oldson
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Post by oldson on May 4, 2013 19:21:01 GMT
looking at the impedence tables posted on here am i right in thinking i could remove the output resistor from my panda without harming it or my d7000s?
25ohm and max power rating is quoted as 1800mw, by denon.
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Post by PinkFloyd on May 4, 2013 19:46:03 GMT
looking at the impedence tables posted on here am i right in thinking i could remove the output resistor from my panda without harming it or my d7000s? 25ohm and max power rating is quoted as 1800mw, by denon. I wouldn't remove it but would fit a 10ohm resistor on the spare socket (two of them)...... I certainly wouldn't go ZERO ohm..... try it and see how it sounds, that's the beauty of having two sockets to play with. Mike. |
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oldson
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Post by oldson on May 4, 2013 20:18:42 GMT
looking at the impedence tables posted on here am i right in thinking i could remove the output resistor from my panda without harming it or my d7000s? 25ohm and max power rating is quoted as 1800mw, by denon. I wouldn't remove it but would fit a 10ohm resistor on the spare socket (two of them)...... I certainly wouldn't go ZERO ohm..... try it and see how it sounds, that's the beauty of having two sockets to play with. Mike. just ordered a couple, thanks for the advice Mike |
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Post by PinkFloyd on May 4, 2013 20:32:03 GMT
I wouldn't remove it but would fit a 10ohm resistor on the spare socket (two of them)...... I certainly wouldn't go ZERO ohm..... try it and see how it sounds, that's the beauty of having two sockets to play with. Mike. just ordered a couple, thanks for the advice Mike I could have sent you a couple for free..... oh well, no harm done  |
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oldson
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Post by oldson on May 4, 2013 20:35:33 GMT
just ordered a couple, thanks for the advice Mike I could have sent you a couple for free..... oh well, no harm done oh bollox, never mind , was only £2, cheers anyway |
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Post by Deleted on May 4, 2013 22:02:51 GMT
looking at the impedence tables posted on here am i right in thinking i could remove the output resistor from my panda without harming it or my d7000s? 25ohm and max power rating is quoted as 1800mw, by denon. I guess that you could always do so, but at the risk of damaging the Panda in the event of an accidental S/C to the output, or perhaps your headphones if the volume control gets accidentally brushed or disturbed.. Far more important though is the potential and very real risk of damage to your hearing. You can't reverse hearing damage at this point in time. It just gets progressively worse. Perhaps in the future with Gene Therapy though... Kind Regards Alex |
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pingu
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Post by pingu on May 4, 2013 22:49:01 GMT
Hi, I second Alexs warning. After a bout of auto immune eurticaria I lost 50% of my hearing and untill it goes you really do not know how difficult it makes life. Yes I wear two aids but they are a help and nowhere near ideal and make using cans difficult On the up side my daughter has a reason to call me a "deaf old fart" now as I collect my pension  Take care Regards Martim |
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oldson
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Post by oldson on May 8, 2013 18:56:27 GMT
i take the warnings on board, thanks guys.
apart from my d7000 i am looking to get a set of open planar cans in the coming months.
my list includes he500, lcd2 rev2, and the he6.
i understand the latter needs a "monster amp", this was another reason for me wanting to connect my second hp jack without a resistor.
i should have mentioned this in my earlier post, i guess.
when i go to audition the above cans, i plan on taking my panda along. i certainly wont be forking out for the new hifiman amp (nearly £1200).
but i may consider getting a used speaker amp instead if i decide on the he6 (plus making my own adapter box, to save a bit of cash)
in the meantime as my d7000 will take upto 1800mw (according to denon), i thought after studying the tables posted on here that this would be fine albeit at lower volume levels.
