Douk Audio L1 Mini Stereo Line Level Booster Amplifier Audio Preamp with 20dB Gain and Volume Control

DOUK LI AUDIO BOOSTER: NEAT GADGET! I have a very nice, $600-ish Denon turntable with a good cartridge and quality built-in preamp. Since an upgrade to an elliptical stylus, the tracking and sound ed even further, but the volume was rather insufficient through my mid-power receiver (integrated amplifier plus tuner), particularly on softer recordings. The phonograph output simply wasn't comparable to that of the other components. I wanted to continue using the record player's own preamp due to its RIAA-compliant equalization, but it needed just a mild... boost! Too much of a boost (such as that from a typical phono preamp) would have either introduced distortion or forced the need to bypass the phono's built-in preamp altogether. That would have introduced a whole new set of concerns. // Enter the little "Douk Audio L1 Mini, Stereo Line-Level Level Booster Preamp." It boosts the preamp gain just a hair, no more than 20 dB. There is no tone coloration, no distortion, just the smallest signal boost needed ahead of the receiver. I get bigger, broader, full-range phono sound without the unsafe need to overdrive the amplifier. // Now, the features and limitations: Clean signal boost? Yes. / Flexible usage? Yes, as indicated. / Loss or change of sound quality? No. Only clear, increased volume. No tone controls. / Standalone preamp or amplifier? No, it's simply a preamp booster. / Is it a Bluetooth transmitter or receiver? No, its wired system offers better sound quality than Bluetooth. / Are cables included? Yes, audio cables and power cable are included. It is advertised as not including the power cable, but it does. Just plug it in and use it! / Bulky addition? No, very small and simple to use, but effective. / Expensive? No. For what it does and how well it performs, the price is a steal. // Overall, very nicely done, Douk Audio!

This product does exactly what it says it does, it will boost your audio line signal by around 20 decibels. My own measurement put this at 17.2 DB louder from 15 feet away before you start to get distortion. It can go up to around 19 DB or so but you get distortion. Even 15 db is plenty to make a stock stereo in a car really loud, but be warned you won't be pumping mass bass as the power output isn't there to drive your Fosgate 12s for example, obviously anyone installing quality equipment like that won't be using this thing. The product is cheap and has multiple inputs and outputs available (see pro tips below). It also comes with a USB-A power cable so you'll need a USB-A port available or otherwise supply your own power. Many of the complaints about this product seem to be curable but do require extra work and or parts. Pro Tips on how to get this to work great: 1. Take into account where you will be installing this. If you are installing this around unshielded cable, high voltage etc, because of its cheap nature, it will pick up a hum, this thing is not insulated at all really. It is best to keep it away from other devices and power it cleanly off a dedicated USB or power supply. See below for ideas how to fix if you get a hum. 2. The 3.5MM input will be priority and no other inputs will work at the same time if you use the 3.5MM input, however, if you use RCAs and the 5-Din this thing will take in both and mix them evenly (There is no way to to mix or boost one more than the other). The output is both 5-Din and RCA, you can use either or both at the same time. 3. Since this thing isn't driving that much power, I found even the cheapest cables work fine. Normally you want to use higher quality cables for the best sound with the least leakage but in this case we are going cheap, so even cheap cables will work. 4. If you are installing this in a car, you're probably like me and installing it on an old or stock in-dash stereo and those are horrible for grounding and will usually pick up a hum because of ground issues so here is: How to fix the dreaded hum that people complain about: First, you can try to ground your stereo better if you can. This can help, but if you are just hoping to plug it in and not mess around try a Ground Loop Isolator like this: https://www.amazon.com/dp/B06XQYN77L?psc=1&ref=ppx_yo2ov_dt_b_product_details The linked isolator uses the 3.5MM input on the amp and takes in a 3.5MM connection. An over simplified explanation is that by using an inductor that then creates a magnetic field, a ground loop isolator can essentially force any differences in current (caused by a bad or different resistance ground) to be nullified because this is what causes the hum. Please realize you'll need to get the correct kind of isolator for your inputs and outputs. Just search Ground Loop Isolator here on amazon and you'll find many. Since this isn't putting out that much power, cheap ones usually do the trick. Also keep in mind that there are two schools of thought and which one works for you depends on your situation: 1. Place the isolator between the head unit (a stereo for example) and the amp. In other words place the isolator on the input side of this amp. This is the typical way of doing things and works for the vast majority of cases in car audio although not all. 2. Place the isolator after the amp but right before the speakers if there are other components in the system like a game console, or another stereo component etc. This case is more specialized but you can pick up hum caused by the amplifier itself and it bleeds on the output side but this is less likely. The amp usually get's hum fed into it and you can eliminate that on the input side and the amp will output a clean signal. 3. Place an isolator on the input AND the output side. This is really rare and only happens in extreme instances where there are a lot of electronics at play causing problems for one another OR there are powered devices after the amp that are picking up hum from the combination of sources. In this case you'd add one on the input side as close to the amp as possible, and then one on the output side as close the speakers as possible. Good luck! This thing is a steal at the price for what you can do with it using a little know how.

