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Post by PinkFloyd on Feb 8, 2010 21:40:25 GMT
I am loving BOTH of these amps but, for me, at the moment, the Indeed has the slight edge sonically.... it throws the sound out of the head a bit more than the Bravo and overall the tone is more "thrummy" and euphonic.... it could be the Dale resistors that are giving it the edge, I don't know yet... I will have to let both amps fully burn in and get to know them a little bit better before I can say what effect different components have on the sound. It's clear to me, however, at this early stage, that BOTH amps are a phenomenal buy for the money and I will be keeping both of them (hopefully as "active amps" and not relegated to the amp "museum") I'll use one of them as a TV headphone amp and, possibly, the other as a desktop amp..... my main rig is pretty full at the moment (with the WAD HD-83 as my main amp) but I may be able to slot one of these in purely for "electro" duty (I just LOVE the way these amps present electro) I feel they struggle a bit ( not a lot, just a bit) with more complex arrangements so will use the HD-83 / V2 / WNA MKlll for more involved listening. I hope to find time soon to start valve rolling and will be knocking up a linear / regulated PSU which I'm SURE will take this amp into a third dimension  |
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Post by PinkFloyd on Feb 8, 2010 22:06:18 GMT
A closer look at the two amps: Indeed:  Bravo:  You will notice (from the arrows) that there is a cap missing on the indeed PCB. This is nothing to worry about. Bravo have obviously fitted a cap there in the hope that they can reduce the "pop" pulse when the amp is switched on but it doesn't do much good (if any!)...... I believe Indeed have solved the "pop" pulse in their G2 version of the amp (more on that later) and they omit the cap as it doesn't do anything really useful. Bravo employ little ceramic caps (as denoted by the arrows) Indeed employ a Philips film cap (the blue one) which they claim reduces the ESR of the 2200uF Nichicon cap which improves the charge/release time and improves high frequency response (sounds about right to me) I haven't checked the value of this cap yet but, from the size of the Philips cap, it's pretty small.... Fitting a bigger film cap here could be sonically advantageous, I'll experiment with a few different values...... obviously, considering the size of the PCB and the amp it's best to keep things "sensible" and aesthetically pleasing / inkeeping with the amp. Mick, I look forward to your developments re: the heatsinking and feet..... sounds VERY promising. Mike. |
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Post by MaN227 on Feb 9, 2010 7:11:17 GMT
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Post by Deleted on Feb 9, 2010 17:25:50 GMT
The Bravo certainly is delivering the goods. Even the K701 is delivering strong, punchy bass now the bias has been adjusted.
Mine was at just under 11v one side and 12.5 the other. Upping it has fattened the sound out and the K701 has really come to life.
I managed to tweak until both side came out at 16.44. After that, I thought that's it ........ no more. It's easy to get a bit OCD about it.
I'll give it another check tomorrow after I've run it today but the sound has taken off big time.
The bass is awesome on the HD681 now.
Ian
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Post by gomez on Feb 9, 2010 20:25:30 GMT
Well got the new valves today so promptly changed the valve switched on...........HHHHHIIIIIISSSSSSSSSSSSS B**T**d  Tried another switched on......HHHHSSSSSSSSSSSSSSSSS ####### ******** Looks like it's heading back to Hong Kong. Wouldn't you know it Chinese New Year oh joy nobody works again until the 22nd including their Post office  Gomez........ |
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Post by Deleted on Feb 9, 2010 20:44:18 GMT
Thats a bummer Paul, sorry to hear that, and Chinese New Year!!, hasn`t anybody told them yet, ITS GONE, its on the 1st of January!! Never mind these things happen, not the end of the World, just disappointing i think. Would you like to borrow mine while i`m away, i have the XCAN i can use when i get home, till you get a replacement, so no problems where i`m concerned.  Mick. |
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Post by Deleted on Feb 9, 2010 21:04:45 GMT
Thats a bummer Paul, sorry to hear that, Would you like to borrow mine while i`m away, i have the XCAN i can use when i get home, till you get a replacement, so no problems where i`m concerned. Mick. Nowt to do wi' me but that is what makes this forum the place it is. Nice one Mick. DaveK. |
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Post by gomez on Feb 9, 2010 21:23:26 GMT
Thats a bummer Paul, sorry to hear that, and Chinese New Year!!, hasn`t anybody told them yet, ITS GONE, its on the 1st of January!! Never mind these things happen, not the end of the World, just disappointing i think. Would you like to borrow mine while i`m away, i have the XCAN i can use when i get home, till you get a replacement, so no problems where i`m concerned. Mick. Mick You are really one in a Million mate  Really nice of you to offer. I think I may have a plan though I'll keep you posted  The New rings arrived today Absolutely Superb ( as usual ) I'll be putting them on in the morning Thanks. Paul.... |
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Post by PinkFloyd on Feb 9, 2010 23:21:12 GMT
Totally off topic but I have just seen pictures of the New Indeed "G2" version of the amp. I have promised Peter I will not publish it on the forum (and I won't) but I can say it looks very tasty indeed.