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Post by invidiy on May 9, 2013 6:16:40 GMT
I've got half a dozen of these kits kicking about but they are PCB and parts only. Mike. I appreciate your effort, but probably it would be too much of a trouble, especially with ebay option available, because you'd have to send it all the way to Russia in that case p.s. not even a word from mall.hifidiy still |
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oldson
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Post by oldson on May 12, 2013 17:47:28 GMT
still trying to understand the imp tables on here (i know ,,, thick ba....d)  as an example Audeze quote optimal power for lcd-2 as being 1.4 watts. impedence of lcd-2 is 60 ohm. looking at the extract from the tables below Here are the powers for a Panda with a NO (0 Ohm) output resistor (rounded off values): HP impedance ....Class-A......Class-AB 32 Ohm ..............640mW.......3,125mW 64 Ohm ..............1,280mW ...1,560mW 150 Ohm ............670mW ......670mW 300 Ohm ............330mW ......330mW 600 Ohm.............170mW ......170mW am i correct in thinking, with no output resistor fitted the panda falls just shy of the 1.4W ("1280mw into 64 ohm")  ? thanks for any help |
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Post by Deleted on May 13, 2013 9:57:41 GMT
still trying to understand the imp tables on here (i know ,,, thick ba....d) as an example Audeze quote optimal power for lcd-2 as being 1.4 watts. impedence of lcd-2 is 60 ohm. looking at the extract from the tables below Here are the powers for a Panda with a NO (0 Ohm) output resistor (rounded off values): HP impedance ....Class-A......Class-AB 32 Ohm ..............640mW.......3,125mW 64 Ohm ..............1,280mW ...1,560mW 150 Ohm ............670mW ......670mW 300 Ohm ............330mW ......330mW 600 Ohm.............170mW ......170mW am i correct in thinking, with no output resistor fitted the panda falls just shy of the 1.4W ("1280mw into 64 ohm") ? thanks for any help According to the chart it is capable of up to 1.28W into 64 ohms in pure Class A, then it can do a little better by crossing over to Class AB beyond that, giving a maximum output level into 64 ohms of 1.56W. Try it with that 10 ohm output resistor that Mike suggested. You may be pleasantly surprised ! |
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oldson
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Post by oldson on May 22, 2013 20:37:40 GMT
still trying to understand the imp tables on here (i know ,,, thick ba....d) as an example Audeze quote optimal power for lcd-2 as being 1.4 watts. impedence of lcd-2 is 60 ohm. looking at the extract from the tables below Here are the powers for a Panda with a NO (0 Ohm) output resistor (rounded off values): HP impedance ....Class-A......Class-AB 32 Ohm ..............640mW.......3,125mW 64 Ohm ..............1,280mW ...1,560mW 150 Ohm ............670mW ......670mW 300 Ohm ............330mW ......330mW 600 Ohm.............170mW ......170mW am i correct in thinking, with no output resistor fitted the panda falls just shy of the 1.4W ("1280mw into 64 ohm") ? thanks for any help According to the chart it is capable of up to 1.28W into 64 ohms in pure Class A, then it can do a little better by crossing over to Class AB beyond that, giving a maximum output level into 64 ohms of 1.56W. Try it with that 10 ohm output resistor that Mike suggested. You may be pleasantly surprised ! have not fitted them yet, but this is what i bought www.ebay.co.uk/itm/140904426491?var=440097065583&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649did not know if i should go for these , carbon film or wire wound !!?? |
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Post by Deleted on May 22, 2013 22:07:25 GMT
They should be fine. Let's see how they go. You MAY even be able to stick 2 of them in parallel for a very small further increase in output level , but 10 ohms will be safer to experiment with, at least initially.
Alex
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oldson
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Post by oldson on May 31, 2013 23:07:54 GMT
"You should be aware that the Panda without output R's can supply 2.4W in the HD595 and when clipping 5W which could potentionally destroy the drivers if unattended and accidentally playing at full power." i am confused by this! the hd595 are 120 ohm so from the table below how do you get 2.4w? Here are the powers for a Panda with a NO (0 Ohm) output resistor (rounded off values): HP impedance ....Class-A......Class-AB 32 Ohm ..............640mW.......3,125mW 64 Ohm ..............1,280mW ...1,560mW 150 Ohm ............670mW ......670mW 300 Ohm ............330mW ......330mW 600 Ohm.............170mW ......170mW Read more: rockgrotto.proboards.com/thread/6605/panda-kit-build-thread?page=2#ixzz2Uukx6p9G |
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Post by Deleted on May 31, 2013 23:58:09 GMT
Me too ! It doesn't seem to make much sense. Perhaps you should PM the original poster for clarification of these remarks ? Regards Alex |
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oldson
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Post by oldson on Jun 1, 2013 19:39:20 GMT
Me too ! It doesn't seem to make much sense. Perhaps you should PM the original poster for clarification of these remarks ? Regards Alex i was under the impression all the 595's were 120 ohm. i have since learned this is not the case. the early ones were 50 ohm. |
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oldson
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Post by oldson on Jun 1, 2013 19:48:12 GMT
i put the 10 ohm resistors into my panda's spare HP socket today.
