Broadcast Equipment - Part15 Forum

Here's a look at why we do processing and what each function does.

Mark — Fri, 17 Jul 2026 05:50:57 +0000

Shows for FM but applies to AM also.

1140

affordable DAC Impressive Versatility “audiophile quality” Promising Big performance at small price

RichPowers — Mon, 29 Jun 2026 18:40:32 +0000

To me, a "budget priced" DAC means spending like $50 for one... But that's apparently not the reality unless your buying used. I know past discussions indicate that a DAC isn't really necessary for broadcasting part 15 AM - maybe it's not, I comprehend why some say that nowadays it's basically a redundant unit to use in your broadcast chain, but at the same time I can't help but consider one important.

I just don't really know. Nevertheless, I find this $119 new DAC intriguing:

Topping’s affordable DAC teases impressive versatility and “audiophile quality” sound in a compact, portable package
Promising big performance at a small price
https://www.whathifi.com/hi-fi/dacs/toppings-affordable-dac-teases-impressive-versatility-and-audiophile-quality-sound-in-a-compact-portable-package

1138

The new unit’s digital-to-analogue stage is built around an ES9039Q2M ESS DAC chip.
.... also uses a 16-core XU-316 XMOS chip to handle input-signal processing, aiming to deliver “exceptionally high dynamic range and ultra-low noise” ... The analogue stage features a fully balanced architecture, again designed to lower distortion and improve sonic performance. ... .. supports hi-res PCM files up to 32-bit/384kHz alongside DSD256. In terms of connections, the digital side is covered by a USB-C input as well as an optical input and output, while line outputs include stereo RCA and balanced 4.4mm. For personal listening, 3.5mm and balanced 4.4mm headphone outputs are provided.

1139

..‘Parametric EQ’ system, allowing for control of frequency, gain and bandwidth across ten customisable bands so users can tailor their sound to their needs and preferences.. the aluminium enclosure is robust enough to handle being throw into your bag and taken on your travels.
At the front of the DAC’s body is a multifunction rotary control dial, sitting to the right of a large LED display which shows core vitals such as volume level, file sample rate and input/output selection.
The new Topping DX1 II is available from July in black, white or silver finishes, priced at £119 / $119.

Mystery AM Transmitter

RichPowers — Fri, 26 Jun 2026 04:07:43 +0000

Anyone recognize this one? Maybe someone might want to snag it up and find out. I'm guessing it's a homebuilt unit of some kind. I lightened these images a little (front and back) because it's kind of dark on ebay:

-- Hmmm, the images are only 52kb but they won't post, getting an "unknown error" (where's an administrator when you need one?)

Anyway doesn't look familiar, you can see it in the listing, but it'd be nice to archive those images here.

Medium Wave AM Transmitter
https://www.ebay.com/itm/227373237657?

It's listed $115.00 and $9.99 shipping. Used "Like New", "Unbranded".. "cosmetic wear, but is fully operational and functions as intended. This item may be a floor model or store return that has been used .. " Here is the Description:

Medium Wave AM Transmitter

VFO controlled
Freq Range: 650-1725 KHz
Ant: BNC Out
.5W Carrier/1.5W Peak
Audio In
Audio Level Knob
Freq Knob
Audio Cable 3 ft
BNC to Wire Adapter
40 ft antenna wire

IRFP250 mosfet as RF power amplifier.
2N7000 transistor as RF driver.
BD241C AF power transistor as modulator stage.
BD139 transistor as high gain audio amplifier stage.
MPF102 transistor as oscillator.

Not sure if this will work, here's the images direct from eBay:

First AI-Powered Microphone

RichPowers — Thu, 25 Jun 2026 00:33:04 +0000

Though it's still not clear to me what an "Ai Microphone" is, thought it worth mentioning one is coming out:

Meet the World’s First AI-Powered Hybrid Microphone With This New Creator-Friendly Audio System
https://nofilmschool.com/maono-pd500w-ai-powered-hybrid-microphone

