Audio Concepts electrical engineering General

What’s the best rechargeble battery for guitar and bass?

Active guitar pickups (which includes piezo pickups) and all analog musical circuitry benefits from higher voltage. (The benefit is increased headroom). A fresh, regular “AA” battery produces 1.5 volts and that decreases as it loses its charge down to 1 volt where the device stops working. So, in general, if you’re about to record with regular batteries you’ll want to have a fresh charge to maximize headroom.

Unfortunately the “good” rechargeable batteries (NiMh) produce less than that: 1.2 volts. This means they will have less headroom. BUT as the battery runs out of charge it stays more consistent than the regular batteries

Conversely Alkaline rechargeable batteries start out at 1.5V when they are fresh and behave like the disposable ones .. they gradually fade down to 1 volt where the guitar pickup stops producing sound. So while they start at the right voltage they do wind up averaging somewhere close to 1.2%

This means if you are recording in a high-fidelity situation use the alkaline batteries but have a charger close at hand and swap them out very frequently and you’ll be better off than using disposable batteries. But if you’re on the road, and want more convenience then use the more-popular NiMh type.

Keep this in mind if you want to reap the benefits of the alkaline battery: Once an alkaline has used a third of its charge it is producing 1.2V just like the NiCh battery. Then it drops fast so if you want have the benefits of an alkaline battery you’ll have to keep it 75%+ charged. If you have a battery health indicator, that would usually mean when it drops from full to almost-full.

I found this great video that tests NiMh batteries (spoiler alert, Duracell and Ikea’s rechargeable “AA” batteries completely outperform all of the other brands).

Some other info — “AAA” “C” and “D” batteries all operate at 1.5V! they just have different capacities

Alkaline (Manganese-dioxide) and Zinc-Carbon are primary cells that start out with 1.5 volts and then fade down to 1 volt

NiMh is a secondary cell which gives it a nice and even curve. Here is an image showing this:


So if you’d like to get the absolute best fidelity from your recordings, go alkaline! and if you just want to play music and have a more reliable setup go with a Duracell rechargeable battery

(No sponsorship here, though I’ll probably set up an affiliate link in the future when I’m not feeling so lazy after researching this!)


A List of the fanciest Analog-to-Digital converters

While the best analog-to-digital converter (or “ADC”) is different for everyone here is a list of the most worthy contenders (and thus brands) on the market today.

But first some advice: if you are planning to track your converter is probably not the weakest link in your recording setup. The room is more important than the microphone, which is more important than the preamp, which is more important than the converter. Just about all modern converters have extremely low noise floors and are generally suitable for most people’s needs. The law of decreasing returns in audio gear.

If one is say, looking to master or sweeten an already-recorded digital signal then investing in a really good ADC (and DAC – digital-to-analog converter) could be more practical.

However the best converters can do things like create a more defined sense of space, or make someone who isn’t a critical listener notice the difference between preamps. If you do tracking (recording) and have a great room+mic+preamp then you might want to invest in one of these ADCs

Clocking is really important to analog-to-digital conversion creating a better image to my ears in conversion shootouts. better clocking can also have a clarity to particularly the low frequencies in my experience. Having a really nice internal clock is important for tracking as analog-to-digital clocking cannot be improved by jitter rejection like with digital-to-analog conversion.

With that said upgrading a converter with an external clock can can have a positive impact on the performance of the converter if the external clock is better and the connection between hardware units is good.

There hasn’t been as much development of ADC microchips as with the DAC chips over the past 20 years so most of the modern technology is focused on getting a better signal to the chips

The analog side of the converter has a huge impact on the sound much like the sound of the analog side of a tape recorder gives the timbre of what many would call a “tape” sound. Class A or passive seems to be a trend among the best-sounding converters but there are many creative ways they have been made.

