Frequently Asked Questions
andWhat is an input buffer?
An input buffer is necessary to match the impedance of the input to the power amplifier section of the module. The buffer also provides additional gain.
What buffers are available?
All of the amplifiers we sell have a buffer. The PASCAL and Hypex MP Series buffers are on the factory board and cannot be changed. The NCore and Purifi modules use either a factory buffer or VTV Custom Buffer.
How do I choose a buffer?
The default buffer for the NCore and Purifi is the Hypex factory buffer. It offers 14db of gain and uses a very high quality IC opamp and delivers the famous Hypex “house sound.” The VTV Custom Buffer provides flexibility in opamp selection. Most users find the discrete OpAmp selections we offer with the VTV Buffer to be a sonic improvement over the factory buffer particularly in openness and transparency.
With the VTV Buffer how do the various discrete opamps affect the sound?
The discrete opamps offer a range of sonic signatures. My test system is moderately efficient and I base most of my observations on mid range impressions since I think the OpAmp selection is most critical in this range.
I would characterize the range of sound from warmer and laid back to more revealing and forward. Bookending the range is the Sparkos SS3602 with a warmer and more laid back presentation to the Weiss which is most neutral and a bit more forward. In between in approximate order is the Sonic Imagery 994, Sparkos SS2590, Sonic Imagery 995 & 990. I find all of these outperform the factory buffer.
NOTE: Individual impressions of sound quality may vary due to system components including speaker and source components. I am often asked, which is the best? As in so many things in audio, this depends largely on individual taste.
Can I change the opamp in the VTV Buffer?
Yes. I can walk you through the process (involves no soldering) or you can send your amplifier back for installation.
Can I start with the Hypex factory buffer now and upgrade to the VTV Custom Buffer later?
Yes. Most models can be upgraded at a later date. Please contact me to discuss.
I noticed the amplifiers have only XLR inputs, can I use this with an RCA cable?
Yes. Although we install an XLR on the back for input, you can use an adapter such as the Neutrik or Accusound RCA-XLR cables we offer on the website. Using the cables or adapter provides lower noise than using an RCA input with switch. As with any balanced component driven single-ended, the gain will be slightly reduced. VTV uses the Hypex recommended balanced signal input described here with PIN #1 connected to chassis ground. The ideal and lowest noise RCA connection to a balanced amp makes the pin #1 and pin #3 connection at the RCA connector.
I have heard grounding is important using XLR cables. Is the VTV Amplifier grounded properly?
VTV Amplifier uses the AES-48-19 grounding scheme (industry standard) where pin #1 is grounded to chassis (including the XLR jack case). The amplifier has a three wire input which has the ground lead fastened to the chassis as safety ground. All VTV amplifiers are resistant to ground loops and are extremely low noise. You can read more about XLR grounding at www.pin1problem.com.
How long does it take for an amplifier to ship after I place an order?
We keep large inventories of modules and parts and strive to have orders built and shipped with 2-3 days. If there is a delay, we will let you know. We know it can be hard to wait for new audio component.
How do you ship your amplifiers?
We ship our amplifiers by UPS or occasionally USPS Priority mail
I need a multi-channel amplifier. Do you offer multi-channel options?
Yes. Please contact me for options available in amplifiers up to eight channels.
Do you ship outside the US?
Yes. We ship outside the US. We have to date shipped to Australia, Canada, Denmark, Germany, Malaysia, the Netherlands, Norway, Japan, Sweden, Ukraine and other countries. Please contact us for a shipping quote. We can configure your amplifier for the voltage in your country.
What is 30 Day Trial?
Since we sell direct, we realize there is no local showroom for you to try the VTV amplifier and so we offer a 30 day trial program. All that we ask is that equipment be returned in as new condition to ensure a full refund. Buyer is responsible for return shipping.