Soooooo after a long day out with the family, my resistors had arrived early in from Parts Connexion. Was planning on ordering from the USA (located in NJ) but I had asked them a few questions, and they were amazing with some help pointing towards what I needed and some options, that I had to give them my business even with the shipping from Canada. Not like my order was huge, only 20 bucks, but also on their side they know I only needed a few resistors and had no issues answering all my questions.
So below are some considerations that I selected my resistors. Just an FYI I think all the takman upgraded resistors in the kit are 0.5W resistors, which makes sense for the stock zphone (120-670ohms).
Why does this make sense? Lets take a look at my guesstimate at what the power rating is for each of the positions below. My assumption is that the amp is advertised at 9w of power but doesnt tell you at what ohms, so I am guessing it makes it at 8ohms like every other 300b amp. We can guess using an online calculator to get a generic number that the amp potentially is making at the ohm below.
Position 1 : 670Ω Watt = 0.107
Position 2 : 550Ω Watt = 0.131
Position 3 : 240Ω Watt = 0.3
Position 4 : 120Ω Watt = 0.599
The new positions that I have below and a guess at the power rating.
Position 1 : 240Ω Watt = 0.3
Position 2 : 210Ω Watt = 0.342
Position 3 : 40Ω Watt = 1.8
Position 4 : 10Ω Watt = 7.2
I ordered a 5w for the 10Ω, and a 1w for the 3 remaining. Realistically, I probably could have ordered a 2W 10Ω resistor, and probably 0.5W for the rest. As position 4 uses only 1 resistor, it will take the full voltage brunt, and the other 3 positions will be sharing the load across at least 2 resistors so I dont believe it would have been an issue. This is my understanding of how voltage is shared across multiple resistors but someone can correct me if I am wrong.
Your selection probably depends on your use case? I selected a 5W as I dont have any headphones that go below 30W that are power hogs, and at 30W this amp should make around 2.4W of power. Of course like mentioned earlier, this is all just estimates as Elekit does not provide in-depth power measurements. I also wanted resistors that were all similar sizes and slightly over spec because I am crazy.
Below is what I ordered.
Mills Resistor 10R Ohm 5W MRA-5 Series (Qty 2)
$5.92
Takman Resistor 200R Ohm 1W REX Series (Qty 2)
$2.10
Takman Resistor 30R Ohm 1W REX Series (Qty 2)
$2.10
So the reason I mentioned earlier the that the stock resistors are probably 0.5W (might be 0.25, not sure) is because the wires on the new resistors I ordered are larger than the resistors that come with the kit and do not fit the PCB.
Well, I have been in a bad mood for awhile due to the headphone jack on this amp for too long and nothing was going to stop me tonight now that I had my resistors in hand.
I had the below Pin Vice on hand as I needed it to drill out my Hakko Desolder gun a few months ago.
https://www.amazon.com/gp/product/B07FJ6VD2P/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
So after using the Hakko 301 desolder gun to remove the stock resistors, I went slowly and used the pin vice to drill out the PCB holes SLIGHTLY larger. IF you decide to do this, please go slowly without pushing hard(very slightly). You want the drill bit to do all the work. If you push too hard, there is a chance you can lift the pad and that will require you to repair the PCB. I also used my finger right against the hole I was hand drilling slowly to be able to feel when it was coming through. It also stops me from going too fast or pushing too hard as I will stab straight into my finger haha.
Also make sure that you maintain at least a 1cm clearance from the edge of the PCB and the edge of the resistor. As my resistors were larger, if you do not maintain the 1cm clearance, you will tap the case when you are reinstalling the pcb. I just pushed back the resistors as I installed them lifted off the pcb to get my clearance I needed.
So the conclusion, this works as intended. I have much more volume in Positions 1 (240 ohms) with my 300 ohm headphones (zmf/sennheiser) and I am able to finally drive my planar headphones off of position 4 (10 ohm). I am getting the same power that I was getting off of using the speaker tap adaptors. Everything sounds great, and finally the amp is where I am happy with it.
