Hey guys, a gradual lack of bass in my system. Could this be the valves aging ?
The four power tubes I replaced last year, but not touched the 6N1 pre and buffer ones in five or so years.
Any ideas pls as I don't have any valves I can swop and test with.
Amp: Yaqin MC-10L
Thanks
The four power tubes I replaced last year, but not touched the 6N1 pre and buffer ones in five or so years.
Any ideas pls as I don't have any valves I can swop and test with.
Amp: Yaqin MC-10L
Thanks
Hi Barbieboy,
Unlikely bad coupling caps unless they aren't rated for a high voltage. It is more likely that the tubes may possibly be getting weak, and that would also be accompanied with poor sound quality. I haven't got a schematic for that, so I can only talk in general terms. Sorry.
To help us out, is this an old amplifier, or is it recent manufacture? If it's an old amplifier, have you replaced the coupling capacitors yet?
-Chris
Unlikely bad coupling caps unless they aren't rated for a high voltage. It is more likely that the tubes may possibly be getting weak, and that would also be accompanied with poor sound quality. I haven't got a schematic for that, so I can only talk in general terms. Sorry.
To help us out, is this an old amplifier, or is it recent manufacture? If it's an old amplifier, have you replaced the coupling capacitors yet?
-Chris
Thanks guys,
The amp is around six years old from new. All caps replaced with ClarityCaps and Japanese resisters. Also upgraded the Cathode Resisters at each EL34 base.
No degrading of sound quality, just lack of bass which use to be plentiful 🙄
The amp is around six years old from new. All caps replaced with ClarityCaps and Japanese resisters. Also upgraded the Cathode Resisters at each EL34 base.
No degrading of sound quality, just lack of bass which use to be plentiful 🙄
Hi Barbieboy,
So that amplifier is new manufacture then. Age related problems will not be your problem.
Did this issue start after you did the "upgrades"? If it has capacitors from cathode to ground, you should also check those.
-Chris
So that amplifier is new manufacture then. Age related problems will not be your problem.
Did this issue start after you did the "upgrades"? If it has capacitors from cathode to ground, you should also check those.
-Chris
Have you checked your loudspeakers? Just a thought as I had a customer with a Quad 22 and poor bass. The cambric surround on the speakers were splitting.
Hi Barbieboy,
At this point you need to actually measure the output some way. You have to run a tone and measure the output to find out where it is really rolling off. Only after then can you look for problems. Otherwise, you won't know whether to look at the speaker (could have a swelled voice coil) or the amplifier. I can't see any common faults in an amplifier that is that new. Even your changes worked for a year before trouble showed up.
One possibility. I can't see the inside of the chassis,so this is a guess more than anything else. is it at all possible that a solder connection has become disconnected? Using your eyeballs is a first step in troubleshooting a problem. Solder joints certainly can fail after a year. Do you take this amp on the road?
-Chris
At this point you need to actually measure the output some way. You have to run a tone and measure the output to find out where it is really rolling off. Only after then can you look for problems. Otherwise, you won't know whether to look at the speaker (could have a swelled voice coil) or the amplifier. I can't see any common faults in an amplifier that is that new. Even your changes worked for a year before trouble showed up.
One possibility. I can't see the inside of the chassis,so this is a guess more than anything else. is it at all possible that a solder connection has become disconnected? Using your eyeballs is a first step in troubleshooting a problem. Solder joints certainly can fail after a year. Do you take this amp on the road?
-Chris
One easy thing before you start big efforts:Check the idle currents, are they equal? DC-unsymmetry in the output transformer leads to at least partial saturation or will diminish the low frequency behaviour.
Good hunting!
Good hunting!
Thanks guys,
Just had a neighbour pop in and he cranked the volume up higher than I normally do and said "you see, there is bass there". But I don't want to listen that loud, he thinks the problem is the amp is not powerful enough to produce low volume bass (52WPC into 4ohm speakers).
Ok he has a point, but this does not explain why it sounded nice before !
Just had a neighbour pop in and he cranked the volume up higher than I normally do and said "you see, there is bass there". But I don't want to listen that loud, he thinks the problem is the amp is not powerful enough to produce low volume bass (52WPC into 4ohm speakers).
