Do 150 ohm headphones need an amp. How do I know if I need an amplifier? In this particular case, the spec is more like a guideline. Factors such as headphone sensitivity, audio source quality, dynamic range, impedance matching, noise reduction, and personal listening preferences all play a role in determining the need for So the answer to your question is that you could be fine, depending on the headphones, and depending on how loud you listen. This may remove the need for an external headphone amplifier. This option commonly bypasses the internal amplifier, so depending on their sensitivity Jan 5, 2014 · Thinking of buying Beyerdynamic DT770 or DT990 250 ohm. High ipedance (150 Ohm) headphones working ok with cheap ass mp3 player (transcend MP350) and random laptop. Impedance is the electrical resistance of the driver unit present inside the headphones, and lower ohm headphones require less power to deliver a reasonable listening volume. So the manufacturer just tells customers - "up to 150 ohm most headphones that we know of should work well; above that value we do not want to make any guarantees". Jun 30, 2023 · Audio Source Quality: The quality of the audio source can significantly impact the need for amplification with 50-ohm headphones. On the other hand, low-impedance headphones (below 50 ohms) can be driven effectively by most portable devices and do not necessarily require high-powered amps as too much power and you Nov 15, 2020 · You don't really need an amp for 32 Ohm's mid sensitive headphones, even most phones can deliver that much (1~1. High-impedance headphones (over 100 ohms) often benefit from dedicated headphone amps. S. Mar 14, 2025 · A good amplifier will drive same voltage into 8 ohms and 150 ohms. g. Do not use an external amplifier with active noise-cancelling headphones or any other type of headphones that contain a built-in amplifier. The higher the output impedance, the more dramatic the change. Is there a quick formula to calculate how much mW will be given at any impedance? Is it just linear? The scale is roughly linear in that double the Ohms generally means half the Wattage, assuming that the amplifier can keep Current and Voltage constant. Jan 27, 2025 · The headphones will still work, but you'll be missing out on their full capabilities, similar to trying to power a home theater speaker with a portable radio. I'm looking for an affordable headphone amp that can help me out here. Will I benefit from a DAC or Amp or both in this regard? If so which one? (I use my headphones with a pc. This guide will help you navigate the process step by step. If I want to drive a high impedance headphone, e. High Impedance – 100 Ohm and above. Do i need an amp or will my built in audio solution work? Apr 10, 2023 · Discover the definition, benefits, and how to choose the best high ohm headphones. A desktop amp is key to making sure you get good performance out of these premium headphones. Headphone impedance is typically rated between 8-600 ohms, with a standard around 32 ohms becoming increasingly common. Nov 24, 2017 · What's the difference between 2 sets of headphones, one has 38 ohms and the other has 150 ohms, will an AMP/DAC improve the quality of the 150 ohms headphones? I understand Ohms is resistance, but the higher the ohms the better the quality of the music would be with proper AMP/DAC? Frequently Asked Questions Do I need a headphone amplifier for all headphones? Not necessarily. Impedance is analogous to resistance in DC circuitry, and higher impedance headphones need a higher You can technically use 250-ohm headphones without an amplifier; however, the audio that is produced will be sub-par to what they are designed for, outputting a meager volume (if any volume at all), having distortion in low frequencies, and being muddy. 5mm input as an audio connection for my 150 ohms headphones. I've never bought headphone amp before, so I thought I'd ask you lovely bastards for some suggestions! Jun 26, 2025 · Can a PC Handle 80 Ohm Headphones: What You Need To Know about sound quality, volume issues, and when to use a headphone amp. 5X gain with 300 ohm headphones and only 0. My headphones are the Beyerdynamic DT 990 250 ohm. com/dms3tvSnapchat @dms3tvIF you want early access Oct 20, 2004 · It sounds good and far better then a normal headphone jack yes but at higher volumes you can just tell it isn't getting enough power and really needs a dedicated amp (I ordered an Asgard 2 yesterday since my Little Dot is getting stale). Recommendations and product examples are included. Buying >200 Ω headphones may require a headphone amp/DAC if your device cannot sufficiently drive them. 95. I don’t need a tube amp. How do I know if my Amp is good enough to power certain headphones? Outside asking here, what specifications on Amps / Headphones do I need to see if they'll work together? For example let's say I have a Schiit Sep 