It will be released after the Chinese New Year and I hope to be able to give more info then.
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Post by clausdk on Feb 9, 2010 23:30:30 GMT
Well got the new valves today so promptly changed the valve switched on...........HHHHHIIIIIISSSSSSSSSSSSS B**T**d Tried another switched on......HHHHSSSSSSSSSSSSSSSSS ####### ******** Looks like it's heading back to Hong Kong. Wouldn't you know it Chinese New Year oh joy nobody works again until the 22nd including their Post office Gomez........ Sounds like someone is going to eat some kind of headwear.. BON APPETITRemember the pictures  |
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leo
Been here a while! 
Team wtf is it?
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Post by leo on Feb 10, 2010 0:10:20 GMT
Well got the new valves today so promptly changed the valve switched on...........HHHHHIIIIIISSSSSSSSSSSSS B**T**d Tried another switched on......HHHHSSSSSSSSSSSSSSSSS ####### ******** Looks like it's heading back to Hong Kong. Wouldn't you know it Chinese New Year oh joy nobody works again until the 22nd including their Post office Gomez........ Hiss on both channels? theres not a huge amount to go wrong on these tbh Shame you don't know anybody close who has one so you could try theirs just to be sure it is faulty and not normal/within spec. remember these are pretty high gain and its not the quietest of circuit It would be a pain if the replacement after all the waiting turned out to be no better, you may of course have a faulty one but its worth being sure before sending it back |
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Post by oohms on Feb 10, 2010 9:48:22 GMT
So my 12AU7 Bravo arrived today... Let it warm up for 20 minutes, plugged in my AD700's.. WOW! Very impressive! I particularly like its detailed bass, and otherwise the sound is good. (I need to use a better source than my laptop) This one also doesn't seem to pick up interference, even with the phone lying right next to it. But it is designed a bit differently from the ones you guys have. It doesn't have an adjustable resistor, the cathode is connected straight to ground, as well as some other small changes. I'll upload a schematic soon. Can somebody do me a huge favour and meaure the range of bias voltages you get by adjusting the pot? Mine seems to be biased at 12v by grounding the cathode. As far as modding these things, most of this amp (apart from the tube stage) is based off the Szekeres amp. gilmore2.chem.northwestern.edu/projects/showproj.php?file=szeke1_prj.htmThe Szekeres has been modded a lot, so we can use that as a start when modding the Indeed/Bravo. First thing i notice is that the Mosfets have an input capacitance of more than 500pF, where the Szekeres uses one of 200 or less. I will replace it with an IRF510 (135pF), and hopefully it will improve the frequency response a bit. If i am game (and have bigger heatsinks lying around) i think i will also increase the idle current for even more bass. When it comes to biasing, it is possible to insert a capacitor between the Anode and the 220 ohm gate resistor, and use 2 additional resistors to manually set the bias (from the Szekeres) but i might try and add a pot like the version everyone else seems to have, and bias it that way. |
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Post by Deleted on Feb 10, 2010 10:20:40 GMT
oohms
I asked this back in reply 199
SandyK
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Post by PinkFloyd on Feb 10, 2010 10:29:38 GMT
IRF510 are only 26p each.... I'll give them a go and see how they sound |
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Post by Deleted on Feb 10, 2010 10:40:01 GMT
IRF510 are only 26p each.... I'll give them a go and see how they sound Mike You could also try reducing the value of the 3K emitter resistors to say, 2.2Kohms, and readjusting the bias again. . Mind you, this is only a hunch. Alex |
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Post by PinkFloyd on Feb 10, 2010 10:43:24 GMT
IRF510 are only 26p each.... I'll give them a go and see how they sound Mike You could also try reducing the value of the 3K emitter resistors to say, 2.2Kohms, and readjusting the bias again. . Mind you, this is only a hunch. Alex Will give it a go Alex.... just ordered some IRF510 so will see how they go first. Nice little amps these Alex  |
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Post by Deleted on Feb 10, 2010 15:52:06 GMT
With a Russian 6h23 Valve fitted can get 10.4-22.3v left channel and 10.7- 23v right channel.
However when i had a Jan Phillips 6922 fitted i could only get as high as just over 15v on both channels, but full range was achievable with the original Valve(electro harmonix) fitted.
Hope this helps.
Mick.