Latency is also a big factor with audio conversion when tracking. The Lavry Gold is a very highly-regarded converter however it has 8ms of latency, and that’s before the interface and DAW introduce their own latencies. This may disrupt a musician’s timing, for example. Personally I prefer under 2ms total latency to be ideal for tracking. Many will be ok with 5 milliseconds (in Pro Tools that’s 256 samples for 44.1-48khz, 512 samples for 88.2-96khz, and 1024 samples for 176.4-192khz). Sound travels at about 1.13 feet per millisecond so if a guitar player is used to playing with their amp across the room 8ms might be totally fine for them, or even feel natural. Likewise a drummer is practically inside their kit so a total latency of 2ms would sound natural

There is no “best” converter but here’s a list and some details to help you decide which to shoot out.

This page is an ongoing project, please let me know if your converter is not included (and should be!)

Acousencesystem 193 – Here is a shootout that makes this a pretty clear winner from those involved. My 2nd favorite is the Lake People (which is much less expensive) *


2192 – Tape OP, Sound On Sound
X16 – While much cheaper than most on this list the Apollo X16 has extremely high specs. While specs do not make a converter it is worth noting that the X16 has some really desirable numbers in comparison to many other converters on the market.
Dynamic Range: 124 dB (A-weighted), THD+N: -115 dB (0.00018%), Frequency Response: 20 Hz – 20 kHz, ±0.05 dB

Antelope Pure2

Avid MODDED – Black Lion Audio does a mod that drastically improves the quality

Benchmark – ADC16


Burl – B2 Bomber and Mothership – These are designed to add a bit of analog mojo to a signal. If driven hard more of that quality is imparted on the sound. While “colored” they are still a converter, not a preamp or microphone, so it is a more subtle difference.

Crane Song HEDD

Crookwood MultiDAD

Digital Audio Denmark

Dangerous AD+

dCS – 905 – discontinued – Class A

Direct Out Andiamo

emmLabs DAC – Meitner ADC8 MK IV – Class A

Euphonix – some color,


Blue – AD 245 – 1
Rednet 1

Forssell – MADC-2 and MADC-4 – There is no shortage of raving reviews on these units (along with the MADA-2a which is ADDA). In one thread it is reviewed as both wonderful but that it lacks soft-limiting. Some have said the DA section is where this unit really shines. This unit seems to win a lot of shootouts.

Greg Hanks Design BA-AD660

Grimm – AD1 – discontinued – Discrete, Class A – DSD converter

iZ Radar Nyquiste Frame

AD8 *
Audio LATTEClean/transparent, maybe a little smooth, max sample rate 192khz, <.01 ms total latency A/D section @ 192k, +27.5dBu max output level into 600Ω,


Lavry (gold and blue)
Gold – Has a sound. Has amazing ‘soft clipping’ to crank the gain while mastering. Conversely not exactly high-headroom compared to some modern converters. Very old while converters advanced rapidly in the 2010’s however there could be benefits too. The Most desirable version is the MKII model not the current MKIII because some components could no longer be sourced, Some like the older versions more 8ms latency from internal processing. Lavry uses its own converter chips: “Lavry uses successive approximation ADCs as opposed to Delta Sigma ADCs wich are standard in most other products. This is a fundamentally different conversion process and the main reason why the Gold AD sounds the way it does.Here are some well-formed thoughts about the Lavry Gold vs Prism ADA-8XR. Class A.
Blue – Integrated circuit, also has a sound, old but some might still prefer it to some other items on this list. Items on the circuit board are not as high-end as what is found on the gold as well as a switching power supply but it was designed as a lower-cost alternative.

Lake People
ADC F444 – The linked version, the F444D has 4 channels. Very affordable and perfectly natural and smooth. The imaging is less etched out than Mytek’s Some Advice about how to use Lake People converters Another view
ADC RS04 *

Lynx Hilo – Great RTA meter

Lucid Technologies ADA 8824

Pacific MicrosonicsModel Two – This is a legendary unit made in the 90’s There were only 100 made, but they have a reputation of being “cooler than reality” but in a convincing way. They are still loved. Perhaps because microprocessor voltages were so much higher than they are now (because our processors now are so much more efficient. Today’s processors have transistors that are 5nm and even smaller,

ADA-8XR“Bouncy” low-end, lots of headroom. “Relaxed” These converters have been very highly regarded for a long time but are now aging and while still regarded as excellent the price tag of other converters of high quality has dropped significantly.
Titan – Strong reputation but across a wide range of ears the ADA-8XR wins out often. Debate below!