Ok he has a point, but this does not explain why it sounded nice before !
If problem is in both channels, check PSU. Maybe +U is very low...? PSU doesn't have energy for bass...?
Start from rectifier and all el. caps.
Start from rectifier and all el. caps.
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If you have a multimeter, and a way to generate tones, like Audacity, you can measure at the speaker connector, with speakers connected.
Hi Barbieboy,
-Chris
Nope, that isn't reasonable. I have a 35 wpc amplifier that drives speakers with low bass notes no problem. If you are playing at low volume, you may need to engage loudness, or turn the bass up a little. Your amplifier should deliver the same power to speakers of 8 or 4 ohms if you are using the proper taps.
-Chris
Thanks guys for all the tips, speaker surrounds are fine, tried another set of speakers, same result, but good point.
Its looking like the pre / buffer 6N1 valves need replacing. Should I go for VOSKHOD ROCKET TUBEs ?
Its looking like the pre / buffer 6N1 valves need replacing. Should I go for VOSKHOD ROCKET TUBEs ?
Hi Barbieboy,
I'm not familiar with those tubes. Normally you would go with a known good brand. Anything from the Reflector factory, or New Sensor in New York would be a good bet.
-Chris
I'm not familiar with those tubes. Normally you would go with a known good brand. Anything from the Reflector factory, or New Sensor in New York would be a good bet.
-Chris
[1] Make a passive bass-boost circuit. One easy solution if all the rest of the circuit is OK.
[2] If both channels are the same, then it is quite unlikely that there's something systematic going wrong with the amplifier.
[3] How old are you? One of the things that begins to decline less obviously with age is bass ear response. We all know about 'failing treble'. But bass goes too…
[4] Is there a preamp between all your sources and the amplifier? Could easily be something within that, not the final amp.
[5] TRY YOUR CDs on another system, with different 'everything'. Play it at the volume level you like. Is there bass? If so, … then yah… something about your system might be amiss. If not… ears… age… expectations… false memories…
[6] Back in the "old days" one had stereos with 'tone controls'. They're pretty good at boosting bass, if that's what you like. Too bad they're near-gone these days. Just saying...
GoatGuy
[2] If both channels are the same, then it is quite unlikely that there's something systematic going wrong with the amplifier.
[3] How old are you? One of the things that begins to decline less obviously with age is bass ear response. We all know about 'failing treble'. But bass goes too…
[4] Is there a preamp between all your sources and the amplifier? Could easily be something within that, not the final amp.
[5] TRY YOUR CDs on another system, with different 'everything'. Play it at the volume level you like. Is there bass? If so, … then yah… something about your system might be amiss. If not… ears… age… expectations… false memories…
[6] Back in the "old days" one had stereos with 'tone controls'. They're pretty good at boosting bass, if that's what you like. Too bad they're near-gone these days. Just saying...
GoatGuy
Hi Goaty,
[1] don't know how to make one.
[3] 56 and the very same thing went through my mind, and didn't know that...
[4] No preamp, laptop, J.River, Asio, into usb Dac, into amp.
[5] Have no other system, but changed the speakers, made no difference. Wish I had another amp to play with.
[6] Could play with the EQ in j.river. OMG going back to tone controls in old age ? :/
[1] don't know how to make one.
[3] 56 and the very same thing went through my mind, and didn't know that...
[4] No preamp, laptop, J.River, Asio, into usb Dac, into amp.
[5] Have no other system, but changed the speakers, made no difference. Wish I had another amp to play with.
[6] Could play with the EQ in j.river. OMG going back to tone controls in old age ? :/
Hi Chris, they ship from Russia:
6N1P MATCHED PAIR 6922 6DJ8 ECC88 7308 VOSKHOD ROCKET TUBE XII-84 2PCS | eBay
Hi Barbieboy,
Go ahead and give them a try. Beats China on average.
Not bad going for an old guy! I'm the same age. We gotta stick together!
-Chris
Go ahead and give them a try. Beats China on average.
Not bad going for an old guy! I'm the same age. We gotta stick together!
-Chris
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