Hi, can anybody confirm how to work out power output of a valve amp? I bought a Chinese menygue mini, from a seller known as tubestein, via eBay late last year. The same amp is now being sold as a meng x3 12w version by seller not a 24w. The amp utilises 2 x el34b tubes an 2x6n2tubes, I found no earth to chassis, which has been added, but when warmed up there is a very low level hum from what looks like the main(nearest to front of unit) transformer?
Can anyone confirm the power op from this amp and any mods to rectify the hum? Being a newbie to the design of these amps and a reasonable knowledge of electrics( not electronics), I'm reluctant to play around inside without damaging the item, to note I have tightened up the transformer mountings and checked all the solder joints, but have found nothing obvious?
Any help greatly appreciated,
Tom(uk)
Can anyone confirm the power op from this amp and any mods to rectify the hum? Being a newbie to the design of these amps and a reasonable knowledge of electrics( not electronics), I'm reluctant to play around inside without damaging the item, to note I have tightened up the transformer mountings and checked all the solder joints, but have found nothing obvious?
Any help greatly appreciated,
Tom(uk)
I'm not familiar with that unit. Do you have some schematic? when you say 2xEL34, it's 2 per channel (4 for stereo amp) or one each channel?
Hi, there are 4 valves in total, an el34b and a smaller item marked on chassis where tube enters marked 6n2, I assume 2 for each channel. The seller did not supply a schematic and I would not have knowledge to draw one up.
I can send a link/ pics later as I am at work at moment, and posting messages via my iPhone. If you are at a pc,try eBay and search for meng x3 el34b, the seller is in china and called tubestein. The amp has 3 trannys with 2 el34b valves in front of transformer and 2 6n2's ? In front of the el34b's
Thanks
Tom
I can send a link/ pics later as I am at work at moment, and posting messages via my iPhone. If you are at a pc,try eBay and search for meng x3 el34b, the seller is in china and called tubestein. The amp has 3 trannys with 2 el34b valves in front of transformer and 2 6n2's ? In front of the el34b's
Thanks
Tom
I saw the pics and it cannot be a push-pull design using two EL34 for a sterreo amp. It must be a single-ended, and 12W might be the most you can squeze out of it (maybe less).
If the humm is mechanical (vibration from the power transformer) you can check if the potting of the transformer is filled with epoxy or similar or if it is emplty (the transformer just lays there with air around).
If humm comes from the amp (via loudspeakers), as it is a SE, I would gess the power supply is lacking on filtering.
If the humm is mechanical (vibration from the power transformer) you can check if the potting of the transformer is filled with epoxy or similar or if it is emplty (the transformer just lays there with air around).
If humm comes from the amp (via loudspeakers), as it is a SE, I would gess the power supply is lacking on filtering.
Hi, thanks for reply, sure it was advertised as p/p design as for the money approx£110, a single ended would be far more expensive?
As I said, I can post a layout of the pcb later, also,I'm sure from memory the trannys have a beige coloured paper bound around them.
How would they be filtered and what would need to be altered to correct the hum?
As I said, I can post a layout of the pcb later, also,I'm sure from memory the trannys have a beige coloured paper bound around them.
How would they be filtered and what would need to be altered to correct the hum?
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