Inward Connections
  Vac Rac TSL-4 Stereo Tube Limiter

Vac Rac TSL-4

Nearly two decades ago, Inward Connections created the TLM-1 (Tube Limiter Module) for their Vac Rac modular processing system. The TLM-1 was highly favored by many of the world’s top recording engineers and when the modular Vac Rac was discontinued, the TLM-1 topology found life as a new standalone, dual-channel unit. Thus, the TSL series was born.

The Inward Connections TSL-4 Vac Rac is the latest incarnation of this classic design. It adds new features without altering the sonic signature engineers have come to revere – Smooth limiting presented with the euphonic character and warmth of tubes. If you want to control the transients of vocals, guitars, bass or the mix bus, without tweaking a whole bunch of controls, the TSL-4 is exactly what you’ve been looking for.

Inward Connections also offers the TSL-4V Vac Rac. The TSL-4V is the TSL-4 equipped with hand-selected and factory-installed NOS tubes. The TSL-4V is a special order item and subject to the availability of tubes required.

Features per channel:
  • 40-Detent Gain Makeup Control – variable control of 14dB of output gain
  • 40-Detent Gain Reduction Control – variable control of up to 40dB of gain reduction
  • Bypass Switch – engages or disengages the gain reduction element
  • Output Switch – Assigns meters to Gain Reduction or Output
  • Hi-Pass Filter Switch – engages 250Hz high pass filter within the gain reduction circuit
  • Link Switch – Links opto cells of both channels for stereo operation
  • Large 3"x3" Illuminated VU meter
  • Zero trim to calibrate the meter in Limit mode
  • Tubes used in both input channels: Input stage - 6072A, Output stage - 12BH7A
  • Power Supply: Pure Class A high voltage tube design with AC Voltage selector
  • Unit dimensions: 3 rack space. 5.25" Height, 19" Width, 11.5" Depth
  • Rugged, well-ventilated, 3U steel chassis design
  • Classic vintage look
  • Transformer Balanced, Line Level, XLR inputs and outputs
  • Gain Reduction: up to 40db
  • Input Impedance: >100k ohms
  • Frequency Response: +/- 0.5 dB @ 20Hz to 20KHz
  • Output Signal to Noise Ratio: -85dB
  • THD + Noise:
    • .015% @ 20Hz (0dB ref.)
    • .085% @ 20KHz (0dB ref.)
    • .15% @ 20Hz to 20KHz (+30dB ref.)
  • Maximum Input Level: +20dB
  • Maximum Output Level:
    • +20dBm @ 600 ohms
    • +34dBv @ 10K ohms
  • Output Impedance: 600 ohms transformer balanced output


Chris Lord-Alge
"....Inward Connections limiters are kind of like old Fairchilds. They have two knobs and one setting: stun. You just insert and go. "
Chris Lord Alge, EQ Magazine, September 2006.

Ross Hogarth
"I had heard a lot of conversation about how great Inward Connections Vac Rac compressor is, so I decided to grab one to try. I plugged it in and set it on a vocal quickly. I was actually comping the vocal so my setting was not really that important at the time. I realized quickly that this compressor is smooth. I mean smooth!

I had looked away, and then looked back and the meter was just slamming over, I mean pegged and I am not hearing it. No sucking, no fur, just smooth and friendly. I actually had to double check to make sure that the insert was in because the sound I was expecting at that degree of compression did not have the evil artifacts I did expect. I had found it finally. The Holy Grail of vocal compressors.

This is your absolute set it and forget it compressor.

Quickly this has become my "milk in my coffee" vocal compressor and I don't drink my coffee with out milk. The Vac Rac is in use every single day in the studio. Thank you Steve Firlotte and Inward Connections for creating such a wonderful compressor. Thank you Mike and Andy Nehra of Vintage King for making it so easy to access. Rock On!!"
Ross Hogarth

Jeff Juliano "I would like to thank you for your work on my Vac-Rac that you repaired at no charge, back in early September. I got the unit back and it is functioning great.