... one way to get people excited is to give it a boost with an “AI-powered” tag and voila—you got yourself a new product. ... Maono’s new PD500W is being billed as the world’s first AI-powered hybrid microphone. ... The pitch for the new Maono PD500W traces the lineage of audio recording back to its earliest days, which unarguably has needs that have changed over the past hundreds of years. . ... offers a mix of wireless recording capabilities, USB-C simplicity (always nice), XLR flexibility for higher-end work, built-in recording protection, and a new generation of AI-powered workflow tools.... highlights include 147dB Max SPL, 48kHz/24-bit sampling rate, and a workable cardioid polar pattern. ...... to launch on Kickstarter soon, with early-bird rewards starting at $359. You can also find more info on the company’s website here https://www.maono.com/products/maono-pd500w-hybrid-microphone-for-podcast

Schlockwood SW210 is shipping to initially interested folks

John — Wed, 24 Jun 2026 13:19:15 +0000

Mine is on the way. Will report on specifics after some time with it.

Schlockwood site error

RichPowers — Tue, 23 Jun 2026 21:36:51 +0000

I check on Schlockwood.com a few times a month to see if the budget Schlockwood unit has hit the market yet, but when I checked today I couldn't access because Google blocked me with a privacy error:

Your connection is not private

Attackers might be trying to steal your information from www.schlockwood.com (for example, passwords, messages, or credit cards). Learn more about this warning net::ERR_CERT_DATE_INVALID

I took the "Advanced" option and tried to enter anyway but was surprised that it still refused to let me access, it just gives me this error:

www.schlockwood.com normally uses encryption to protect your information. When Chrome tried to connect to www.schlockwood.com this time, the website sent back unusual and incorrect credentials. This may happen when an attacker is trying to pretend to be www.schlockwood.com, or a Wi-Fi sign-in screen has interrupted the connection. Your information is still secure because Chrome stopped the connection before any data was exchanged. You cannot visit www.schlockwood.com right now because the website uses HSTS. Network errors and attacks are usually temporary, so this page will probably work later.

What is HSTS? I never heard of it

Radio Systems TR6000 10 Watt AM transmitter on eBay

RichPowers — Wed, 22 Apr 2026 20:24:08 +0000

I think I mentioned this being on eBay in the midst of our Schlockwood/Culbert thread a couple days ago. It had recently been listed and some one bought it yesterday for $500, it wasn't up there long.
Radio Systems TR6000 10 Watt AM Broadcast Backup Transmitter - Tested & Working
https://ebay.us/m/kwNeUy

Tubes in Audio Gear; Feature or Flaw?

RichPowers — Tue, 21 Apr 2026 21:59:26 +0000

I thought this was an interesting article. I've noticed modern gear that utilized tubes, I always suspected they were just some kind of marketing scheme retro thing, - though I really don't know anything about it's actual characteristics. This article explains at what point the tubes function come on to play when it applies to DACs. Key excerpts below:

A Popular DAC Category Is Selling You Measurable Problems as ‘Features’,
https://www.headphonesty.com/2026/04/dac-category-selling-measurable-problems-hifi-veteran/

... Speaking at the Audio Show Deluxe 2026, Franassovici drew a clear line ... “There’s a lot of people making DACs out there,” he said. “I call them boutique digital. They want things to sound like turntables, so they stick tubes inside there.” ....

To evaluate that criticism, it helps to look at where tubes sit in the signal chain and what they change. A DAC’s primary role is conversion. It takes digital data and reconstructs it as an analog electrical signal. This process involves filtering, noise shaping, and reconstruction. All of it happens before the signal reaches any tube stage. Tubes are typically added to the analog output stage, after conversion is complete. At that point, they do not affect how the digital signal is decoded. They shape how the final analog signal sounds. .... tube stages can introduce additional noise and distortion. Some designs may exhibit a slight high-frequency roll-off, depending on implementation.

Bottom line, the qualities that make tube DACs sound warm can also be tied to measurable changes in the signal.
In practice, tube stages introduce even-order harmonic distortion, subtle compression, and gentle frequency shaping. These effects are often perceived as warmth or smoothness. ....

Franassovici’s criticism becomes more pointed when applied to pricing. Tube-equipped DACs command higher prices. These products are usually marketed around qualities such as warmth, musicality, and a more “analog” presentation. ..... Technically, his point holds. Tubes do not enhance digital conversion. They modify its output. Whether that matters depends on what the listener values more, accuracy or a particular sonic character.

The debate ultimately reflects two different definitions of “performance” in audio. One is rooted in fidelity, and the other in personal preference.

