Category: Hardware Review

Heritage Audio Successor Hardware & Plugin Review

Hello, there! I’m Jooyoung Kim, a mixing engineer and music producer.

About half a year ago, I bought a Heritage Audio Successor that had some intermittent noise issues. I kept telling myself I’d write a review after getting it fixed… and, well, here I am finally getting around to it now, haha.

I didn’t originally have any burning desire to get this unit, like, “I have to own this thing!” It was just a good deal, even factoring in the repair costs, so my hand moved faster than my brain, lol.

I was initially eyeing the Behringer 369, but since this is also a diode bridge compressor, I figured why not. Plus, it’s a mastering compressor pushed by Heritage Audio, so I thought the channel balance would be decent enough, and it wouldn’t be a total gamble. So, I went for it.

As expected, there was noise coming from the left channel, so I just dove in and opened it up without much thought. Usually, noise or low output points to a capacitor issue—something simple, right? Or so I thought…!

No matter how much I looked, it didn’t seem like a soldering issue or a blown capacitor. So, I detached the circuit board and swapped the left and right transformers, but the left channel was still the problem.

Testing every tiny component by buying replacements was, frankly, not humanly reasonable. So, I handed it over to the folks at MS Tech for repairs, explaining the tests I’d done and admitting I couldn’t pinpoint the issue.

A few months later, I went to pick it up. When I asked the technician, he said he wasn’t entirely sure, but it seemed like the variable resistor in the left channel was the culprit. On the outside, the components looked fine, but something inside was faulty, haha.

Yeah, I probably underestimated the repair when I bought it. But, thankfully, it’s all fixed now, so no harm done.

And here’s something cool:

Even though I bought it secondhand, I reached out to Heritage Audio’s Support Center to ask if they could provide the plugin, and they happily gave it to me! The plugin is actually pretty solid, and I find myself using it quite a bit.

Hardware Measurements

The channel balance is pretty tight, though, being analog, it’s not completely perfect. You might wonder if the repair changed anything, but even before the noise issue, the balance was about the same.

The extreme high frequencies are slightly boosted, and, like many hardware units, it looks like there’s a high cut around 20kHz. The low frequencies are boosted as well.

The THD looks clean, but it definitely has some character.

The compression curve shows a gentle knee.

Even when limiting, it’s not a completely hard knee.

This unit has a max input of +22 dBu. Since pro audio typically works at +24 dBu, it’s a bit shy of that, but my interface operates at +20 dBu, so it’s plenty for my mixes or mix bus.

The max output is +26 dBu at 600 ohms, so as long as you manage the input carefully, it should work well for mastering too.

Plugin Measurements

The plugin has a unique feature called “Nuke.” It pushes the input by 20 dB for some intense saturation.

The top figure shows the default Frequency Response, and the bottom figure shows it with the Nuke function enabled.

Similarly, the top figure is the default Harmonic Distortion, and the bottom figure is with Nuke activated.

The compression curve feels less like a natural, smooth knee and more like it has a slight two-step bend somewhere.

Personal Impressions

Describing sound in words is probably the hardest thing. Everyone hears and expresses things differently, so… ugh, it’s tough.

Still, here’s what I think:

Hardware
  1. Compared to the Stam 4000 mk2, the high frequencies feel more alive, which gives it a certain quality that feels worth its price.
  2. The center feels a bit prominent (maybe because of the transformers?).
  3. The knobs feel great to turn—probably because they used high-quality variable resistors—and the Threshold and Gain have a subtle stepped feel.
  4. For its full price, it feels just about right.
Plugin
  1. The Frequency Response shows better high-end response than the hardware, but that sparkly, satisfying vibe just isn’t there in the plugin.
  2. The center feels quite prominent. In other words, you might need to tweak it with a stereo imager or something.
  3. It’s got a lot of character. So, when using it on a bus, you really need to pay attention to how it affects the balance.