I have to say, this is truly an outstanding piece of equipment. Strap it on your bass and it sits in the track. Put it on a vocal, knock back 10db and you really cannot hear it working. Vocal rides are much easier. Works fantastic on several other things as well...acoustics and BV's to name a few. I think REALLY long and hard before dropping this kind of money on a unit, but this is money well spent. A piece of gear has to do 3 things for me to part with my money: sound noticeably better than a software equivalent, save me time in a mix, and hold it's value. 3 for 3 in my book.

Thanks again, and all the best to you."
John Wilkinson III

Jeff Juliano "The VacRac is hands down the most amazing piece of gear that I have ever purchased. In my experience there is great gear and there is "shocking" gear. This is "SHOCKING" gear. Mike at Vintage King sent me a demo and with one listen I found myself digging for my Amex and a phone.

I always found myself cutting frequencies around 160 and 340hz due to muddiness in the low midrange but the Vacrac just turns all of that into a thick stick of butter which gives the final mix a thick punch that I was always missing.

The attack and release times are PERFECT for lead vocals and bass. It's also amazing on my acoustic guitar buss, piano, hell anything you can run through it. I find myself doing less and less lead vocal rides since I bought this thing. Literally cutting a few hours off any mix that I am working on with better results! When it comes to recalls there are 2 knobs..... It's a no brainer.

Lately I have been reprinting my final mixes through it before sending them off to mastering. It smoothes off all harshness in the high frequencies similar to printing back to an analog 2 track machine. This box is a mixing must have. Steve Firlotte is not only a genius in my book but a hero."
Jeff Juliano

Armando Avila "I got my Vac Rac after reading about it in some Audio forums, then I asked Mike Nehra about it and he sent me the first one. After listening to my vocal tracks, acoustic and electric guitars through it, I immediately ordered a second Vac Rac, because the first one is now busy with my main vocal tracks, so I desperately need another one for my electric guitars, and now that I think about it, I need a 3rd one because nothing sounds like a Vac Rac on acoustic guitars too!!

I have some of the finest compressors and limiters and this is by far one of my favorites, I can't replicate what it does with any other device." - Armando Avila

Latin Grammy nominated producer Armando Avila has worked with RBD, Aleks Syntek, La 5a. Estacion, Belinda, Allison, Moderatto, Gloria Trevi, Natalia Lafourcade, Alejandra Guzman, OV7 and many others.

Michael Angelo "The Vac Rac is a very special peice of gear. After a few days of using the tube limiter I realized it is a MUST HAVE piece in the studio. It really controls transients, while adding a very musical tube character. Recently clients have been tracking more and more in my studio and just tracking with the Vac Rac adds a beautiful character. The unit is very Hi fi sounding. I would say on 50% of the things we tracked we used the Vac Rac in disbelief. We could not imagine tracking without it...ever again....It is perfect for digital recording cause it does 2 great things at 1 time....Controls the transients and adds tube warmth to stale digital sound....

I do not have to do vocal rides like I use to... Its really amazing. The last mix I did with the Vac Rac...the vocal not only sat in the pocket BUT it was also the best vocal sound I have ever gotten. I mean really Mike... It saves me hours of trying to pocket the vocal. The sonic personality of this unit and the way it grabs the transients is 1 of a kind.....THE MAGIC VOCAL limiter...

Here is my chain lately....completely rebuilt pultec EQP1A-3 (with telefunken tubes) into a 1176 (serial # 523) into the Vac rac......Best vocal sound I ever heard!....Stable, bright, smooth....very musical...."
Michael Angelo, The Music Palace, West Hempstead, New York

Johnny Rzeznik "I can't describe the Vac Rac except to say BRILLIANT. It's really an amazing and inspirational piece of equipment: it propels my creativity. I love putting acoustic guitars through it. It is the sound that ignites and multiplies my creative process. Thank you so much!!!"
Johnny Rzeznik, Goo Goo Dolls