Schlockwood 200 vs Cuthbert processors

Mark — Mon, 13 Apr 2026 18:41:51 +0000

Here is what I found using both and comparing the two. The Sclockwood although made as an AM processor it can be used fine for FM also provided you are happy being in mono as FM works better in mono transmission and only a small change with the jumpers on board is needed for FM operation(disabling the pre-emphisis so flat response), not using the positive peaks control. The Cuthbert operates in stereo(two channel), unbalanced in and unbalanced out for stereo operation.
The Schlockwood has a mono balanced TRS output so to use with FM or AM with an unbalanced two channel input to the transmitter a small easy mod has to be done at the output with the wiring in the audio cable or on the circuit board of the Schlockwood to be compatible with the transmitter input i.e. Decade MS 100 or Procaster studio interface.

Using for FM and AM here's the difference in operation. They both achieve the desired result in different ways. The Cuthbert has 3 band compression and release for 3 frequency bands and once set it stays that way but if one song has the tonal balance different from another song(which it does) it doesn't work as good as the Schlockwood at keeping the bass treble and mid equal in each track. With the Schlockwood, the incoming audio is analyzed and reduction is applied where it is needed and not applied where it isn't and each track keeps the same bass treble and midrange the same regardless of the original audio a bit better than the Cuthbert so you sound more close to the commercial stations in that regard. That also keeps the on air volume more equal with each track and with the Cuthbert there still is some songs sounding louder than others and some sounding more bassy or trebly and this is controlled better with the Schlockwood. That doesn't mean the Cuthbert is bad, it does a good job but if you want more perfection and get closer to how a commercial station sounds I have to say the Shlockwood gets it closer. I have in the last two weeks with being on FM done an in depth comparison of the two. Hope I explained it right!

Advantages of the Cuthbert: works on common 12 VDC power supply, 2 channel output for stereo broadcast, works with any transmitter input and does a good job doing what it is supposed to do.

Disadvantages: can't adapt to input tonal imbalance of different tracks to keep each track sounding like the other as broadcast stations do.

Schlockwood advantages: keeps tonal frequencies pretty much the same with each track as compression is applied where needed through an AGC. 3 LEDs show the reduction and it is different for different tracks.

Disadvantages: needs a not as common 18 volt isolated switching power supply, can't work with battery. Needs a small mod to work with an unbalanced input like a Decade MS-100 or Procaster studio interface.

Conclusion, Cuthbert is good and an excellent choice for the more affordable price but the Schlockwood is better if you want to sound closer to the way commercial stations do. The Cuthbert is the choice if you want stereo broadcast capability and have a common 12 volt DC operation.

Audio, USB-C vs.. 3.5mm jack

RichPowers — Mon, 13 Apr 2026 08:08:47 +0000

Here's some audiophile stuff that might not just be pycobabble, this applies to phone and laptop outputs alike

USB-C Vs. 3.5mm – Which Port Delivers Better Audio Quality? https://www.bgr.com/2141172/usb-c-vs-3-5-mm-which-port-has-better-audio-quality/

.... a 3.5mm jack relies entirely on the device's internal audio hardware, including its DAC and amplifier, while USB-C typically sends the audio as a digital signal without converting it, leaving that job to an external DAC, whether that's in a dongle (adapter), or built into the headphones themselves. This means USB-C can enable better audio setups, with cleaner sound, more power, and less distortion, but only if the external hardware is actually good. ...

.. After all, with a 3.5mm jack, the sound quality is fixed by the phone, while with USB-C, the result depends on the quality of the external hardware, whether it's the adapter, the DAC, or the headphones. In other words, the analog audio is predictable, while USB-C gives you more range for a better experience.Smartphone makers in general phased out the 3.5mm headphone jack to save space, improve water resistance, and push wireless audio. ...

... By comparison, a 3.5mm jack is a closed system, and it continues to be limited by the internal hardware of the device, whether it's your laptop, tablet, or speaker.

In the end, USB-C won't magically make your music sound amazing. It also depends on where you're getting it, ... This is why, for most users, the difference between 3.5mm and USB-C doesn't mean much, because most people aren't willing to spend a lot of money. Still, if you want to take your listening experience to the next level, a digital connection with a great external DAC is the answer.