i was not brave enough to plug my d7000s straight in but used a 60 ohm adapter first.
cant honestly say i noticed much difference.
i did then turn volume right down and tried it without the adapter.
i very gingerly built the volume up, but stopped when it became apparent something was wrong.
had sound only from right channel (and what was coming out did not sound good, either)
needless to say i scrapped this little experiment, and will not risk it again.
have left the resistors in place for when i finally get my chosen ortho's.
so glad i listened to the advice of fitting the resistors rather than going down to zero ohms.
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Post by PinkFloyd on Jun 1, 2013 21:30:42 GMT
"Hearing" is a sense that you don't want to lose (IMO)....
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Post by imstimpy on Nov 18, 2013 21:06:46 GMT
Has anybody added a crossfeed circuit to the amplifier? I've been using the HeadRoom Micro for years and love their circuit. headwize.com/?page_id=654headwize.com/?page_id=774My Panda kit is in the mail. Since I haven't done an electronics project in a number of years, I'll likely start with a vanilla build. Afterwards, I hope to make sense of the other mods listed here and A/B the changes. |
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Post by bronc on Nov 28, 2013 16:27:18 GMT
Hello friends! I read the first ten pages of the main thread about the Panda headphone amp and got hyped immediately! I am looking for a headphone amp project to use until a move to a more permanent home where I can bring the rest of my hi-fi equipment next year. Are there any kits left or do I have to order one from the hifidiy? I might also get a transformer and any other bits and pieces from Pink Floyd..  Thanks! |
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Post by imstimpy on Nov 29, 2013 14:23:41 GMT
I ordered mine from hifidiy before I realized some kits had been provided by Rock Grotto. Anyhow, I received it last week, sorted the parts, and began populating a few days ago. I hope to finish the resistors today. Most people here bought the board and components then supplied the case and power supply separately. Once I get a little further I plan to try and collect information on completing the kit with the Panda transformer to 120v as well as collecting all the mods people have done. I need to put in an order for wires and a couple misc components before I can fully complete the build, though. From a novice perspective, it is a little intimidating that the PCB is labeled with component values. The grubDAC is marked with R# and C# with a BOM referencing the labels. The Panda is component values and a BOM of components. While matching resistors isn't a big deal, the mislabeled diodes on both the PCB and the BOM are a little sketchy. The best step-by-step on the build can be found here: www.mcfrede.dk/projects/panda_headamp/panda_headamp_01.shtml . |
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Post by PinkFloyd on Nov 29, 2013 22:32:46 GMT
I ordered mine from hifidiy before I realized some kits had been provided by Rock Grotto. Anyhow, I received it last week, sorted the parts, and began populating a few days ago. I hope to finish the resistors today. Most people here bought the board and components then supplied the case and power supply separately. Once I get a little further I plan to try and collect information on completing the kit with the Panda transformer to 120v as well as collecting all the mods people have done. I need to put in an order for wires and a couple misc components before I can fully complete the build, though. From a novice perspective, it is a little intimidating that the PCB is labeled with component values. The grubDAC is marked with R# and C# with a BOM referencing the labels. The Panda is component values and a BOM of components. While matching resistors isn't a big deal, the mislabeled diodes on both the PCB and the BOM are a little sketchy. The best step-by-step on the build can be found here: www.mcfrede.dk/projects/panda_headamp/panda_headamp_01.shtml . A trained gibbon could put one of these together in a couple of hours. The kits don't come with any instructions (which is why they are so cheap) but most of the "monkey sees, monkey does" photos that I put up (somewhere here) shows you "clearly" where everything goes. The Mcfrede guy got all his info from me (and this forum) and it's good to see that he has put a few photos up to make the build even easier for a newbie to understand If you look further into this