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Avalon 747

Avalon Design VT-747SP

4.7 4.7 out of 5, based on 5 Reviews

A great stereo compressor and EQ for 2 bus or mastering stage to fine tune your mixes.


6th January 2012

Avalon Design VT-747SP by Glenn Bucci

  • Sound Quality 5 out of 5
  • Ease of use 4 out of 5
  • Features 5 out of 5
  • Bang for buck 5 out of 5
  • Overall: 4.75
Avalon 747

Avalon VT-747SP Stereo Compressor & EQ

The 2-U space Avalon VT-747SP offers a stereo tube discrete Class A opto-compressor with a six band equalizer. It does not offer separate controls for the left and right channel, which may not offer as much flexibility as some other units. The good news is you don’t have to worry about matching the two channels, and paying for costly Grayhill detented knobs to do so. Though it does not offer the option for processing two discrete signals, you are able to use it when tracking a single source. Avalon Designs advised that the purpose of the unit is for stereo signals when recording such as keyboards, stereo buss compression and mastering applications. As with any unit with tubes and an internal power supply, it is recommended to provide enough ventilation for the unit.

Overview: In looking at the front faceplate from the top left, there is an input knob that has a 0 gain in the middle, with -20 db - +8 db control. Underneath them there is a +10 db gain button, TSP button which activates the tubes into the signal chain, and an EQ pre or post setting to the compressor. Avalon was smart enough to have colored lights which confirm when all the buttons are activated even from a distance. There is an attack and release knob below them. Even though there are 3 levels of controls, the display is not crowded and everything is easy to access. Next is the Side Chain Threshold of up to – or + 15 db for the LP and HP. The LF offers 60, 70, 80, 100, 160, 200, 250, 300, 400, 600, 1K, while the HP offers 600, 700, 800, 1k, 2k, 2k5, 3k, 4k, 6k, 10 k. Having overlapping freq.’s offers additional flexibility. There is a side Chain active button and SC listen button. The ratio goes from 1 -20, and a make up gain which goes up to 10 db.

The 6 band EQ (to the right of the VU Meter) offers a shelf EQ at 15Hz, with a boost-cut of -24 dB to 24 dB. A 125 Hz bell EQ of -8dB to +8dB, a 500Kz bell of -4dB to +4dB, 2kHz bell -4dB - +4dB, 5kHz shelf of -10 db to + 10dB, and a 32kHz shelf of -20dB - +20dB. All EQ sliders have a detent at 0dB. Though the top of the sliders indicate what type of EQ it is (shelf or bell), the sliders do not indicate what freq.’s they represent. I was rather disappointed that Avalon decided not to include this information. However I found my label maker useful in putting in the frequency above each slider on my unit. At the far right on the unit there are two 60 dB range LED meters which provide fast L-R output information, an output control of -20dB - +6dB, as well as a hard-wire bypass EQ switch.

Opto-Compressor: The compressor uses a minimum signal path that uses sealed silver relays for the routing, and bypass functions. The attenuator is a passive controller that has a Class A variable gain make-up amplifier. It offers soft to hard knee limiting, and provides a large VU meter to advise on how much gain reduction is being applied to the signal which sits in the center of the unit. There is also a side-chain path that offers both low and high end filtering. This allows particular frequency’s to pass through the compressor without being compressed. This can be helpful when trying to control a mix that has dominate low frequencies such as a strong kick drum or bass guitar. By selecting the right frequency, you could prevent the compressor from grabbing the low end too much to allow the top end to be compress more smoothly. Many compressors offer a HP filter, but most do not offer both a low and high pass filter. This makes the Avalon 747SP more flexibility. There is a blue light that advises the speed and activation of the compressor. There is even a listen mode for the side-chain for monitoring.

If your looking for a 2 bus compressor to add punch and a forward sound, this is not the compressor. A SSL or Portico comp would be better for that purpose. The best use for the compressor is to use it after you used your 2 bus compressor on your mix. The 747 is a finalizer compressor at the mastering stage that controls the signal, adding a little gel without getting in the way...unless you want it to. There is something very appealing about good optic compressors at the mastering stage. With the hp, lp filter, input, +10 button, output gain control, and the standard controls of a compressor, you have a lot of flexibility on this unit. However you have to understand what each control does and it's best not used in the hands of a novice. For those who understand the controls well, you can get great results that no plug in will match.