Merging TechnologiesHapi and Horus (Horus is bigger with more options but the same quality)

Metric Halo LIO-8 3d

MSB Technologie ADC V

Brooklyn ADC – 2 channels
8×192 ADDA 8in 8out but not quite as nice as the Brooklyn

Nagra VI Music – While this is designed as a field recorder the conversion is quite good

QES Labs – PAD-2 – transparent/clean, maintains space very well

RME ADI-8 QS – excellent drivers/low latency but not known as a ‘top-end’ converter

Sound Designs – what do you think of the conversion?

Sound Performance Lab: SPL MadisonReally good, and 16 channels


StageTec Truematch XAD+


Weiss ADC2


Black Lion Audio – Their AVID HD I/O and 192 mods have a really good reputation.

USB and Thunderbolt honorable mentions

Ayre Acoustics – QA-9

Build your own!

Texas Instruments – PCM4222 Evaluation Module (EVM)

Other converters that are not “High end” but are worth considering:

Aphex, Art, Audient, Black Lion Audio Drawmer, Focusrite, Fostex, Klark Teknik, MOTU, PreSonus, Sonifex, Tascam

More thoughts about conversion

Each neuron hears once every 1 millisecond so if a conversion process can happen within 1ms from A to D to A again then it will be imperceptible by the artist in terms of musical performance

Higher bitrates reproduce/record a wider frequency range and it can be argued that it has an effect on the overall tambre of the audio at high SPL’s. At 100dB this could have an audible difference but it would be so subtle that the shaking of the room at that loudness would have more of an effect in most places.

Audio Concepts General

What is a Class A Discrete Mic preamp?

Let’s break down each part of this: “class A” is a type of amplifier circuit that reproduces the whole audio signal. This is different than a “class B” amplifier which only produces the top or bottom of the sound wave. class B amplifiers are used two-at-a-time so one reproduces the top while the other reproduces the bottom. Class A has the highest fidelity reproducing both together because there is no “crossover distortion” or, more simply put, imperfections when joining the top and the bottom signal from the class B style circuit. The negative about a class A circuit is that it uses much more power and thus creates more heat.

“Discrete” that means that the primary circuit for the mic pre uses individual components that are selected for the best combination from the point of view of the designer (the components are seperate, or “discrete”). For example a tube, op-amp, or transistor are examples of a discrete components found in a mic preamplifier. Alternatively an integrated circuit (“IC”), or “microchip”, is a small package that contains a very dense layout of semiconductor components.

There is a deeper meaning to whether a mic pre, compressor, or converter is class A and what that means to you, the purchaser: A class-A, discrete piece of gear was most likely designed to be higher-end with less compromise than the average integrated circuit design. Though, a poor design can still be marketed as “class A, discrete” because a popular thought is that to be of a certain quality a microphone preamp must be both class-A and discrete. That is a myth.

There are preamplifiers that are considered among the best that break one or both of these rules.

Let’s take Rupert Neve for example. His design for the Neve 1081 is not class-A, it is class-AB yet it is considered one of the very best preamps of all time.

My Grace Designs Model 101 (ribbon version) is a distinctly clear-sounding preamp that is wonderful for its fast transient response, meaning it catches a more accurate representation of the sound wave, particularly the leading edges of a sound. But it is not a discrete design but rather an integrated circuit.

It all comes down to the designer and the design they they make. With that said one can often generalize that truly discrete and class-A piece of audio gear will sound good because of the effort it takes to make one.

This is because while it is more costly and difficult to build a preamp with discrete components it is also often an indication of quality as it reflects on the designer’s intention to achieve a performance goal regardless of cost. If trying to create a really nice-sounding preamp it is easier for many electrical engineers to select and optimize components than having to build a dedicated integrated circuit chip since creating a custom chip requires a lot of resources and work in comparison. Additionally most integrated circuits (read: the pre-made ones) cannot handle the voltages that discrete components can. A high voltage can be very beneficial to headroom, dynamics and frequency range. A clever designer like Grace Design can do amazing things with an purpose-built integrated circuit (with a higher voltage and bias than the average integrated circuit) but a microphone preamp is not a complicated circuit and usually those seeking this certain level of quality will go with discrete.