forum you will probably find a comprehensive "build" guide for the Panda (I vaguely remember doing one) just a case of finding it and cherrypicking relevant parts out of threads. Unfortunately, nobody at HIFIDIY seems good at writing an "English" tutorial.... much the same way as I wouldn't have a clue how to write a tutorial in Chinese but the actual amp, itself, is a superb design and the quality of the parts / PCB is extremely good for the money. What parts are you looking for?, let me know and I'll probably have them in stock..... all the parts for the PCB come with the kit so you'll be looking for an enclosure, a toroidal transformer, a switch, a headphone socket (or two), Phono sockets and some hook up wire...... oh, and a couple of output resistors (or four) if you choose to go dual output impedance..... It's a lovely sounding amp and actually VERY easy to put together (if you're used to home brew amps) it will knock seven bells of shit out of any commercially produced amp by quite some margin. Mike. |
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Post by PinkFloyd on Nov 29, 2013 22:40:17 GMT
Spend a few hours trawling through this thread rockgrotto.proboards.com/thread/6609/good-vfm-panda-headphone-amp?page=3#page=1It's the thread that got the "global" Panda party started  48 pages of Pandalicious randomness to read through..... it's all about cherry picking on the journey (and maybe partaking in a few bamboo leaves)...... You may find what you are looking for within these scriptures grasshopper  Pinkie. |
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Post by imstimpy on Nov 30, 2013 4:15:22 GMT
Thanks for the responses Mike. So far, the build has gone very well. I'm meticulous, so it has been slow. I successfully built the grubDAC a few days ago (which was harder than the Panda), but otherwise I haven't done a DIY soldering project in about ten years. The hardest part of the Panda so far has been deciphering why the different pieces go in different areas, finding them on the circuit diagram and the PCB, and understanding the few erroneous labels in the BOM/PCB. I've got a neat list of items that have been previously documented in various places: Errors -> Correction (location on PCB): Dale resistor 1/2W3 x4 (populated at 2.2)) Gold 25V100UF x1 -> 16V100UF x1 (populated at cap location 100UF) voltage regulator tube 3.9V x1 -> diode 3.9V x2 (populated at diode location 3.9V) voltage regulator tube 18V x4 -> diode 18V IN4746 x4 (populated at diode location 18v) Warnings: There are both Dale 1K and KOA 1/4W1K resistors on the BOM and are both labeled 1K on the PCB There are Dale 1.47K and Dale 1/2W1.5K resistors and are both labeled 1.5K on the PCB. The striped KOA resistors are all located near the power supply side. The larger Dale resistors go in the wider spaces nearest to the output side.  |
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Post by imstimpy on Nov 30, 2013 4:28:15 GMT
What parts are you looking for?, let me know and I'll probably have them in stock..... all the parts for the PCB come with the kit so you'll be looking for an enclosure, a toroidal transformer, a switch, a headphone socket (or two), Phono sockets and some hook up wire...... oh, and a couple of output resistors (or four) if you choose to go dual output impedance..... It's a lovely sounding amp and actually VERY easy to put together (if you're used to home brew amps) it will knock seven bells of shit out of any commercially produced amp by quite some margin. Mike. I'm a little unsure about the transformer. I have the one pictured here but it definitely isn't a torroid. You don't know of a source for torroids for those of us across the water in the US, do you? I'd be happy to buy some bits from you but I figure the shipping to the US would be atrocious. Otherwise I'm just looking for more information on the mods you did to stabilize(?) the input power, and anything else people have found to improve the amplifier. I have made a first pass through most of the Panda threads, but I haven't collated all the modifications into a digestible format yet. I know I need to source some ~120 ohm capacitors for the output impedance for my K701s. Ceramic, Poly, carbon? I'm not really sure how to go about selecting the type of output cap. |
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Thanks!
48 pages of Pandalicious randomness to read through..... it's all about cherry picking on the journey (and maybe partaking in a few bamboo leaves)...... You may find what you are looking for within these scriptures grasshopper 