Six Band Equalizer: The 747SP offers a discrete Class A six band EQ in a passive design. Unlike a parametric EQ, this graphic EQ does not offer a Q factor so it is more limited for broad strokes. However Avalon Design was smart in offering a low shelf band, three bell mid freq.’s, and two higher shelf bands. For a 2 bus mix, or at the mastering stage, I found the selected frequencies, and their character offer what is needed to control low end, and give a pleasant clean sweetening character to the music. Specifically, the mid freq.’s can help reduce clutter in a mix very effectively. While being a clean EQ it does not sound sterile, and has a touch of smoothness to it. You also have the option to put the EQ before or after the compressor offering additional flexibility.

TSP –Twin Signal Path: With a push of a button, you have a choice of running the signal through a Class A discrete solid state components, or through three high voltage dual triode tubes that are in the discrete amplifiers in the output transformer. Though there is only a subtle difference when engage, there is a noticeable pleasant rounding of the signal when activated.

In use: I ran several different styles of music through the 747SP, as well as tracking instruments with it. The compressor was very effective in helping mixes gel while adding a wider spacial character with the optic compressor. It is able to be very transparent or offer a pleasant clean smoothness to mixes. The EQ is not a surgical type that can fix things, but it can add sparkle, reduce clutter in the mid’s, and control the low end in a mix quite well. I recorded an acoustic guitar in stereo through Rode NT5’s going through my Neve Portico pre’s. The signal was then routed through the Avalon 747SP. In activating the TSP with a ratio of about 3.5, a fairly fast attack and medium release, I reduced the signal up to -3dB. With this setup, the compressor was very clean while controlling the transients. In addition, it added a little bit of fairy dust by gently adding smoothness to the guitar. Regarding EQ, I always believe in using proper mic placement which is the most effective EQ in my book. However when I boosted the 32Khz slider, it added a bit of air to the already enhance sound that the compressor and TSP offered. The result obtained was one of the best sounds I ever tracked with an acoustic guitar.

By using the TSP button, one can add subtle smoothness to the signal. Depending on the source material will dictate if the 2 bus mix sounds better with or without the TPS button. If you (sadly) receive tracks where the engineer squashed the dynamics too much to make the recordings loud, the TSP button can help reduce some harshness one might hear in a mix. It might also sound a little better with the TSP button activated with heavy rock music. When you have mixes that were done well, and you just want to give some transparent control to the mix, I preferred a cleaner signal chain without the TSP activated.

The compressor has the ability to be very transparent in controlling transients just as well as many other optic compressors out there. In addition, by working with the +10 button, make up gain, side chain, and output control, you can obtain a little bit of character to the signal as well. Even so, it is still cleaner than the character of compressors like the Manley Mu or Thermionic Culture Phoenix. It also does not offer the punch of an API 2500 compressor. This is the reason why studios need more than one type of compressor to meet the many needs of their studio. In working with many high end optic compressors, I can say with confidence that the 747SP’s compressor is on par with the best of them. All of them of course have their own personally and strengths which will dictate which one will meet the needs of your studio. However there are two distinct aspects that make the 747SP even more attractive. Besides having a good compressor, it includes a great sounding EQ, and is priced $1,000 - $2,000 less than some of the higher end compressors. With it’s clean control, 3 dimensional sound, and lower cost to many of its rivals, it left me no choice but to add this unit to my rack.

Pros: The compressor can provide a very transparent sound when you want to just control the transients without altering the sound of a mix. In addition, it can add some character and smoothness if so desired. The 6 band EQ is very natural sounding which allows broad strokes to enhance your tracks. The price of the unit is cheaper than many of it’s competition.

Cons: The EQ sliders don’t have labeling for the frequency they represents. Time to get my label maker out. Some may not like the lack of separate controls for the left and right channels.

VT-747SP SPECIFICATIONS
Circuit topology Three (3) dual triode vacuum tubes (Sovtek 6922), high-voltage discrete Class A mode.
Input gain range Balanced, Class A, 20k ohms, -20dB to +16dB with high gain switch
Maximum input level +36dB balanced XLR pin 2 hot
Maximum output level +30dB balanced 600 ohms, DC coupled, discrete Class A

19th February 2012

Avalon Design VT-747SP by edva

  • Sound Quality 5 out of 5
  • Ease of use 4 out of 5
  • Features 5 out of 5
  • Bang for buck 5 out of 5
  • Overall: 4.75
Avalon 747