Below is a picture of the resistor locations.
Picture of the Pin Vice I used which I linked earlier.
Picture once everything was installed.
Last bonus picture. Not sure if this is common knowledge, but I got jealous of Victor's install of his transformers as they were much cleaner than mine. He told me that I could get hex standoffs so you can tuck your wires under the transformers, instead of on the side. This sounded great to me as I could create a bit more separation between the difference wires, and also looks great. Not that anyone will ever see it, but made me feel better.
Victor, if you are reading this, Elekit really need to fix this on this amp. The headphone tap is really broken and cant drive anything below 120 ohms properly. Position 1 and 2 is honestly completely useless, and lower ohm taps need to be setup for further flexibility. The output ohms for the headphone taps across different models of Elekit amps seem to point towards they are realizing this is a problem and are experimenting. Hopefully they figure something out for the 8600S as well. To be honest, if they shared the Zphone in their specs, I probably would have bought either the 8800 or 8200 amp instead. Another bad habit, manufacturer really should share more specs than is currently shared as specs on their amps across their vendors.
This amp sounds too good to have something this simple causing issues for the headphone jack. Its literally switching 6 resistors to different specs and probably wouldnt cost anymore than the resistors they are using currently. If there is an increase in cost, maybe it will go up 5$. Maybe they are purely focused on the speaker amp portion of the amp and don't care about the headphone side? I am not sure.
Anyways. I am happy and off to listen to some music before sleeping.
So below are some considerations that I selected my resistors. Just an FYI I think all the takman upgraded resistors in the kit are 0.5W resistors, which makes sense for the stock zphone (120-670ohms).
Why does this make sense? Lets take a look at my guesstimate at what the power rating is for each of the positions below. My assumption is that the amp is advertised at 9w of power but doesnt tell you at what ohms, so I am guessing it makes it at 8ohms like every other 300b amp. We can guess using an online calculator to get a generic number that the amp potentially is making at the ohm below.
Position 1 : 670Ω Watt = 0.107
Position 2 : 550Ω Watt = 0.131
Position 3 : 240Ω Watt = 0.3
Position 4 : 120Ω Watt = 0.599
The new positions that I have below and a guess at the power rating.
Position 1 : 240Ω Watt = 0.3
Position 2 : 210Ω Watt = 0.342
Position 3 : 40Ω Watt = 1.8
Position 4 : 10Ω Watt = 7.2
I ordered a 5w for the 10Ω, and a 1w for the 3 remaining. Realistically, I probably could have ordered a 2W 10Ω resistor, and probably 0.5W for the rest. As position 4 uses only 1 resistor, it will take the full voltage brunt, and the other 3 positions will be sharing the load across at least 2 resistors so I dont believe it would have been an issue. This is my understanding of how voltage is shared across multiple resistors but someone can correct me if I am wrong.
Your selection probably depends on your use case? I selected a 5W as I dont have any headphones that go below 30W that are power hogs, and at 30W this amp should make around 2.4W of power. Of course like mentioned earlier, this is all just estimates as Elekit does not provide in-depth power measurements. I also wanted resistors that were all similar sizes and slightly over spec because I am crazy.
Below is what I ordered.
Mills Resistor 10R Ohm 5W MRA-5 Series (Qty 2)
$5.92
Takman Resistor 200R Ohm 1W REX Series (Qty 2)
$2.10
Takman Resistor 30R Ohm 1W REX Series (Qty 2)
$2.10
So the reason I mentioned earlier the that the stock resistors are probably 0.5W (might be 0.25, not sure) is because the wires on the new resistors I ordered are larger than the resistors that come with the kit and do not fit the PCB.
Well, I have been in a bad mood for awhile due to the headphone jack on this amp for too long and nothing was going to stop me tonight now that I had my resistors in hand.