3, 2022 · Try the HD800S with the EVO 150 and see how it works for you. com/dms3tvInstagram. In this comprehensive article, we’ll explore the world of 48 … Do 48 ohm headphones need an amp Jun 12, 2025 · When it comes to audio equipment, one of the most crucial decisions you’ll make is whether or not to invest in an amplifier (amp) for your speakers. Gray Area – 32 – 100 Ohm. The headphone itself is the most important part of a personal audio system. Dec 16, 2020 · I need help from the knowledgeable people here. This leaves many people with technical questions about their headphones, like do you need an amp with 80 ohm headphones? Typically amps that can power 600 ohms headphones can also do 150 ohms without a problem. Shop now and hear the difference! They have an impedance of 20 ohms. Jan 6, 2022 · Reference-class open-back headphones from Sennheiser deliver audiophile performance when paired with a suitable headphone amplifier or hi-resolution audio player, with a nominal impedance of 150 ohms. Let's compare that to something like the Scarlett 2i2, which is a popular inexpensive audio interface with a headphone amp. Need new cans - my DT770s finally kicked the bucket after 15 years (RIP) Looking at the Sennheiser HD600s, but they are 300 ohms and my interface (Focusrite Scarlett 18i20) is max 250 ohms for headphones. It is tested during production with a standardised audio signal so that headphones achieve their intended “nominal impedance”. Is there a drawback other than low max volume? Do I lose quality, or thy don't play all frequencies accurately? Here you can ask which headphone is better, which amp you should buy, which gear best fit your budget and anything related to headphone comparisons and purchasing. It'll probably drive the DT990s but unless you need the XLR inputs. May 30, 2017 · They can be used without an amp, but the volume will be lower than what you would hear with a lower impedance headphone. However, high-impedance headphones (above 100 ohms) usually benefit from a dedicated amplifier to really shine. Understanding Impedance: Impedance is a measure of electrical Nov 24, 2018 · What is important to drive headphone properly? In many other forums i read that not just the voltage but also the current is very important and some headphones like high current output, but usually most amplifier only strong with voltage and thats why many hard to drive phone sounds bad from Sep 1, 2021 · What do headphones ohms ratings mean? Do high-impedance headphones sound better? Compare low, medium, and high-impedance headphones on the zZounds Blog. I have never owned a professional pair of headphones, so I'm not sure if a soundcard can be as good as an amp, or do I just need both? A place for making the right decision when purchasing new headphones. Both of the headphones you mentioned probably don't really need a dedicated amp because they are not incredibly high impedance (58x is 150 ohm and 770 is 80 ohm). Specifically, if you’re using 80 Ohm headphones, do you need an amp to get the best sound quality? In this article, we’ll delve into the world of audio equipment and explore the ins and outs of using an amp with 80 Ohm Dec 8, 2023 · Here comes the science bit: impedance (measured in ohms or Ω) is an electrical engineering term and denotes the electrical resistance of voice coils in the transducer of wired headphones. Feb 12, 2011 · As for voltage/power, I'd have to look up the numbers and do the math but I think they need at least around 3 Vrms (150 mW at 60 ohms, 560 mW at 16 ohms or 15 mW at 600 ohms) to play fairly loud. The DT880-600 needs a higher output voltage. If you’re not yet familiar with what a headphone amp is and how it works Headphone amps do not have to cost that much I have 2 300 ohm no-name headphone amps that cost less then $20 on eBay the 500 ohm no-name amp was like $32 on eBay I actually purchased 2 more but I returned them because it was total overkill! Feb 25, 2025 · Low Impedance – 16 - 32 Ohm. DT880 600 Ohm, what output power should my headphone amplifier have? The DT880 600 Ohms has a sensitivity of 97db. However, certain types of headphones, especially those with high impedance or low sensitivity, can benefit significantly from a headphone amp. The Scarlet isn't really a headphone amp. Just like your mains socket can drive different loads like 1000W heater and also a 10W light bulb. But honestly, I can't tell you what your headphones will sound like. Common devices like phones and computers won't do well with high impedance headphones, so if you want to use them with those devices, you'll need to shoot for 32 or 80 Ω headphone models. Enter the amplifier’s output impedance, also in Ohms (check the amp’s user manual). A headphone amp maximizes the full sound quality potential of top headphones. Jun 30, 2023 · Conclusion: While 150-ohm headphones can be driven by various audio sources, the use of a dedicated