The Avalon 747 is a "mastering quality", permanently linked stereo tube compressor, with an equally high quality equalizer section. It is so fully-featured that it is difficult to describe in a short review. A visit to the product page is recommended for a more in-depth look at all the many features, but here are some highlites:
Like all Avalon products, the 747 is visually stunning, and has the sound to back up its good looks. Its main intended use is as a final compressor/EQ across the stereo bus, or in a mastering chain. It can be operated in tube or solid state modes. There is a second EQ section dedicated to the internal side-chain circuit, which allows for considerable flexibility in "tuning" the compressor, and is clean enough to use as a program EQ if desired, although the "main" output EQ is quite lovely and musical, so usually it will be preferred. This EQ is switchable in/out and pre/post compression. There are controls for every typical compressor function, however they are not stepped or detented, so precise recall can be an issue.
That minor quibble aside, this is a wonderful piece of kit. I tested the 747 as a master bus compressor on a variety of sources, and it was never unwelcome. It doesn't color the sound, but imparts a gentle, transparent leveling, and definitely unveils any analogue "goodness" that the program may possess, with subtle enhancement to depth, soundstage, and detail; or not-so-subtle if the EQ is employed. The latter is a very nice sounding passive design, with high and low shelves at the _extreme_ ends of the spectrum (15 hz and 32Khz!), and another shelf at 5Khz, along with three wide peaking bands at 125, 500, and 2khz. Not a "surgical" but rather a "sweetening" EQ. The overall sound of the 747 may be best described as "transparent". Beautifully so. In "TSP" (tube) mode there are very subtle harmonics present, but the sound is never cloudy or veiled.
Taken all together, the Avalon 747 is a powerful, flexible, and very desireable piece of high-end, professional equipment, and well worth its price.

24th February 2012

Avalon Design VT-747SP by Tube World

  • Sound Quality 5 out of 5
  • Ease of use 4 out of 5
  • Features 5 out of 5
  • Bang for buck 5 out of 5
  • Overall: 4.75
Avalon 747

I pretty much agree with everything you said in your review Glenn. The only thing is it may take someone who is not used to hp and lp filters to use the product properly to get a great result from it. Some on gearslutz complained that this unit has an attack speed that is too slow, and it has a pillow type of sound. Those people who state this don't understand how to use the controls. With the right ratio, threshold, and hp filter adjustment, you can obtain a gentle compressor touch that will control the tranients without getting in the way. At the same time this Class A unit will impart something quite nice to your signal that a plug in will not give you.

The EQ is more powerful than one would think as well. Boosting the top end will give an airy sound that has the same character of the Avalon 2055 EQ. Reduce the mid's slightly can reduce clutter in a mix, and touch up on the bass can add more fullness.

I know the Avalon 737 sells the most, but people should realize at the 2 bus/mastering stage this compressor and EQ is really very powerful and a lot more affordable than many other higher end mastering compressors. I highly recommmend this unit.

3rd March 2012

Avalon Design VT-747SP by adc004

  • Sound Quality 5 out of 5
  • Ease of use 4 out of 5
  • Features 5 out of 5
  • Bang for buck 5 out of 5
  • Overall: 4.75
Avalon 747

I agree with everything Glenn and Tube World posted, with an addition... this unit also excels as a compressor/eq for individual tracks. I love it on pretty much everything, but it rocks on vocals, bass, and of course stereo tracks like strings, synth-type stuff, etc. The compressor is so versatile. You can set it to be very transparent, or leave a very obvious sonic footprint on the sound. The eq is wonderful, but I do agree that it should have the frequencies on the front panel.

One other cool thing you can do with the 747 is to use it as a mic preamp! There is a +10db button on the front panel. Engage that, plug in a mic and you've got an excellent channel strip with compressor and eq. Works in stereo too! It has enough gain for most mics. No phantom power, of course, but if you have a tube mic or a dynamic, you should be good to go. If you need phantom for a condenser, you can use a power supply or just grab it from your console.

11th September 2012

Avalon Design VT-747SP by SoundKlang

  • Sound Quality 4 out of 5
  • Ease of use 4 out of 5
  • Features 5 out of 5
  • Bang for buck 5 out of 5
  • Overall: 4.5
Avalon 747

Same here. Some more high end and more expensive devices offer an even better sound quality. This is often regarded as the last 10% and the reason why I would say the 747 sound quality is better than a 9 but not a 10. It has a lot of features and thus there is always another try to get an even better result from it. That makes a lot of bang for the buck, but on the other hand is not "easy" to use in the way as for example presets would be.

I like it for all that has been written here. No need to repeat it.

Only points I want to add are:

1) Maybe it is a question of the meaning of the word "transient". I found the 747 compressor to be not fast enough to always and without any exception catch the attack phases of high frequency percussive sounds (e.g. a rimshot). But it is very useful in reducing peak levels of a signal for about 1 to 2 dB.
2) On some material I would like to have an even wider range of control for raising and lowering input gain and output gain than the -20/+18 for input (incl. +10db option) and -10/+6 for output (in the output gain range between -20 and -10 errors in the stereo image can occur, I would use this range only with great caution).

See thread Avalon Vt 747sp shootout for example soundfiles of the Avalon Vt 747sp.

 
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