Looking back, it sounds like I was pretty harsh on the plugin, but it’s actually good! Diode bridge compressor plugins aren’t exactly common (think UAD Neve 33609C or Arturia Diode 609), so it’s a solid new option to consider.

The hardware? Yeah, it’s great! I wish the highs sparkled just a bit more, but it’s plenty good as is.

Next up, I’m eyeing the Warm Audio WA76-D2 for a FET compressor. The audio samples sound amazing, but, as always, the biggest hurdle is money… sigh. If a broken one pops up on the secondhand market, I’m jumping on it.

I sometimes wonder if my reviews lean too technical or analytical, but hey, there’s gotta be at least one person out there reviewing stuff like this, right? Haha.

That’s it for today! See you in next post 🙂

After Modifying My Stam Audio SA-2A

Hello! I’m Jooyoung Kim, mixing engineer & music producer.

Today, I’ll talk about what I did after the article, Record Before Modifying the Stam Audio SA-2A, and how sound changed.

First, let’s review the problems I encountered.

  1. Output gain is similar to input gain, when the GAIN knob is too low.
  2. Compression is started when PEAK REDUCTION knob is too high.
  3. It sounds so dull, like high frequency response is cut off

Otherwise, The Compress and Limit switch was positioned incorrectly. It was simply solved by wrench.

1) Potentiometer Changed..1

If you take off the cover of SA-2A’s knob, you could see a100k potentiometer at each parts. So, I thought that if I change a100k to a50k for gain knob, amount of change is more lower. Also, change a100k to a250k for peak reduction knob, compression would be change more earlier.

So I changed them first.

The green line is SA-2A hardware, the pink line is Waves’ CLA-2A.

It doesn’t seem bad at all! Otherwise, output gain is similar to input gain, when the GAIN knob is too low yet, I ordered A25K and A10K potentiometer too.

2) Vacuum Tubes Changed

I changed my 12AX7 tubes from jj electronics to mullard.

Frequency response and compression curve was not that different compared to jj electronics’. But it sounds much better than before. Harmonic distortion seems to have changed many aspects of the sound.

3) Changed Potentiometer Once Again..2

Upper image is a25k, The lower image shows the a10k potentiometer. You could see frequency response improved when the lower value of potentiometer is used! The problem isn’t solved but it sounds really good.

Red curve is UAD LA-2A Silver face, pink curve is WAVES CLA-2A, green curve is SA-2A.

Compared to UAD, it’s nice that it doesn’t add such an overwhelming saturation. And compared to Waves, I like that it doesn’t have that overly compressed feel.

I think it’s worth trying out more simple tools like this in the future. Next time, maybe an EQ or a Comp DIY kit…!

See you in next post! 🙂

Purchased the Wharfedale D310 4-inch Passive Speakers

Hello, I’m Jooyoung Kim, a mixing engineer and music producer.

A while back, I wrote about connecting passive speakers after I picked some up for free (though I haven’t covered that here on this English blog yet. I’ll make time to write about it soon).

Unfortunately, the ones I found picked up too much external radio interference, so I ended up throwing them away.

But, I still had my old Inkel amp sitting around unused, and I kept thinking it was a shame to waste it. So when I found these Wharfedale D310s for a bargain price, I decided to buy them.

These speakers retail for just $129 overseas, but each one weighs 2 kg, which is pretty hefty for its size.

For audio hobbyists and engineers alike, weight can tell you a lot about a speaker. A heavier build usually means the enclosure is well-designed, and you can expect decent quality woofers and tweeters.

I bought these mainly to refresh my ears when they get fatigued, so sound quality wasn’t my top priority. But the weight alone gave me a good impression.

Interestingly, these speakers have their ports placed underneath. I initially planned to flip them upside down so the tweeters would sit at ear level, but that idea fell apart once I noticed the design.

To my surprise, the sound quality was much better than I expected. At this price point, it made me question why anyone would insist on using active speakers from the pro audio world.

These are also well-shielded, so I didn’t notice any external radio interference. And since these are passive speakers without built-in amps, they have more freedom in the port design, which seems to result in better bass compared to typical 4-inch active speakers.