headphone amplifier can offer significant benefits. The HD800S is a 300 ohm headphone, and doesn’t need a ton of power to run. Feb 28, 2025 · High impedance models (above 50Ω) are the sophisticated audiophiles at the gathering – they need proper amplification to show off their talents, but when properly powered, they reward you with superior control, detail, and finesse. For most headphone amps, a 32 ohm load is often limited by the maximum amount of CURRENT the amp can put out before distorting, while the maximum output voltage into 150 ohms is limited by the We would like to show you a description here but the site won’t allow us. While many portable devices can drive 50-ohm headphones to reasonable volume levels, the quality of the audio output can vary. That suggests that the performance of 250 Ohm headphones using the 'regular' headphone jack on the Mac Pro 2019 model will be lower than you would like, even turned all the way up. Mar 26, 2023 · So if you’re looking for great sound quality from your 80 ohm headphones – investing in an appropriate amp could be worth it! Are There Any Alternatives To Using An Amp With Headphones? When it comes to amplifying sound from headphones, the question of whether or not an amp is necessary arises. The WAD is specified for 1W and has a >250 Ohm tap so expect about 0. Balanced connections further enhance sound quality for high-impedance headphones. Dedicated headphone amplifiers often provide cleaner power, improved signal-to-noise ratio, and better overall audio performance. By connecting a headphone amp to your audio setup, you can unlock the full potential of your 32 ohm headphones or speakers. Hence amplification in some form is recommended for 250 ohm headphones. May 2, 2021 · Hi all! Been reading through a couple threads and I have a couple questions. Apr 28, 2015 · The generally held rule of thumb is that the amp output impedance should be 1/8 the headphone impedance for best result (e. This means if you are monitoring a recording with a band, you can split the output 4 ways and they would all hear undistorted sound. In this article, we explore the dynamics of headphone impedance, discuss the significance of amplification, and help you determine whether 80-ohm headphones truly necessitate an There are two basic reasons why you might want to consider buying a dedicated headphone amplifier: getting more volume and/or getting better sound. Dec 31, 2024 · Low-impedance headphones (around 16-32 ohms) typically don’t need an external amp because your phone or laptop can do the job. 87V 120mW (32Ω) = 1. So why did Sennheiser make them 300 ohms? Couldn't their engineers make them 120-150 ohm? You need to look at the resistance (ohms) and the sensitivity (three different ways of presenting it unfortunately) together. Nov 30, 2024 · High-impedance headphones (above 100 ohms) need more power to produce sound without distortion, making a dedicated headphone amplifier essential for unlocking their full potential. Note however that this is absolutely NOT to say that the Apple USB-C dongle is the only DAC/amp you need. Get an amp if you can't reach 150% of your max listening volume (enough to handle impedance spikes), or if you are able to confirm the output impedance of your sound card/motherboard is too high and puts you in a bad place with regards to the damping ratio. Dec 27, 2023 · High-impedance headphones (over 100 ohms) require more power to deliver the best audio performance and, thus, need an amplifier with a higher output impedance. Related: What is Sensitivity in Headphones? They don’t sound that great plugged into a phone or laptop, but once you pair them with an amp that provides enough power, boy howdy do they sound amazing. Now, you don't need a separate headphone amplifier for each one of the four headphones you own–one will do–but it must be the right one. Specifically, if you’re working with 80 ohms, you might wonder if an amp is necessary or just a luxury. An amplifier increases the power and voltage supplied to the headphones, resulting in improved audio quality and increased volume. Jul 9, 2025 · Higher impedance headphones (250-600 ohms) may be underpowered by your headphone amp, which makes them underperform. May 12, 2023 · 50-ohm headphones might need an amp if they have low sensitivity (usually they don’t). Aug 22, 2024 · Exploring recording and monitoring situations in studios and live events that would call for a headphone amplifier. Headphones in this range work well with devices that have weak built-in amplifiers like phones, laptops, etc. For example, an amp with a 120 ohm output impedance with 5X gain at no load, will have only 3. Headphones have come a long way, and today they are almost as complicated to understand as any other piece of audio equipment. Oct 26, 2017 · To the best of my knowledge, there's no such thing as a headphone amp that is optimized for a pair of 150 ohm headphones, any more than there is a stereo system amplifier that is optimized only or mainly for 8 0hm loudspeakers. . 