usually there is a unused 240V socket behind the dryer in case the homeowner decide to use electric dryer.
Builder went cheap and only ran a gas line to the laundry room. If swapping the preamp tubes doesn't eliminate the hum, I may have to bite the bullet and lug my system over to a friend's place that has a 240V socket for their electric dryer.
I'm getting a separate preamp (Linear Tube Audio MicroZOTL Pre) for my LM-805IA for Christmas. Given that, does it still make sense for me to roll the two 6SN7 tubes on my Line Magnetic? I already swapped out the 6SL7 but I'm curious if those tubes will make that much of a difference now that I'm going to be running it in power amp mode. Any thoughts?
the only thing bypassed in preamp input is the volume control. the 6SL7/6SN7 are still in the signal path. so you should still upgrade the tubes.
UPDATE: I replaced all three preamp tubes and the hum coming from both speakers is still present. In fact, the hum worsened slightly after replacing the stock 6SL7. The level of hum was improved by adjusting the N.F.B. with 1 being the worst and 4 being the best but it's still audible when there is no ambient noise in the room.
Hello guys, Yesterday I had, without knowing, the bias in one tube setted over 120, around 130/135 may be, in my LM-508. The sound was a little bit harsh and there were a little unbalance in the soundstage, so I checked the bias and I found out the difference. After adjusting bias, I dont think is my imagination, but the sound got smoother and the soundstage recovered the balance. Did anyone of you had a similar experience? I understand the bias is set on the 300B tubes. Am I correct?
not surprising. going up to 135mA pushes the operating point of the 805 quite a bit away from the designed operating point. it can introduce distortion due to to operating closer to the rails, and as a result, produce the harsher sound and the dissimilar output will screw up the soundstage. the bias is set on the 300B but measured on the 805. the 300B and 805 are tightly locked together so any change in the 300B bias is directly reflected on the 805.
Question: Testing the amp on 240V power is not going to be possible, so I'm thinking of trying a Topaz 120/240 isolation transformer. There was a comment in this thread that the isolation transformer should be 1kW so as not to limit dynamics. The spec sheet for the LM-508IA states power consumption is 400W so this seems to be a lot of headroom. Would a 750W transformer be sufficient?
I know it's inconvenient to bring it elsewhere but buying more SUTs isn't the answer, IMHO. A $40 converter and some inconvenience will give you a definitive answer. Otherwise, it's purely guessing which could take much longer to determine the real cause of the problem. And, if you remember, in my case (and those of 2 other members), a specific cap imploded which affected other caps as well. In my case, two tubes became defective. Just my 2 cents but you should simply bring it to a tech to have the work done anyway since it'd be taking a chance regardless. If that addresses the issue, you killed two birds with one stone. If it isn't the cause, you fixed a problem which likely could have eventually occurred which will protect the amp in the future and you can resume troubleshooting afterwards. The tech should be able to test the amp at 240V anyway.
I've searched your thread on the capacitor issue but could not find a part number of the stock capacitor that was replaced. Do you happen to know the part number of the capacitor that failed and could you share the replacement part number of the capacitor you purchased? I've also searched but could not find a schematic for the 508IA. Is there a schematic available?
Hi I recently bought a new 508IA from an Ebay seller. Before buying I asked the seller about warranty and his answer was I will get a schematic of the Amp, get it fixed locally and will be re embraced (which I don't believe). After buying I asked for the schematic but the seller answered I will get it in an event of a failure or after 6 months. Sounds very strange to me...
Beware! There are fake Line Magnetic amps that are often sold on ebay. Line magnetic have a list of their authorised dealers on their website.... After sale If the seller is not an authorised dealer, get in touch with ebay and explain the situation. I'm sure they'll step in if you've been sold a fake.
No schematics are available online or elsewhere that I was able to find. Unfortunately, I'm unaware of the specific part number. It looks identical to the cap that is currently there with the exception of being rated for 500V and 105 degrees Celcius instead of the puny 85 the original cap could tolerate. I wish I could be more helpful but cap types confuse me to no end. If need be, I can ask my tech but I'm unsure if he'll specifically remember the part number of a cap he ordered a few months ago for one customer. There is no online schematic for this amp. Unless that person decides to map it out which would take hours and hours, you won't get a schematic. Even LM won't provide one. He is lying, sorry. eBay sellers do not need to provide warranty support, nor should they. But if there's a problem with the amp within a 3-month period (IIRC), you can contact the seller and return the amp if there's a problem for a full refund. Unless the amp is relatively new, the warranty period has already expired and in most cases, manufacturers will only honor the warranty to the original buyer anyway. Lastly, any promises about having it fixed locally and then being refunded aren't enforceable so you're taking a chance that he'll be true to his word. And it doesn't sound (from your description) like he would be trustworthy. That's incorrect. They don't exist. What does exist however, is LM amps from China being sold for cheaper than what they sell for over here. That is called the gray market and is perfectly legal but there's understandably zero warranty support from the manufacturer (and frankly, there shouldn't be any for those situations). The other possibility is an amp that has been modified, as was the case with one relatively recent thread. In that case, the store advertised the modifications so the buyer knew what he was getting from the get-go. Most of what is sold on eBay are from unauthorized sellers. For instance, if I sell the amp (or anything else on eBay), I'm not an authorized seller of anything. That's the nature of 2nd-hand products as well so no idea why you'd give that poor advice to him.
From Line Magnetic website.. Line Magnetic discovered that counterfeit versions of its products were offered for sale, notably on well-known auction websites. These counterfeit items may appear visually as very similar, but the components and the final sound reproduction is nothing like those delivered by original products. These counterfeit devices are not CE-compliant. Some components are not identical to those intended for the European market.
I'm quite aware of what their website says, thank you. LM fakes don't exist, period. Show me a single one, please. They do not exist. At all. Think about it for one moment. Why would anyone bother to make duplicate casings and create working compatible schematics, go through the trouble of sourcing cheaper replacement components, to create a fake LM unit when they sold probably just a few dozen? Firstly, that makes no time/money business ratio sense. Secondly, there are far more desirable and recognizable brand names to fake (like Apple). Thirdly, no fake has ever been shown by LM or anyone else online, ever. Fourthly, LM is using the word "counterfeit" to refer to models made for other markets such as the Chinese-market 508IA that I have running which is made with 240V transformers and is therefore incompatible with our 120V electrical lines. However, I simply had an electrician combine two 120V lines and everything works perfectly and has for many months. I realize you're trying to be helpful, but mentioning stuff that is simply untrue isn't helping anyone and is doing frankly a disservice to who you're actually trying to help.
If you buy your Line Magnetic amp from a country where there's no official dealer, like mine (Argentina), you should get an official dealer from China, at a very convenient price. The only problem is that in LM website all chinese dealers have their info in chinese, but you can get their pones and call them. From LM website I've got the phone of www.china-hifi-audio.com Yong, the seller on that website is very responsible. I bought my LM508 from him with out any problem. I also bought some tubes from him and once I've got a broken Psvane 805A-TII that he replaced right away. I only had to sent him back the broken one, wich cost me about USD 30. You also can Pay him with Paypal and get their buyer protection insurance.
100%, yes. I saved 3K buying a Chinese-market 508IA as opposed to buying a 120V version here. You think they're unaware a bunch of people are doing that? And you think they don't want to scare some into instead spending more for the North-America version? Fakes don't exist. They use words like "fake" and "counterfeit" to mean "outside of market".
In www.china-hifi-audio.com you can get your LM-508 at about 2k plus shipping (I guess about 300/400 USD) plus custom taxes. A true bargain.
