sides when cables swapped.
Check your source with headphones or another unit, to rule that out.
So I already did a deoxit job on everything that could benefit from it. I tested the source with another amp to rule it out. I didnt reflow the joints but Ill try that, can't hurt!
Update: I tried a different DAC and balance is good. Im now officially confused as hell. The Rega DAC-R is balanced with the Rega Brio but not with the Linn. The Linn is not balanced with the Rega DAC-R but is balanced with a cheap Grace SDAC. Output voltages at the rca are equal on the Brio DAC-R. I'd like to underline that the imbalance is not subjective, its quite significant.
Guess I should invest in a new dac? (Grace Sdac doesn't have the optical input I need)
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Eh? If you switched the RCA leads (assuming these leads are to your only signal source) and the sound fault shifted from one channel to the other, then surely the fault is before the amplifier. That is, it's either in your leads or the source. Find another pair of RCA lead(s) or test those you are currently using for end-to-end continuity. i.e. both pin to pin and ground shield to ground shield and also for a short between them ) with a multimeter or whatever you have for the purpose, before taking drastic measures.
I tried with different cables and the issue is the same. No shorts in the cables, and voltage is equal on both ends.
Why would the dac be problematic with one amp and not the other is what makes me confused.
The evidence that you can swap the fault channel with the input leads does point to it being related to only the one DAC channel output. If in doubt, surely you have or can borrow another input source such as a tuner, CD/MP3 player, PC sound output etc. to verify that both stereo channels will play simultaneously with other sources and the amplifier works fine or otherwise. As it's an older unit, you don't know what problems have developed over 25 odd years and it's likely to have been tinkered with, too. That makes a lot of things difficult to follow because you have to analyse the changes and deal with faults as they emerge so it gets a little complex and time consuming.
Without knowing the hows or whys, we could probably say this is a problem with the Rega DAC and its ability to drive enough current into both amplifier inputs, if there are no other obvious issues. I'd even check for DC on its outputs just to be certain it's OK to use.
Without knowing the hows or whys, we could probably say this is a problem with the Rega DAC and its ability to drive enough current into both amplifier inputs, if there are no other obvious issues. I'd even check for DC on its outputs just to be certain it's OK to use.
no DC coming off the rega dac. dc coming off the amp is not perfect but seems ok to use (one side around 30mv, the other around 19mv).
tried the amp with another dac and worked fine. Will try the Rega dac with usb instead of optical to see if anything changes.
What could explain that the dac works fine with the rega brio and not the linn?
Low input impedance, possibly. That is to say, the load on the DAC which could be too great for it to sustain a linear output. So it works acceptably with regular 47k, high level inputs but gets flattened by low impedance of say, 600Ω or even lower impedance inputs that are often used for microphones and pro. audio to reduce noise susceptibility. Alternatively, The Rega DAC may be in need of maintenance (caps usually) since it may work adequately as it has, but this load just tips it over the edge.
Majik's service manual spec. is 10kΩ for CD/Tuner/Tape/Aux. inputs which should be fine but you don't know what the status is in a used piece of gear. BTW, I don't think there will be any change with DAC input type. It's the output that's the problem as far as I can tell.
Majik's service manual spec. is 10kΩ for CD/Tuner/Tape/Aux. inputs which should be fine but you don't know what the status is in a used piece of gear. BTW, I don't think there will be any change with DAC input type. It's the output that's the problem as far as I can tell.
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i will do some more testing tonight. thank you very much for your feedback! I will let you know what comes of it.
What is most likely to happen is i will invest in a modern streamer that has a decent internal DAC such as the node by bluesound. I need a streamer anyway. This way, i hopefully should be able to listen to some tunes while i try to figure this DAC out. I also found that the Rega Brio-R has a right channel issue with a snap or click sound can be heard on the right channel when there is a significant load (bass hit in electronic music or similar demanding notes), which ill try to sort out as well. the rega dac and brio are great little pieces of kit, would be a shame not to find a way to use them.
What is most likely to happen is i will invest in a modern streamer that has a decent internal DAC such as the node by bluesound. I need a streamer anyway. This way, i hopefully should be able to listen to some tunes while i try to figure this DAC out. I also found that the Rega Brio-R has a right channel issue with a snap or click sound can be heard on the right channel when there is a significant load (bass hit in electronic music or similar demanding notes), which ill try to sort out as well. the rega dac and brio are great little pieces of kit, would be a shame not to find a way to use them.
I tool the voltage at the speaker outputs of the two amps and two dacs on a 60hz sine wave tone.
Here's what I found:
Dac-r + brio-r :
Left: 2.88v
Right: 1.99v
Difference: -0.89v / ~ -31%
Grace + brio-r
Left 2.88v
Right : 2.80v
Difference: -0.08v / ~ -2.7%
Grace + linn
Left: 2.90v
Right: 2.89v
Difference: -0.01v / ~ 0.3%
Dac-r + linn:
Left: 2.84v
Right: 0.94v
Difference: -1.9v / ~ -67%
And here is the dc offset I measured without load:
Linn:
Left: -29mv
Right: -17mv
Brio: nothing to report really
Looks like a bad dac, but why the difference is twice as big on the linn is beyond me.
I assume the reason I didn't really notice a balance issue on the brio is because an issue with it prevents me from driving it up too high without clicks and pops in right speaker output and my room placement being asymmetric at the time probably masked some of it.
I ordered a new streamer/dac. Hopefully ill have better success with it. Worst case scenario im back to square one, but with a cool first streamer I wanted.
I'd love your toughts on the results of the measurements I took in the meantime! Also since I read that the preamp section is spearate from the amp section on the linn, I tried to use it as a preamp with another amp, no changes, issue persists.
Here's what I found:
Dac-r + brio-r :
Left: 2.88v
Right: 1.99v
Difference: -0.89v / ~ -31%
Grace + brio-r
Left 2.88v
Right : 2.80v
Difference: -0.08v / ~ -2.7%
Grace + linn
Left: 2.90v
Right: 2.89v
Difference: -0.01v / ~ 0.3%
Dac-r + linn:
Left: 2.84v
Right: 0.94v
Difference: -1.9v / ~ -67%
And here is the dc offset I measured without load:
Linn:
Left: -29mv
Right: -17mv
Brio: nothing to report really
Looks like a bad dac, but why the difference is twice as big on the linn is beyond me.
I assume the reason I didn't really notice a balance issue on the brio is because an issue with it prevents me from driving it up too high without clicks and pops in right speaker output and my room placement being asymmetric at the time probably masked some of it.
I ordered a new streamer/dac. Hopefully ill have better success with it. Worst case scenario im back to square one, but with a cool first streamer I wanted.
I'd love your toughts on the results of the measurements I took in the meantime! Also since I read that the preamp section is spearate from the amp section on the linn, I tried to use it as a preamp with another amp, no changes, issue persists.
The difference in loaded output voltage from either channel of the DAC-R compared to the Grace is enough to tell you that the DAC-R is sick whilst there's no significant problem with the Grace unit. It may not actually be much of problem to repair but you would need at least the schematic to guide you, assuming you or your repairer also knew what to look for. That's the hard part.
At least now I know what is defective. Ill try the Node this weekend hopefully. Fingers crossed that the lk100 I have coming is in good shape.
IMO, a piece of cake to repair in that case (no schematic necessary).
Trace the signal backwards until you find the culprit.
It can't be very far back at all and may be even be a contact problem (connector, relay, etc.)
Not sure how to diagnose some of the components in it. I might pay for a checkup and see what I do then.