150ohms is considered rather high, but that doesn't mean that they're hard to drive. It has a particularly large driver too, so the headphones will need something more sufficient to synergize with. Jun 23, 2025 · When it comes to choosing the right equipment for your audio setup, one of the most common questions is whether or not you need an amplifier (amp) for your headphones. ) If not, are there any headphones within 150-250 dollars that offer similar naturalness of the H 560 S with more bass/depth in closed back? Edit: Equalizer APO with peace solved the bass problem while keeping clarity! Mar 24, 2024 · You’ll need an amp that can handle a wide impedance range to accommodate various headphones, from low-impedance models (16-50 ohms) to high-impedance units (250-600 ohms). A place for making the right decision when purchasing new headphones. Bluetooth headphones will never need an amplifier, as the headphones themselves deliver the power to the drivers internally. Learn about the advantages and disadvantages of high ohm vs low ohm headphones. Do you need an amplifier? How much power do you really need? And what misconceptions exist about hard to drive headphones in general?Headphone Power Calculat Aug 26, 2024 · What I will bring you in this guide Introduction How to choose a headphone amp Portable vs. Sep 24, 2022 · For headphones with an impedance of 150 to 1k ohms, the headphone jack delivers 3 volts RMS. Click on the “Calculate” button, and the tool will display the ratio between your headphone and amplifier impedance. Dec 1, 2024 · Adding a headphone amp to your audio setup can be a game-changer, but with so many options on the market, choosing the right one can feel overwhelming. If you’ve come across 48 ohm headphones and are wondering whether they require a dedicated headphone amplifier to shine, you’re in the right place. Low-impedance headphones (under 100 ohms) are easily driven by most devices. So in theory this motherboard should be enough to drive this thing. Desktop Power Considerations Output Impedance of the Amp Sensitivity & Impedance Some Amp recommendations Final Word So without further ado, let’s get started! Introduction In your research for the best studio headphones for mixing, the best headphone under $500, etc. By using an amplifier, you can experience the full dynamic range of your headphones and achieve better resolution and clarity in your music. High-Impedance Headphones Impedance, measured in ohms, is a specification that determines how much electrical resistance a headphone has Apr 26, 2025 · The Apple USB-C dongle is one of the best starter DAC/amps you can get. you need an amp with at least +/- 24V power supply rails for a 1 to 1 replacement in output power Dec 8, 2023 · Here comes the science bit: impedance (measured in ohms or Ω) is an electrical engineering term and denotes the electrical resistance of voice coils in the transducer of wired headphones. Dec 13, 2016 · I bought Audio Technica ATH-MSR7GM and I have a MSI z97 Gaming 3 motherboard. In this article, we will delve into the characteristics of 150-ohm headphones and examine whether they truly benefit from dedicated headphone amplification. To find out if a dedicated headphone amplifier would be an improvement over your existing headphone output, we need to get a better understanding of the interplay between headphone and the output stage driving it. Most in-ear headphones are high to very high in sensitivity. May 27, 2024 · An amplifier serves to amplify the audio signal, providing more power and driving force to the headphones or speakers. Headphones that normally fall in this range are DJ and studio headphones. TLDR: Use Watts Law on advertised headphone specs to compare against your headphones impedance to get an idea of the power you’ll be getting before you buy the amp. Discover the Best Audiophile Headphones that Don't Need an Amp and take your music experience to a whole new level. 5W in 600 Ohm = about 15Vrms. In this article, we’ll delve into the world of impedance, power distribution, and speaker efficiency to help you make an informed decision. need one. A lot of studio headphones have been growing in popularity due to their superior quality over gaming headphones, and a lot of people stay away from them due to the necessity of buying an external amp to power some of these badboys. You could plug into it an impedance as high as you wish. If you mainly use headphones with high-end, professional audio equipment (headphone amplifiers, audio interfaces, etc) you might look for headphones with higher impedance (more than 100 ohms). 