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Post by PinkFloyd on Feb 13, 2010 20:48:06 GMT
Still waiting for the IRF510 to arrive (will be Monday now) but have been piddling about with the Bravo amp in the meantime: First off I removed that cruddy little ceramic capacitor (80nF) which is bypassing the 6800uF Rubycon electrolytic. To be honest guys, if you don't plan on replacing it with a better (higher capacity) film cap then just snip it off.... god only knows what they were thinking bypassing a large 6800uF cap with a "80nF" ceramic.....  I decided to replace it with a 3.3uF WIMA film cap:  I had a listen and the over all clarity of the amp had improved slightly so I decided to keep the Wima in place:  Next up I replaced the stock el cheapo phono sockets with equally "cheap" types but these appeared to have a better quality plating on them:   The other changes I had made previously were to fit 2 x 1000uF Panasonic FM and a Neutrik gold plated headphone jack:  Just awaiting the IRF510 now, have removed the stock mosfets so it's all ready for them to be fitted:  Whilst I had the heatsinks off I replaced the other small ceramic cap (which is supposed to stop the pop pulse but it doesn't) and replaced it with a 220nF el cheapo WIMA type.... this will have no effect on SQ:   I will report back once the IRF510's have been fitted. |
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Post by Deleted on Feb 14, 2010 10:39:30 GMT
Hi Mike,
Another naive numptie newbie question I'm afraid. I plan on getting an Indeed or Bravo amp once the dust has settled here on which is the best buy. I have a 2 x 25v TX which I bought to complete my semi-DIY GainClone kit. I don't think I shall be wanting to keep the GainClone so could I use the TX to feed the Indeed or Bravo amp?
Thanks for any advice.
Dave.
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Post by andy on Feb 14, 2010 19:30:33 GMT
Daft question, but would a GS PSU1 be man enough to power the bravo? i am finding that i dont really use my solo much at the moment as i prefer the bravo.
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Post by PinkFloyd on Feb 14, 2010 19:49:29 GMT
Daft question, but would a GS PSU1 be man enough to power the bravo? i am finding that i dont really use my solo much at the moment as i prefer the bravo. Nooooooo! You'd burn the arse out of the Graham Slee PSU1, it's only good for 200mA  |
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Post by PinkFloyd on Feb 14, 2010 19:50:58 GMT
Hi Mike, Another naive numptie newbie question I'm afraid. I plan on getting an Indeed or Bravo amp once the dust has settled here on which is the best buy. I have a 2 x 25v TX which I bought to complete my semi-DIY GainClone kit. I don't think I shall be wanting to keep the GainClone so could I use the TX to feed the Indeed or Bravo amp? Thanks for any advice. Dave. Hi Dave, Yes, of course you can use the 2 x 25V transformer.... what VA rating is it? Mike. |
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Post by PinkFloyd on Feb 14, 2010 21:06:41 GMT
You'll notice I removed my post offering to send out a small PSU to members.... the reason being the damn thing was running way too hot  I've been messing about today with one of my simple PCB's with an L7824 onboard.... all done on a block of wood until I am happy to house it in an enclosure... NOT safe if you have children or animals kicking about so please don't replicate this! I only have myself to electrocute so make a point of not licking it with my tongue "until" it's all safely housed in an enclosure  I found an old 60VA / 25V + 25V toroidal kicking about in a drawer so screwed it onto the block of wood.... connected up to the regulator board (L7824, bridge rectifier, Panasonic FM 2200uF, ELNA RE2J 1000uF, WIMA 3.3uF film caps....) and fired her up......  Sounded absolutely breathtaking, considering the simplicity, but the regulator was running a bit too hot for my liking..... soooo, I modified an old AMD CPU heatsink (drilled a hole in it ;D) and bolted the L7824 onto it:   You can pick these CPU heatsinks up for pennies on ebay and they really are kick arse coolers for regulators.... a little smear of thermal paste, a mama honker CPU heatsink and the regulator is now dissipating the heat beautifully Sound quality? PHENOMENAL! As I said in my previous thread (the one I deleted).... the difference is quite simply stunning. Where before there was a wall of music there are now seperate layers with each performer / instrument in it's own "space"..... This is a seriously good amp with the stock SMPS power supply but feed it with something a bit better, even one as simple as this, and, boy, you are in for a sonic treat I'll order up a nice enclosure and box this little PSU up (with the mama honking heatsink strapped onto the side of it  ) I feel it is worth it, I just don't want to go back to the SMPS now. |
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Post by Deleted on Feb 14, 2010 22:13:11 GMT
Hi Mike, Another naive numptie newbie question I'm afraid. I plan on getting an Indeed or Bravo amp once the dust has settled here on which is the best buy. I have a 2 x 25v TX which I bought to complete my semi-DIY GainClone kit. I don't think I shall be wanting to keep the GainClone so could I use the TX to feed the Indeed or Bravo amp? Thanks for any advice. Dave. Hi Dave, Yes, of course you can use the 2 x 25V transformer.... what VA rating is it? Mike. Hi Mike, Thanks for that. I believe the Va is 225 and, IIRC, this is the actual TX: uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=4225332Hope this helps you (to help me). Thanks for your help. |
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Post by PinkFloyd on Feb 14, 2010 23:18:56 GMT
Jesus.... 225VA is "Overkill" but there has never been anything wrong with overkill..... a 225VA will have better regulation than a 30VA (8% as opposed to 18%).... ALL GOOD STUFF..... go for it |
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;D . . . 
Tried another switched on......HHHHSSSSSSSSSSSSSSSSS ####### ******** 
Really nice of you to offer. I think I may have a plan though I'll keep you posted 
) I feel it is worth it, I just don't want to go back to the SMPS now.