Let’s be mostly discrete

My own opinion is if the integrated circuit in the Grace Model 101 is specifically designed that kind of makes it a discrete component of sorts in the sense of the non-technical word, right? To me the important part of ‘discrete’ from the prospective of one who’s job is an intersection between physics and black magic is that everything that was picked to be specifically a part of a mic preamp. None of the components were designed to also do other things beyond their job in the chain of the analog audio amplification part of the preamp. If a chip can amplify but also check your email it’s not as focused. There will be less fidelity because it is not purpose-built, other parts of the circuit introduce noise, distortion, etc. WIth discrete (individual) components specifically selected all the components in the chain can do is is their part in amplifying the gain from mic-level to line-level along with whatever features were specifically designed into the preamp e.g. a low pass filter. Everything is there with a purpose.

One trend that stays very consistent is that discrete circuits are usually more expensive than integrated circuits. Another easy generalization is that integrated circuits are more easily (and commonly) smaller than discrete circuits.

For all of these reasons prosumer audio interfaces will usually have integrated circuits and high-end pro gear will usually be discrete/class-A which brings us to:

You’ve got A lot of Class

“Class-A” gear uses a single device (tube, FET, or transistor) to do the full swing through of the signal through both positive and negative. Class-AB and B use a separate amplifier device for the positive and for the negative.

In an audio waveform there are moments where the wave is above silence, below silence, and at silence. A class-B amplifier pushes the top of the wave up with one device on the circuit and pulls the trough of the wave down with a second device. A class-A amplifier uses just one device for the entire input signal (the conduction angle, or “Θ” equals 360°). Because it is both amplifying the positive and negative sides of the wave at the same time but the wave can only be either in the positive or the negative a class-A amplifier device must constantly dissipate ½ or more of its available output power as heat — meaning it is wasted.

Class-B and class-AB dual-devices (Θ = 180°) don’t have this issue, making them more efficient because it splits the sound wave into separate positive/negative (or top and bottom) parts and and uses a separate device for the positive and negative parts of the sound wave but the drawback here is there is a distortion created at the point of separation because one might have switched off before the other has switched on. Class AB circuits are biased so that both are on at this crossover point. The benefit here is that a class B or class AB circuit will be more efficient because with the two output devices reproducing the upper and lower waveforms are switched off when not in use and already use less power on top of that.

A class-D amplifier (found in many loudspeakers) uses a pulse-width modulation instead of directly using the input signal at all and is much more efficient yet retains less fidelity

A class-A design can be simpler than the rest because the concept itself is simpler, has generally better high-frequency performance (after all the higher frequency the wave crosses ‘0’ the more often there is distortion which runs into issues kinda related to the nyquist theory), reduced high-order and odd-order harmonics, no crossover distortion (and low distortion in general).

However class-A amplifiers are inefficient and rarely used outside of audio. The old studio consoles were filled with them and required a hefty power bill (but also doubled as heater). While glossing over a lot of technical points the power-inefficiency is essentially the reason a class-A amplifier has more headroom as well. But this means a more expensive power supply and better heat sink is required.

Class-A designs are more demanding on components and harder to design and build. But this also means that the components are of higher quality

You’ll find transformers in many audio devices as well and these can provide a passive (meaning no power-amplification) gain, can help match signals/impedence, and provide galvanic isolation between things. But a circuit might be advertised as ‘transformerless’ because transformers can potentially introduce phase shifts, can have a ‘sound’ if used in some ways, and can be large and heavy.

Tubes provide amplification and can give a tonal character but they can also be used in different parts of circuits and different ways to create very clean audio as well.

Here is more detail and some citations: gearslutz gearslutz gearslutz cakewalk forums power amplifier classes.

What makes a good preamp? That’s for another article but the short answer is a good designer.