I purchased this item to use between my componet CD player and a Stereo Tube Power Amplifier. Because my componet Preamplifier is awaiting shipment of a new power switch. I thought this would be a good inturn solution allowing me to still listen to my CDs. The not so good. The unit has a set of RCA inputs and a stereo 3.5mm input jack. The signal chain goes from the RCA jacks through the 3.5mm input jack. Unfortunately the RCA jacks did'n't work on my unit meaning the internal contacts in the jack were not connecting properly. The 3.5mm jack did work and with the proper adapter cable and I was able to get it working in my system. It is a pretty cool little device. I did remove the covers to investigate the problem. I was surprised to see this. It will run from single 5Vdc USB power supply. Inside the unit is a small power inverter that takes that 5Vdc and generates a +/- 12Vdc isolated power supply to power the NE5532 Dual OpAmp. It provides 20 db of gain ( voltage gain of 10). It has a slight rolloff of -3db @40Hz which is not quite ideal. Otherwise the unit has excellent fidelity and for my purpose it works fine.

Work fine but only lasted about a year and now all I hear is a hum sound. Tried switching out cables and jacks but it didn’t help.

Has Done An Excellent Job EVERY DAY For The Last 2.5 Years For My Office Stereo Setup With ZERO Problems. I use it just about everyday. For the last 15 years I've had The Logitech Z623 2.1 THX 330watts RMS System with Two 3'' Satellite Speakers and a 7'' Subwoofer that everyone swears is a 10" Sub, it's really impressive and would recommend it to anyone. I can hear it booming and pounding hard clear across the street but that's a whole different story. I just purchased a brand new LOGI Z623 about 6 months ago as the Subwoofer finally started to go out. I also have a Sound Bar above my monitor mounted to the wall. I had to split the Audio with and a 3.5mm Audio Splitter so the audio signal reaching each of the Speaker Setups which are The Logitech System and The Sound Bar, the audio signal is cut in half by the time it reaches them. This reduces or cuts the overall volume signal to each audio component by 50%. Everything was still nice and loud for the most part but the volume would frequently be at 100% to listen to my music which i listen to loudly. Many times it just wasn't enough though, i needed more- It was "almost but no quite" so I bought this Signal Amplifier and WOW! what a difference it made. My System is Super Loud Now. Louder than it ever has been. I'm getting every last bit of audio sound i want and then there's dump truck load more behind it - i just make sure to not turn it up too loud bc I could blow all of these speakers very easily and quickly. I never turn my system up to 100% bc i'd destroy it with this Singnal Amplifier and remember, My Audio Signal is already cut in half so this thing Amps the signal EXTREMELY WELL. The PreAmp Signal Booster has been doing a great job day in and day out. Sound Quality is great too. It's just nice to have all the sound i want when i want it. This is one of those purchases that i don't think about very often bc it's tucked away but when i think about it - it's one of the best purchases i've ever made. It's made in China so you never know what you're going to get but going on 3 years of nearly daily use and i would even say punishment bc i push it hard and it's held up well. So yeah, i'd recommend this as it's built well and built to last. It has a sturdy and solid construction.

"Mini Stereo Line Level Booster Amplifier Audio Preamp 20dB Gain Volume Control" fulfills every word of its title! Construction and finish are fine. As a preamp, it easily makes it into "hifi" performance. Maximum gain was about 20 dB. Measured performance using RightMark Audio Analyzer indicates 20-20k Hz frequency response that is very flat in the high end and rolls off gradually to -2 dB on the low end. Dynamic range is excellent, -93dBA. Total harmonic distortion is miniscule at 0.002 %, while intermodulation distortion measures 0.01%. These were measured using an ASUS/Xonar sound card and some of the specs are close to the sound card's limits. The only limitation that I see that could occur in some cases is that the output impedance is 100 kohms. If it is feeding an amplifier with low-ish input impedance, the audio performance could be degraded. Make no mistake: this is not capable of driving headphones, unless a headphone amplifier follows it to provide the required drive energy. The unit comes with a USB cable that can be used to provide +5 V power from a laptop or a cheap power adapter such as that used for charging many battery-operated devices. I haven't tested it with any other power supply, though it claims to be able to use anything from 5-20 VDC. Highly recommended to fulfill the need for boosting a line-level signal.

