FAQ - Frequently Asked Questions

Q0: Do you sell through dealers?

A: No, because dealers would add 30-40% to the price. Said another way, you would pay a dealer at least 30% more for exactly the same items that we list on this website. The only way we can bring you the highest quality capsules, the custom circuit designs, the world-class DIY documentation at the prices we do, is by selling direct.

Q1: My microphone is broken. If I install a new capsule, will that fix it?

A: We never recommend modifying a broken microphone. Unless you are sure that your broken mic's capsule has failed, and further that nothing else in the mic is broken, the risk is high that the mic will continue to not work after a new capsule is installed.

Therefore, we recommend fixing the microphone first, before upgrading it.

There is one exception to the above advice: If you plan to replace both the circuit and capsule -- if, that is, you're using the broken mic just as a "donor body" -- then it makes great sense to start with a broken microphone.

Q2: Do you have any mods for my microphone?

A: First, see our directory of mic mods. If enough people have asked about the specific model that you have, they'll be listed in that collection.

If your mic is not listed in that collection, then we don't have ready-made upgrade recipes for you -- but we probably still have mods available. You would need to research the compatibility of our capsules and circuit kits yourself using the information on this site.

Mic mods belong to one of two categories: capsule upgrades, and circuit upgrades (and/or replacements). Read on to figure out if we have compatible choices for you.

About capsule upgrades

For the vast majority of large-diaphragm condenser microphones, we offer compatible capsule upgrades.

If you're looking for a K67 / K87 / K870 / K103 capsule, see the RK-87. If you're looking for a K47, see the RK-47. If you're looking for a CK-12, see our RK-12.

For a very long but hopefully comprehensive essay on how to choose a capsule for your mic, see our article, Introduction to Condenser Capsule Upgrades.

About circuit upgrades

We make multiple FET and tube circuit kits that might fit your microphone. To determine whether MicParts' circuit boards will physically fit and match the mounting holes of your chassis, scroll to the "Compatibility" section of our circuit kit product pages. E.g., click to see the MP-V57 and T-84 product pages, or find the rest of our many circuit upgrade kits here. In the "Compatibility" section of most of those pages, find the PCB outline drawing, and click it. If we have a dimensioned drawing available, clicking that outline image will download a PDF that shows the board dimensions. Print that document, cut out the paper template, and hold it up to your donor mic's chassis. Does it fit? Do the mounting holes line up? If so, then that circuit will fit your mic.

If your donor mic has external switches, they will not be supported by MicParts' circuit upgrade kits, unless specifically designed to do so -- which would be explained on the product page.

Q3: Do your capsules work in electret microphones?

A: Electret microphones require electret capsules, such as the TSB-2555.

Because electret microphones usually do not provide polarizing voltage to the capsule, our large-diaphragm models (RK-12, RK-47, RK-87) will not work there.

If you're not sure if your mic is an electret, research it at the RecordingHacks microphone database.

Q4: Which of your DIY microphone kits is easiest to build?

A: In order of difficulty, from least to most, we rank our products as follows:

  1. Capsule installation. If you're new to DIY audio, the easiest and biggest bang-for-the-buck mod is to install an RK-47 into one of the inexpensive transformerless microphones listed in our mic mods directory. See the MCA SP1, MXL 990, MXL V250 or 910 (when priced below $80), CAD GXL2200, etc.
  2. Studio Projects C1 EQ mod. (Also available for the C3.)
  3. T-25 DIY microphone kit. This is the easiest-to-build all-inclusive microphone kit we make. We introduced this in April, 2020.
  4. S-25 DIY microphone kit. This is our second-easiest-to-build microphone kit. Despite its low cost, the S-25 is in frequentuse in numerous commercial studios whose mic lockers include vintage AKG, Neumann, and Telefunken microphones.
  5. 990XF circuit kit
  6. T-series microphone kit, or T-84 Circuit Kit.
  7. T84-55 Circuit Kit
  8. S-12, S-47, S-87 DIY microphone kit, or MP-V57 Circuit Kit, or SDC Circuit Kit.
  9. V-251 tube microphone circuit kit
  10. S3-12, S3-47, S3-87 DIY microphone kit, or TL3 Circuit Kit.
  11. 12-251 tube microphone kit, or Fox 460 tube circuit kit.

In all cases, we strongly recommend that you learn how to solder first. Please do not risk expensive DIY audio components if you are not comfortable forming good solder joints.

Q5: Which of your kits is best for [male vocals | female vocals | rap vocals | acoustic guitar | etc ]?

A: See the Application Guide.

But please understand that these are guidelines only. Nearly any microphone can be used on nearly any source, depending on what sound you're going for.

Q6: What is the best microphone for rap? (or hip-hop, or folk, or metal, or bluegrass, etc)

A: In general, we do not find microphones to be genre-specific.