Shure SM57 and SM58, predecessors, Beta 58 and more

“The 546 was a “high-end” version of a 545 that used a capsule selected for consistency. The SM56 and SM57 were originally sold as being non-reflective 546s. There was also a gold colored 546.” – Bob Olhsson (from Gearslutz)

Crimson Audio SM57 and SM58 Mods

Shure Unidyne III SM57 Search: Reverb

ZenPro modded SM58 SM57 Granelli-SM57 Transformerless-Passive-SM57 Granelli-Transformerless-SM57 (no phantom)


Line Level Inputs: The Difference Between +4 and -10 dBV

+4 dBu line inputs can handle a louder signal and have more headroom. They are found on high-end audio devices and increasingly more modern consumer devices. -10 dBV line inputs are the standard for consumer devices.

For many the question is what setting should be used on a device’s line output and that depends on what the destination line input is. The best case is to match, and many devices have a switch to go between +4 dBu and -10 dBV

If you must use hardware that doesn’t match then try to match the gain:

If you have a device with +4 output going into a -10 dBV line input
Turn the gain down on the output device or in software that controls the output until the input device isn’t giving any indication of clipping (and your ears don’t tell you it is clipping). Alternatively if your -10 dBV mixer/interface/etc has gain controls you can try lowering the gain. One solution could sound better depending on the specific devices you are using. The best solution might be a little attenuation on both sides The key problem to mitigate here is to prevent the input device from being overloaded and sounding bad.

If your device has a -10 dBV input(s)
The problem here is a raised noise floor due to the output being significantly below optimal the optimal line input level. You will receive a quiet signal. If the destination hardware has gain controls you can turn the gain up. This is the higher fidelity problem to have vs having a signal that is too hot.

The reason fancier gear has inputs that can handle a voltage of +4dBu is because when the gain is higher the noise floor is lower relatively. If a device has a switch then most likely same principle apples, the -10 dBV setting is usually an attinuation which brings the signal closer to the noise floor. Switches in some hardware might use gain to reach +4 dBu but that is both more expensive and more complicated circuitry (introducing another amp) and the input device may have better-sounding gain.

Conversely -10 dBV is more for consumer/budget electronics because they may not be able to handle a hotter signal

The Nitty Gritty

+4 dBu is 1.23 volts
0 dBu is .775 volts
-10 dBV is 0.3162 volts

+4 dBu is used as a reference because the 1.23 volts historically (from way back in the tube days) was enough voltage over the plate noise (about 20 dB for many tubes) that one still has good signal-to-noise ratio while still leaving enough room above to allow for peaks and generally normal audio operations.


A history of the detailed microphones (ELA M 251, U47, C12, M49/M50, U67)

The “Detailed Mics” are a class of five historic microphones that have a few special qualities.

The first being that they all have external power supplies instead of phantom power. This greatly increased the headroom because the boxes are not using phantom power which is limited to 48 volts. This is in part because phantom power did not exist yet! There are some modern microphones that use external power supplies like the Rode NTK, Chandler Limited, sE Electronics/Rupert Neve R1N1.

The second bit that makes them have that little extra is that while microphone technology hasn’t changed for many years the tools we have to make them has changed. Back in the 50’s the analysis, computer design, etc did not exist so they could not make the microphones using the same measurements we use today. As a result they had to fill-in the idiosyncrasies with good sound and flattery-of-subject. It’s not just the curve of the frequency spectrum —

Flying Sound’s long-body U47, #3072. Originally purchased by Radio Recorders Hollywood in 1954.

Telefunken/Neumann U47
This is the most well-known microphone in this group (and perhaps of all). It is known for its “Authoritative mid-range” and extended low-end response. The U47 FET is a cardioid-only U47 without the tube (to simplify) and is perhaps the best kick drum mic for the job in many cases. Neumann has started making the U47 FET again.