I had the below Pin Vice on hand as I needed it to drill out my Hakko Desolder gun a few months ago.
https://www.amazon.com/gp/product/B07FJ6VD2P/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
So after using the Hakko 301 desolder gun to remove the stock resistors, I went slowly and used the pin vice to drill out the PCB holes SLIGHTLY larger. IF you decide to do this, please go slowly without pushing hard(very slightly). You want the drill bit to do all the work. If you push too hard, there is a chance you can lift the pad and that will require you to repair the PCB. I also used my finger right against the hole I was hand drilling slowly to be able to feel when it was coming through. It also stops me from going too fast or pushing too hard as I will stab straight into my finger haha.
Also make sure that you maintain at least a 1cm clearance from the edge of the PCB and the edge of the resistor. As my resistors were larger, if you do not maintain the 1cm clearance, you will tap the case when you are reinstalling the pcb. I just pushed back the resistors as I installed them lifted off the pcb to get my clearance I needed.
So the conclusion, this works as intended. I have much more volume in Positions 1 (240 ohms) with my 300 ohm headphones (zmf/sennheiser) and I am able to finally drive my planar headphones off of position 4 (10 ohm). I am getting the same power that I was getting off of using the speaker tap adaptors. Everything sounds great, and finally the amp is where I am happy with it.
Below is a picture of the resistor locations.
Picture of the Pin Vice I used which I linked earlier.
Picture once everything was installed.
Last bonus picture. Not sure if this is common knowledge, but I got jealous of Victor's install of his transformers as they were much cleaner than mine. He told me that I could get hex standoffs so you can tuck your wires under the transformers, instead of on the side. This sounded great to me as I could create a bit more separation between the difference wires, and also looks great. Not that anyone will ever see it, but made me feel better.
Victor, if you are reading this, Elekit really need to fix this on this amp. The headphone tap is really broken and cant drive anything below 120 ohms properly. Position 1 and 2 is honestly completely useless, and lower ohm taps need to be setup for further flexibility. The output ohms for the headphone taps across different models of Elekit amps seem to point towards they are realizing this is a problem and are experimenting. Hopefully they figure something out for the 8600S as well. To be honest, if they shared the Zphone in their specs, I probably would have bought either the 8800 or 8200 amp instead. Another bad habit, manufacturer really should share more specs than is currently shared as specs on their amps across their vendors.
This amp sounds too good to have something this simple causing issues for the headphone jack. Its literally switching 6 resistors to different specs and probably wouldnt cost anymore than the resistors they are using currently. If there is an increase in cost, maybe it will go up 5$. Maybe they are purely focused on the speaker amp portion of the amp and don't care about the headphone side? I am not sure.
Anyways. I am happy and off to listen to some music before sleeping.
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Headphones rated at 20 Ohms are current driven from the >120 Ohm output in position 4 and very likely sound different especially in the bass region than they would do when voltage driven. You can try bypassing R129/R229 on the PCB side, which will give you an indication about sonic differences. Be careful with the volume though as you will connect the phones straight to the OPT!
So if I were to replace the two 120 ohm resistors at R129 and R229 (position 4) with 20 ohm resistors, then I’m essentially matching the impedance on my Audeze HPs. Right? Seems simple enough and since it’s such a PIA the switch the couplers for different headphone matching, I’m essentially eliminating use of my Senn HD600’s. Or I could match those with higher value resistors to get to 600 ohms. Right?
Sorry for the nube questions, but I’m quickly learning!!!
Sorry for the nube questions, but I’m quickly learning!!!
Hello, so no you wouldnt be eliminating use of the Senn HD600's. I would probably recommend going a little bit lower on the 2 resistors, to give you a little bit of buffer room, but 20ohm should be fine. Generally in my experience the more multiples of resistance you have, the more neutral the sound will get off a tube amp, and the close to 1 to 1 impedance match you will get a more romantic tubey euphonic sound. I do enjoy the close matching for my dynamic headphones.
If you switch those 2 location resistors, you will still be able to use the amp with your Senn HD600's. They are 300ohm headphone so lets see how your output ohms will change.