Take the Shure SM7B, a great all-around mic if you have a great preamp for it. It is a go-to choice for "screamo" metal vocals, but was also used for Michael Jackson's voice on Thriller. Is it a "metal" microphone? or a "pop" microphone? Yes and no to both; it's just a good microphone.

Our DIY mics can be, and indeed are used across a huge variety of sources, studios, and applications, from orchestra to voiceover, from thrash metal to classical guitar and everything in between.

Q7: What are the differences between the transformerless circuit kit and the transformer-coupled circuit kit?


Sonic differences

The transformer circuit has much more second harmonic distortion (aka coloration) than the transformerless circuit, due both to the operation of the JFET and to the transformer. 2nd Harmonic distortion is, in many applications, a welcome characteristic. It gives grit, weight, and authority to a track. Note that most vintage microphones do impart such coloration to their tracks, because most vintage microphones used transformers, whose sonic imperfections are usually perceived as a benefit.

The transformerless circuit has higher output, and is more likely to need a pad on moderate-volume sources.

Feature differences

The transformer circuit (T-84) has two internal switches, one for pattern (Cardioid/Omni) and one for pad. Both can be used independently.

The MP-V57 transformerless circuit has one switch, which can be used either for pattern (Cardioid/Omni) or for pad, but not both.

The 990 transformerless circuit has one switch, designed to be used only for pattern (Cardioid/Omni).

The TL3 transformerless circuit has two external switches. One is a 3-way pattern switch (Omni/Cardioid/Fig8), and the other is a pad. Both can be used independently, without opening the microphone.

All the transformerless circuits (990, TL3, MP-V57, SDC) can optionally be built with high-frequency corrective EQ to roll off the highs from the capsule. In the case of the TL3, the EQ capacitor is socketed, facilitating experimentation and per-session tuning.

Build differences

The transformer circuit (T-84) is easier to build than any of the transformerless options. It has a lower parts count, and a lower count of polarized parts. (Polarized parts must be installed in a specific orientation, matching positive and negative legs for example.)

Cost Differences

The transformer circuit costs more than the single- and two-pattern transformerless circuits, because making great custom-wound transformers is expensive.

The TL3 circuit is priced slightly higher than the T-84 circuit because it required a significant amount of R&D, and because the finished TL3 will go head to head with any 3-pattern FET mic on the market.

Q8: I broke a part in my kit. Can I get a replacement?

A: We have a flat fee for passive circuit components (resistors, capacitors, diodes, inductors): $12 for domestic US orders, including FedEx 2-day shipping, or $28 for international orders, including FedEx Priority shipping (limited to FedEx rate availability).

The flat fee does not cover circuit boards, tubes, transformers, capsules, switches, or microphone body parts. Contact us for pricing and availability of those parts.

Before requesting replacement parts, please inspect your kit to ensure that it is complete in every other respect.

The easiest way to initiate a replacement parts request is to send the appropriate amount via Paypal to the email address shown here. Include in the request:

  • A very specific description of the part(s) you need
  • The order date and email address of your kit purchase
  • Your complete and current shipping address

We cannot provide extras or spares beyond what is actually needed to complete the build.


Q9: The T-84 / T-series circuit kit includes a 3pF capacitor, but I received a 5pF capacitor. Do I need to replace this part?

A: The label actually says "3 ± .5pF". In other words, this is a 3pF capacitor, with an actual value between 2.5–3.5pF. It is not a 5pF capacitor.

Q10: What does it cost to ship my order to [ insert country here ]?

Shipping costs depend on package size, package weight, and shipping method. We offer many methods, from USPS "1st Class" (inexpensive, slow, unreliable) to overnight FedEx/UPS.

The only way to predict shipping costs is to put the item(s) in your cart and go through the checkout process. You can cancel the order after seeing the costs, before submitting payment information.

See our full Shipping Policies, especially regarding international deliveries.

Q11: Can you declare a lower value for exports?

If we did, we would be subjecting ourselves to possible civic and criminal penalties (read: fines and jail time). Falsifying export and customs documents is considered fraud. As much as we'd love to have your business, we're not willing to go to prison to earn it.

See our full International Shipping Policies.

Q12: What should I set my capsule voltage to?

Most of our transformerless kits include a trimmer that allows fine-tuning of capsule polarization voltage. The procedure for measuring and setting this value is included in the assembly manual. The following text explains in more detail what value to set.

Capsule polarization voltage in this circuit affects sensitivity in this way: sensitivity rises with voltage. Because circuit self-noise is constant (meaning: is independent of input level), raising capsule voltage improves the microphone's signal-to-noise ratio. Said another way, the effective noise floor of the mic goes down as capsule polarization voltage goes up.

However, when polarization voltage rises above 65V, the risk of diaphragm collapse increases, especially under high SPL or when the capsule is subjected to air blasts.

Therefore, we recommend setting capsule polarization voltage to 60VDC.

Q13: Can I send you my microphone for modification?

Please see our Mic Mod Service Policies page.

For business policies, please see our Terms and Conditions.