Even after adding in the cost of my old, cheap Inkel amp, the total was under 200,000 KRW ($150). Compared to similarly sized active speakers, these are a much better deal.

Of course, adding in cables and other extras could push the cost up a little, but you need cables for active speakers too.

I already knew Wharfedale had a reputation for making budget-friendly products, but my personal bias was shattered once again.

The build quality is a bit lacking, but if you look at active speakers in pro audio, it’s often the same. So, I don’t see it as a big issue, especially since this is clearly an entry-level model.

I strongly recommend that musicians challenge their biases and give passive speakers a try. You might be surprised at what you find.

That’s all for today. See you in the next post!

Stam Audio SA-2A Compressor Review

Hello, I’m Jooyoung Kim, a mixing engineer and music producer.

Today, I’m excited to share my review of the SA-2A, something I’ve been eagerly anticipating! Let’s dive right in.

The Struggle with the Gear

If you’ve been following my blog, you might know that this unit had quite a journey before it landed in my studio. Initially, I bought a faulty one with the idea of enhancing my understanding of circuits and practicing some soldering by fixing it myself.

I thought it might just be a simple fuse issue… But after blowing through about five fuses, I took a closer look at the circuit board.

Despite my inspection, I couldn’t find any blown capacitors or burnt resistors. So, I decided to take it to a repair shop after seeking advice.

The culprit turned out to be a burnt toroidal transformer, damaged by overcurrent.

The challenge was that this early version of the SA-2A used a Cinemag transformer, and Stam Audio wasn’t sure if they had any spares left.

After two weeks of waiting for a response with no luck, I asked them to send me the specifications so I could have a custom transformer made.

After installing the custom transformer, the unit finally came to life!

I purchased the broken unit in January, and the repair was completed by early July, marking a nearly six-month battle.

Of course, I was a bit busy, which contributed to the delay, but it was quite the saga nonetheless!

Measurements

As regular readers of my blog know, I like to run measurements on gear, whether it’s hardware or plugins. While measurements don’t tell the whole story, they do help in explaining things more clearly.

I find it especially useful to compare my impressions from using the gear with the measured data, which can sometimes reveal if my ears are having an off day.

The frequency response graph above shows the response with no compression applied. (Keep in mind the peaks and valleys you see are typical of analog gear.) You can see a noticeable roll-off in the high frequencies.

Here’s the frequency response graph with compression applied and gain compensated. There’s a rise in the high frequencies, and the right-hand graph shows noticeable distortion.

As the Peak Reduction increases, harmonic distortion also changes. It seems much more dynamic than using a plugin.

This is the compression curve graph. Strangely, the left side shows the settings for “Comp,” and the right side shows the settings for “Limit.” They seem switched, don’t they? Perhaps it’s just a labeling issue.

Even when using the device, it felt like the settings were somewhat reversed.

Practical Use

I tested the SA-2A on vocals and lead acoustic guitar in a project I’m currently mixing, as well as on some demo vocals for a production I’m working on. Additionally, I conducted a few simple tests.

My observations are as follows:

  1. It’s a saturation machine that adds a hefty amount of color.
  2. It can sound a bit rough, so careful EQing or the use of de-essers/multiband compressors may be necessary to tame it.
  3. As you increase the Peak Reduction, the high frequencies rise, so setting the Input Gain properly beforehand is crucial.
  4. It’s challenging to use on sources that are already colored.
  5. The lack of an Emphasis knob is a drawback.

I wouldn’t say I’m in love with it, but it certainly has its uses.

Since 2017, there’s been an option to use Sowter transformers, and it seems they’ve started custom ordering these transformers from the two companies they work with.

While the raw sound isn’t spectacular, it integrates nicely into a mix. I plan to experiment more with transformer and tube swapping in the coming months.

I hope you enjoyed reading this review. See you in the next post!

I’m always open to reviewing hardware products! If you’d like me to review a product, please feel free to reach out at joe1346@naver.com.