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Post by Deleted on Oct 13, 2012 7:50:27 GMT
That's what's quite puzzling about this amp. It's in an open frame and so has air all around it. I dread to think what would happen if it was boxed up.
It also makes you wonder why any designer wouldn't take steps to draw the heat away since long term, it's a killer. I guess makers aren't concerned about long term. As long as it lasts about year, then that's fine. Mine averaged 6 months.
The Little Dot that I had went up like a firework. It can be very dangerous.
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Post by Deleted on Oct 13, 2012 8:19:15 GMT
Hi Ian Have a look at this photo showing how heat sources appear to be grouped fairly close together. A metal base plate with pillars bolted to the heatsinks above may have helped get rid of some more heat ? The main electrolytic capacitor looks like it may get pretty warm too ? Regards Alex Attachments:
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Post by Deleted on Oct 13, 2012 8:31:11 GMT
That was one of Franz mods in his guide, with the addition of attaching one pair hot devices directly to said base plate to dissipate more heat. We had a little buzz and some fun tinkering with these quirky amps but they aren't really worth the bother. A lesson learned on too good (ie cheap) to be true  Sent from my HTC One S using proboards |
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Post by Deleted on Oct 13, 2012 8:47:33 GMT
Hi Chris I think you may be right. Probably last just long enough to get through a short warranty period.  Regards Alex |
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Post by Deleted on Oct 13, 2012 11:35:21 GMT
Exactly what happened to all 4 of mine Alex. It is a bit disconcerting if you like the sound of the amp but the build just isn't right imo. Remember mine was nicknamed the Twin Towers because of two huge heatsinks. It still got hot although the heatsinks helped enormously. The same thing has perhaps crept over to Horizon too!! If you're a good DIYer, then it's no problem to replace a failing component but not for most. You are right, that capacitor also gets a bit warm. It's the biggest disadvantage to these amps and unfortunately, also an issue that many retailers don't worry about as long as it gets through a warranty period. The joys of valves eh? |
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Post by Zigis on Oct 20, 2012 12:11:10 GMT
What die most often in cheap amps? El. caps close to hot heatsink or something else?
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Post by Deleted on Oct 20, 2012 12:33:03 GMT
Zigis, we're talking about these cheap amps that have been selling like hot cakes with a valve. Sound is fine (rolled off top) but they tend to get so hot that something ends up fried on the board.
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Post by mscosta on Oct 27, 2012 23:52:14 GMT
hello I buy a muse v2 but the sound is  very bad much noise... I can upgrade my muse but I have some questions: i'il get this mods: 1: Add cathode caps 470uF/10V 2: Replace the 6,800uF/25V for a 4700uf/35V 3: Replace output caps for a 2200uf/25V 4: Replace IRF630 to IRL510 5: Replace LM317 to LM317AT ( 6: Feed heaters from own power supply I il use the tube electro harmonix 6922, what is the better tube roll current? my amp has a 4.5 ohms to the lm317 pin2 my headsphone has 32ohms the output resister 47ohms is work fine? i can change the 2n3906 to the bc560 low noise? improve the sound? change the 100nf output parallel caps for another value or eliminte? |
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Post by Deleted on Oct 28, 2012 0:28:21 GMT
Did it sound this bad with the same tube before you started modifications?
Unless you are very experienced, NEVER do a series of modifications without a listening test AFTER each change.
Now you are going to need to reverse a series of modifications to see which one caused the problem.If done correctly, the different type of LM317 can be ruled out.THe LM317AT is simply a closer tolerance and lower noise version.Replacing the constant current source transistor with a lower noise type would be a waste of time,
as the ultimate signal to noise ratio was decided by the decision to use valves in this design.
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Post by mscosta on Oct 28, 2012 16:12:45 GMT
sorry my bad english I'm portuguese  I did not do anything so far, I'll make these modifications when I get the parts, some parts is hards to find... the sound, has much noise |
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Post by Deleted on Oct 28, 2012 22:58:45 GMT
sorry my bad english I'm portuguese I did not do anything so far, I'll make these modifications when I get the parts, some parts is hards to find... the sound, has much noise If I were you, I would order a couple of high quality tested NOS valves before you do much else, then do mods one at a time after that. PinkFloyd (Mike ) sells good quality NOS tested valves at very competitive prices, Send him a PM by clicking on PinKFloyd where you see it in the forum. Regards Alex, P.S. Also try gently scraping the valve pins to get a nice clean surface and reinsert it again. |
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Post by Deleted on Oct 31, 2012 11:29:45 GMT
sorry my bad english I'm portuguese I did not do anything so far, I'll make these modifications when I get the parts, some parts is hards to find... the sound, has much noise I'm sorry Costa, the Muse version is particularly noisy. I had one sent for a review and it was awful.So bad, I chucked it away. I couldn't give that to anyone. The better ones are the Indeed and the G3. However, imo, they all have a very limited life due to the heat generated. Personally, I'd leave it. |
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Post by ruinevil on Nov 9, 2012 16:55:18 GMT
Yea... the was a background noise when I was using my Muse stock, which made it only usable between 9 and 11 O'clock. It mostly disappeared when I switched out the MOSFETs. I solder wicked as much of the old solder as I could.
The stock 6N11 is pretty crappy.
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Post by alejandro508 on Nov 22, 2016 0:31:49 GMT
Has anyone been able to experiment with throwing a 12BH7 in the Bravo V2? Any ideas as to whether or not it might work? I ask because I've heard that it's a much better tube than 12AU7s and that in some 12AU7 amps people successfully throw them in without issue.
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raa
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Post by raa on Mar 10, 2017 20:38:14 GMT
Hello all!! I am planning to buy one of the Bravo amps and would like to know which is best the V1 or V2. I am leaning toward the V1 since it has adjustable bias and have read it can run both 6922 and 12AU7 tubes with a simple change in bias settings. I am super new to all of this so your thoughts would be greatly appreciated. The business I will be purchasing from has both models in stock and they are on clearance so please advise.-Rusty
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Post by alistair72 on Jun 22, 2019 23:21:27 GMT
Similar to the above Q, can you get the indeed amp? I can’t find one on the bay. I have found a bravo on amazon.
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Post by alistair72 on Jun 23, 2019 8:29:04 GMT
Found it!
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nando
Been here a while! 
The Frying Dutchman
Always look on the bright side of life
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Post by nando on Jun 25, 2019 7:00:57 GMT
Please let us know what you think of it, if you will mod the hell out of it and some photo’s are very welcome.
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very bad much noise...