Position 1 will go from 670 to 570
Position 2 will go from 550 to 450
Position 3 will go from 240 to 140
Position 4 will go from 120 to 20.
If you enjoyed position 1 and 2 previously on your HD600's, the new position 1 and 2 should be fairly similar, you will probably get a bit more power.
Position 3 will become almost the same as your old Position 4, and your new Position 4 will give you the 20 ohm for planars.
As mentioned earlier, you are probably not getting enough power to your LCD2c, but due to how sensitive the headphone is, they probably sound good to your ears and get loud enough. But I am guessing you can probably turn the volume knob pretty high up. My experience in this side of impedance matching is reduced bass, bloated mids, and as you turn up the power (headphone trying to pull more power) you will end up with the highs increasing in volume, but the lower end not following (low end like bass requires the most power, lack of power = lack of low end oomph first) which creates a brighter presentation than the headphones are designed for.
In your case, if you switch those 2 resistors, you will essentially be shifting position 4 to 3 (120ohm vs 140ohm should be fairly negligible) and giving yourself a new 20ohm tap that you can experiment with and give flexibility.
Also to note, your Senn HD600 will work perfectly fine off the 20ohm tap as well. It should sound a bit more neutral, and also have a more power being fed to it. You will probably not be able to turn the volume knob as much. Example with my 300ohm headphones, I can turn my knob around 8-9 oclock depending on how loud I want on 240 ohm tap, but I am between 7-8 on the 10ohm tap.
Good luck!
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Awesome! I am reading through your post again and again and it is very helpful. I'm loath to do any drilling on the PCB, so might replace the resistors with the 0.5W Takman's and keep the volume levels within reason, hoping this will avoid overload on the resistors... Appreciate all of the insights on this board! What a fun project and a great way to learn about electronics while following a passion for music! Happy holidays!
good luck! let us know how it goes and your experience. just double check with the vendor and make sure to get the 20R resistor. I was new to buying resistors and the numbering scheme is highly confusing for me.
I believe Takman Resistor 20R Ohm 0.5W REX Series this is the resistor you are looking for. To reiterate im not sure if they are using .25w or .50w resistors in those locations, but I measured around 9mm for the length of the resistor, so that best correlates with a .5W resistor. Would be awesome if you confirm .5W resistors fit without adjustments. Per the Takman info PDF .5W resistors are 9mm +-.5mm.
I believe Takman Resistor 20R Ohm 0.5W REX Series this is the resistor you are looking for. To reiterate im not sure if they are using .25w or .50w resistors in those locations, but I measured around 9mm for the length of the resistor, so that best correlates with a .5W resistor. Would be awesome if you confirm .5W resistors fit without adjustments. Per the Takman info PDF .5W resistors are 9mm +-.5mm.
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The output impedance does not need to match the rated impedance of the phones. That was a different story with long telephone lines.
Most headphones work well when driven from 20-30% of their specified impedance. 6xx and 8xx Sennheisers require about 60-100 Ohms for a slight bass boost, most other models are fine with very low output impedances of driving amps.
I have a question concerning the Elekit 8600S that I am currently building...my HiFiman Sandaras have a impedance of 32 ohms. I got curious about headphone impedance while reading this post. I am very new to hifi so please have forgiveness for this question. When I Google headphone impedance matching the 1-8 rule keeps popping up. It states that your headphone impedance ideally should be 1/8 of the source output impedance. I want to set my 8600S up in advance while I am constructing it. With my impedance being 32 ohms and using the Elekit (official) values set as :
1 - 670
2 - 550
3 - 240
4 - 120
How in the world am I going to get 4 ohms which follows the 1 - 8 rule ? I am not really to concerned because these headphones sound great using the Wellsenton R8. Again I am just learning and appreciate any advice or opinions you have...Thanks
1 - 670
2 - 550
3 - 240
4 - 120
How in the world am I going to get 4 ohms which follows the 1 - 8 rule ? I am not really to concerned because these headphones sound great using the Wellsenton R8. Again I am just learning and appreciate any advice or opinions you have...Thanks