1. Do you NEED a headphone amp to power your headphones?My social media: https://twitter. if the headphone impedance is 32 Ohms, the amp's impedance should be no more than 4 Ohms), notably in the low frequencies. Once you start using headphones that are like 150 ohm, then that's when I'll consider an AMP/DAC combo. But alongside that purchase, many audiophiles wonder: Do you really need a headphone amplifier to make the most of premium headphones? The answer isn’t a simple yes or no—it depends on factors like impedance, sensitivity, and your audio Feb 2, 2020 · I have an Asus b85m-e/csm motherboard that uses onboard audio Realtek ALC887-VD. Headphones with a 150-ohm impedance rating often raise questions among audio enthusiasts about whether they require additional amplification to deliver optimal performance. One question that often emerges is whether 80-ohm headphones demand the use of a headphone amplifier. Nov 10, 2024 · When Do You Really Need a Headphone Amplifier? Not all headphones require an amplifier to sound great. What's the sensitivity on the headphones? Jul 22, 2023 · The AKG K240 Studio is a prime example. When looking for headphones, how high of the impedance of ohms do I start looking at AMP/DAC for my headphone? Do I need one if the headphone have 50 ohms? What about headphones with 150 ohms like HD 58X, do I Oct 6, 2025 · You see, headphone amplifiers boast performance-first audio circuitry and have been designed primarily to do one thing: to squeeze every ounce of sonic ability out of the headphones plugged into them. Your 2275 will work with the Beyers, Aug 30, 2023 · The world of headphones presents a diverse array of choices, each with its unique specifications and requirements. However, do you need a headphone amp? Find out more. Aug 24, 2024 · To fully utilize the potential of 250 ohm headphones, it is highly recommended to use an amplifier. But then, how do I know how much mW the amp is giving at the headphone's impedance? Most amp specs just show mW at 32Ohm etc. Feb 29, 2020 · Calculate the voltage output of the amp: 220mW (16Ω) = 1. How do I know if my amplifier is powerful enough for my headphones? If you Sep 11, 2023 · Don't settle for average audio quality. Bluetooth headphones obviously don’t need an external amplifier because they have one built in, but some Bluetooth headphones also have a wired option. It should be easy enough to achieve the desired volume level. While low impedance headphones may function without an amp, using one can significantly enhance the audio experience. If you To simplify all this, it's common to specify the maximum output of a headphone amp in volts, at two different load impedances, like 150 ohms and 32 ohms. However, this is debated and there may be exceptions to the rule. 96V Voltage should rise slightly, if at all, with more ohms in the load, as it did above. It’s the higher-impedance headphones (over 100 ohms) that often benefit from a dedicated amplifier’s extra power. By the end, you’ll be equipped to find the perfect amp for your headphones, listening habits, and budget. May 17, 2019 · Hi Guys, i have a question to ask I have an (asus rog maximus x hero wi fi ac z370) Motherboard and i'am planning to buy a (Beyerdynamic DT 990 PRO 250ohm) Would i need an external amp to get the full potential of the headphones ? Apr 5, 2024 · I need to add a headphone amp to my vinyl system and this is the way to do it. With an amp, you will experience a more complete sound profile and be able to use the headphones at a louder volume. Since tube amps can have output impedance that’s 5, 10, 20, or more ohms, having headphones with high impedance allows you to use those amps and maintain a proper damping factor. 48 ohms is not bad and should not need an amp in most cases if the sensitivity is good but if the sensitivity is low then you would. Feb 24, 2019 · Do you mean the HD595 ? As far as I know it is 50 Ohm. High end headphones are now affordable and designed with unique features for audio production. 6X gain with 16 ohm headphones. Low-impedance headphones (typically under 32 ohms) usually work fine with your phone, laptop, or computer. Feb 13, 2021 · So if your headphones have less than 25 Ohms of impedance, you don’t need an amp, the higher up you go from that number the more crucial an amp becomes. High impedance headphones require more power, usually from an external amp, to work properly and can even benefit from higher voltages. There are many other considerations to properly powering your gear, so as you upgrade into more demanding headphones, you might need more powerful equipment. Mar 18, 2017 · I doubt your device will be damaged because of higher ohms. Jan 5, 2019 · No, you do not need an amp for it. An external headphone amp would likely refine performance of the headphones, since GENERALLY, the built in headphone amps are not that great. Jul 15, 2022 · A headphone amplifier can improve the quality of audio output from your headphone. you probably came across an Jul 11, 2022 · Are you considering buying professional-grade headphones? Have you bought 250-ohm or 600-ohm Headphones and realized that you might need an amp? There are two basic reasons why you might want to consider buying a dedicated headphone amplifier: getting more volume and/or getting better sound. Output impedance should ideally be 1/8th of headphone impedance. It allows for better control over Just follow these steps: Enter the impedance of your headphones (measured in Ohms, usually found in the specs sheet). 