Neumann M49 #2001 (photo: Vintage King)

Neumann M 49
This microphone shares the same capsule with the U47 however has different electronics. It is a bit more ‘flat’ than the U47. This mic is often thought to be better for female vocals because the U47 can have a nasality-like quality on some voices

Neumann U76 (photo: geartechpro@eBay)

Neumann U67
This is the next in the generation of the Ux7 models and was designed as a close mic. Prince owned and used one to record himself. Neumann has resumed production. While the other mics in this list have a strong proximity effect the main difference here is that the proximity effect (strong bass tone when close to the mic) has been mitigated to allow closely talking/other souces to sound more natural. There are several versions of the U67 — the M269 is a U67 that uses the AC701 tube as in some ELA M 251’s. The SM69 is a dual-capsule version (stereo mic) of the M269. XY guitar mic anyone?

AKG C12 (photo: Vintage King)

The diaphragm on the C12 capsule is bright which makes this tube mic have a shimmering quality on strings that is very ear-catching. The C12 capsule was also used in early versions of the c414 mic. There is a dual version called the C24

Flying Sound’s Telefunken ELA M 251E. Built in 1959

Telefunken ELA M 251
AKG used Neumann’s U47 design as a starting point and combined it with the C12 capsule to create a bright-sounding (boost in the 10k range) microphone excellent on just about anything.


A way to get around iOS/iPhone’s annoying autoplay.

If you are like me and have your iPhone tethered to your car you will have noticed that iTunes likes to play the first song in your library when it forgets what you were doing last. Additionally the next few songs tend to be the same as well.

While I don’t know why they haven’t allowed the user to customize this or make it actually random I have a solution for you — this is a very long (but low quality Mp3) that will almost certainly appear in your library because of the name:




The Fogcutters in the studio

The Fogcutters recently recorded with us and made this video. We used all of our inputs for this session!


Live At The Studio Portland – The Other Bones

The Other Bones recently came to The Studio to do a live recording, check it out!




I am very proud to have helped out a little for this album! Way to go!


My nerd quest is complete

Here it is, the Telefunken ELA M 251

U47 on the left, ELA M 251E on the right and U87 center.
U47 on the left, ELA M 251E on the right and U87 center.

The capsule is original to the mic and the sound blows me away! It instantly became my go-to instrument mic because I feel like it gets me where I want to be without using plug-ins roughly half the time and is detailed and full-bandwidth. It has rounded out my mic closet in the way I’d hoped because it can make some people sound like a star but often the 47 is really good on a lead.

I’ve bitten the bug, I won’t be satisfied until I have a M50, C12, U67 to finish my collection of detailed mics. A pair of each, really.

Frankly, regarding any upcoming U67 purchase I would be more interested in finding a pair of SM69’s. It is the stereo version of the M269, which is the AC701 tube version of the U67. My ELAM has a 6072A tube, which I picked for various nerdy reasons, but it’d be nice to have an AC701 mic in-house, particularly in the form of a stereo U67.

Anyway, I nerdjest. Anyone who’s interested in seeing one of these in the flesh (or metal) please contact me. The only way I was able to play with these things was by buying them and I think you should get that chance too.

EDIT: If you are looking to sell any of these mics please let me know.


A new member of my family

I got an original Telefunken-branded U47. It’s got all of the trappings I wanted, the more recent capsule but original transformer and VF14 vacuum tube. It was Frank Sinatra’s favorite mic, he would sometimes refuse to use anything else. I’ve been told he called it “My Tele”.

Frank Sinatra singing into a U47
Frank Sinatra singing into a U47

Frank Sinatra later on with his own U47 from Capitol Records

It was also a favorite of George Martin for almost all Beatles vocals however he was using a U48 which is a U47 wired with a figure eight pattern instead of omni. This is because they were using wedges instead of headphones and were often tracking two vocals face-to-face to one mic.

The Beatles singing intoa U47
The Beatles with a U47 or 48

The one I found was originally purchased by Radio Recorders Hollywood in 1954. They were an early recording studio that recorded Frank who then later got his own from Capitol Records however the engineers at Radio Recorders got to pick through the VF14M tubes when they picked up the mics and it still remains in my mic to this day because the low voltage of the mic does not wear away the tube much at all. Also at that studio who may have used one of the four U47’s: Elvis, Billie Holiday, Charlie Parker, Louis Armstrong, Jimi Hendrix and more. There isn’t a way to tell which particular mic was used on which session, but the U47 would have been a star member of their collection and used liberally.