Here is my application for this little amplifier: We are doing a Christmas program with preschool children up on a stage. I play their music from my ipad through bluetooth to 2 linked karaoke-type powered speakers up on the stage. I also have a bluetooth microphone, which has a receiver that plus into the aux line-in of one of the speakers. The problem is, whether using these bluetooth mics or wired mics (I've tried both), the microphone level on this speaker is not nearly loud enough. (The music can get MUCH louder than the mic.) So, I bought this to raise the mic volume. I am running the bluetooth receiver (for the bluetooth microphone) into this preamp, and then run a cable out of the preamp to plug into the 1/8" aux of the powered speaker. It boosts the volume quite well and I no longer have to speak really loudly while "eating" the microphone. Yay! However, using the supplied cable (1/8" to white and red RCA) I got a whole lot of noise. When I switched and used one of my own cables, it worked just fine, nice and quiet. Either I got a bad cable, or it was a fluke of some sort. But the main thing was that I got everything to work well today, and I hope when I go back tomorrow it will all still work fine. (I've had plenty of experience through the years of technology that works and then decides not to work the next day, so I'm still kind of holding my breath, haha. But so far so good.) So far, it has turned out to be just what I needed!!

This preamp does exactly what it says it will and it sounds amazing. I am easily able to set my gain structure and this little dude helps me get the input level to where it needs to be when it hits my amps input. I've used it a couple times with a pair of Sony WH- 1000XM4 headphones and it sounded great. Next I am going to try it in my car right after the head unit and see how it does when feeding a jbl stadium 4 with 4 jbl 962M 6x9s on the outputs. The only negative mark I can give is that the inputs and outputs are not on the sife of the unit. I prefer hiding the wires but cannot with this preamp. Other than that small issue, it is perfect. Now if they could make one with 8 inputs, seperate volume controls and a digital display showing the power being pushed through it, then it would be even better.

今回の商品は、非常に良い中古品との評価だった。少し前に同製品を新品購入したが、不具合があって返品した。中古品として価格が下がり、非常に良いとの評価で出品されていたので購入したものの、送られてきた商品は前回返品した商品そのものであった。製品箱もなく、あり合わせの段ボールの小箱に入れれれていたので、開封した時点ですぐに分かった。箱には数字の「17」がマジック書きされていた。前回のものと全く同様。返品商品を「非常に良い」と評価し、再販するのはいかがなものだろうか、、、？？？

It did the job for Me boosted the signal to almost double the strength only problem is is that it introduces a little bit of white noise, but to be honest, I have an art clean box pro and that was introducing white noise as well, so it might not be this product. It might just be my amplifier regardless of that. I have a wireless RCA transmitter and I put this before the transmitter so the wireless signal completely cut out the white noise if anyone is running into that issue try to go wireless you lose a little bit of signal when you go wireless, but this boostsit right back up anyway anyways

This is a little dynamo. Installed between tv and amp. The improvement to the volume and sound quality is fantastic. I have tried many other similar items for a much higher value and they are nowhere near as good as this. Very happy

I took the plunge on this thanks to the review from coolspot, as I wasn't convinced that weren't cheaper options out there. While I can't speak to the sound quality yet (which I will review at a later point) due to only boosting LFE frequencies, it certainly does the job at boosting the signal. Setup is as follows. Receiver > 10-15' rca cable > Booster > SoundTech ST300CX (crossover unit) > Yorkville A4.4 > Aura AST-2B-4 Pro Bass Shaker. Before, I had to have the dial at about 3-4 o'clock (80% volume) to get a usable signal to the shaker (which is one of the most easy to feed ones out there). Now I just have the pre-amp at 12 o'clock (50%) and the power amp at 9 o'clock (maybe about 25%). So yeah, this is a great win! I have not experimented to see how much loss is caused by the long RCA cable I've been using this whole time, but that's irrelevant to the performance of this little USB powered unit right now. I look forward to testing to see if this has a hard cut off at 20hz, or if it can boost signals lower than that for my Buttkicker.

used it to boost line output for kawai digital piano bang for your buck amazing with little or no distortion