35V), the any line out that's 2V would be to much for them so I hope you can dial it down. But all else being equal higher impedance headphones are harder to drive. Dec 12, 2017 · a good headphone amp may not be "truly necessary" in this case, but it would be a good idea 600-ohms is the old "professional standard" for recording studio headphones, where the amps are required to drive multiple sets of headphones at very loud levels for many hours at a time. The grand goal is to get high quality headphone audio from my PS5 to my 150 ohms headphones. A popular make is Beyerdynamic DT 770 Pro 80 ohm available at Audio 46 Beyerdynamic Shop or Amazon for $199. Get the headphone sensitivity (you don't have that number above): Let's say the sensitivity is 100dB/mw and 150 ohm Compare the calculated voltage output with the "voltage needed" below. This will ensure that your headphones can handle the high-quality input and deliver a more detailed and accurate sound. The signal might be soft and lacking in clarity, even with the volume turned way up. Some people drive the 250 Ohm Beyers just fine from their onboard sound, but you could look at the FiiO E10K for a nice and affordable DAC/amp combo. My question is; is there any reason to buy a dedicated amp over a motherboard like mine? Would there be a noticable difference or none at all? By the way, before this gets removed, I Jan 28, 2022 · For 250 ohm headphones like Beyerdynamic, you need a 31-ohm amplifier. This is another reason it’s important to know the output impedance. Headphone amplifiers can be small, portable and affordable, designed to be the middleman between your wired headphones and laptop or phone. A general rule of thumb is to consider amplifiers that have an impedance that is eight times lower than your headphones. A high impedance headphone is actually going to sound very good from a stereo amp, even ones with lower noise floors as the high impedance raises the noise floor a lot. Mar 26, 2025 · Investing in high-end headphones is a serious commitment, especially if you’re looking for superior sound quality and an immersive listening experience. According to this chart you would need 63 mW to drive the 880 with 600 Ohms with max output. I have the Shanling M2X and it has no trouble driving the 300 ohm HD6XX/650 and the 150 ohm HD660S with it. Jul 7, 2022 · An amp is essential to most 80 Ohm headphones. Sep 11, 2023 · Fiio FT3 One of Fiio’s rare headphones is made for studio monitoring, and features an impedance of 350 Ohms. If anything, your headphones are less likely to be damaged because of high impedance. I also owned an HD 599, didn't need an amp. A powerful portable DAC/Amp should still be enough, but a desktop unit is more ideal. Apr 4, 2022 · Sensitive (100 dB+), low impedance (8-32 ohm) headphones will typically pair well with a portable source (such as a phone) without much benefit from a separate amplifier. Many budget amps will say "Supports headphones 32-300 ohms" not because its strictly accurate, but because its what consumers are looking for, and unfortunately it tells you little about the actual capability of the amp. Dec 3, 2024 · You only need an amplifier when your source’s maximum electrical output through the headphone jack—whether it’s a smartphone, laptop, or something else—is lower than what your headphones require to reach the output level you want. Oct 10, 2023 · Headphones come in various shapes, sizes, and specifications, and one of the critical factors that can influence their performance is impedance. When the 16-50Ohm tap is used there will be max 6V = 60mW in 600 Ohm In S. So I am using my monitor's 3. when set to this tap. At 55 Ohms and 91dB of Sensitivity, they absolutely require an amp to sound loud enough. Otherwise, you can drive them sufficiently from pretty much anything, including a smartphone. There are two basic reasons why you might want to consider buying a dedicated headphone amplifier: getting more volume and/or getting better sound. One of the most popular offers has been the Beyer Dynamic DT 990 Pro (250 Ohm), and in a lot of places most people will recommend you external amps starting at 100 As the title says, my motherboard (ASUS Z170 PRO GAMING) claims to have good audio specs. Here you can ask which headphone is better, which amp you should buy, which gear best fit your budget and anything related to headphone comparisons and purchasing. vcog8 7t8uae ncar qm8r 89yyzk jvrfh6n 3ds iopsi3o 9ihkf vae4c