A Bevy Of Bursons – V6 Vivid, V7 Vivid, And V7 Classic Op-Amps Compared In A Non-Burson Amp

Introduction

Three Burson Audio dual-channel discrete operational amplifiers were compared in a Pass DIY ‘WHAMMY’ headphone amplifier to see how my impressions and preferences compared with Jürgen’s trials (here, here, and here) in his Burson Funk. 

In his earlier reviews, Jürgen has given technical and practical background on the earlier V6 and newer V7 Burson opamps, which I won’t repeat here. The main differences between the two generations are that the V7s are physically smaller, so will fit better where there’s less room; are metal-clad, so possibly more efficient at heat dissipation (but get much hotter to the touch!); and, from the specs given here (scroll down and select ‘Opamp Applications’), have a slightly lower max voltage tolerance but draw over twice the current, the latter presumably accounting for the heat. 

For the technically curious, more complete specifications are given for the V7s here and the V6es here. The max slew rate given for the V7 might be a mistake, as it’s much less than the min. 

Op-Amp Rolling and Compatibility Considerations

Op-amp rolling has become very popular lately, the option being used as a selling-point in many new cheap amplifiers and companies like Burson, Sparkos Labs and others promoting their discrete designs as superior alternatives to IC-based solutions from the likes of Texas Intstruments/Burr Brown, Analog Devices et al. However, just because a particular op-amp is compatible with a circuit doesn’t guarantee it’ll be suitable there. While most op-amps ‘designed for audio’ should be fine in most amplifier designs and not lead to catastrophic failure of the op-amp or other amplifier components, in some combinations there could be problems with stability at high frequencies which could lead to unwanted sonic artifacts – subtle or otherwise. 

To attempt to circumvent any such problems when using the V6 & V7 op-amps, Burson recommends installing a low-value ‘bypass’ capacitor between the op-amp’s + and – power-input connections, thereby providing a low-impedance pathway between them. This is suggested by Burson as a ‘no reason why not’ tweak, doing no harm in situations where it’s not necessary. In some amp designs, ‘feedback compensation’ capacitors might be needed if the circuit’s feedback results in too much voltage for the particular op-amp being used.

The WHAMMY board has space for optional feedback capacitors, recommended only if HF instability is obvious. Builders of some WHAMMY configurations have reported measured and/or audibile improvements by adding bypass or feedback capacitance when using Burson or other boutique op-amps. I used neither in my ‘standard’ build and detected no audible HF artifacts. However, this is something to bear in mind when rolling boutique op-amps into different audio amplifiers; an op-amp that works well in one design might not work well in another.

Op-Amp Preferences Vs Headphones (Synergy) in the PassDIY WHAMMY

The WHAMMY is a neutral-ish solid-state amp, although with a bit of emphasis in the highs, with fast attacks and solid macrodynamics. I like it with my low-sensitivity modified planar headphones, which are on the warm side, and also with the neutral- to warm-flavoured Sennheiser HD 6XX. Having tried a few other cheap (< $10) IC chips, my ‘reference’ op-amp in the WHAMMY has been the Texas Instruments/Burr-Brown OPA1612A, one of their ‘Premium Sound’ series which has become a favourite of many manufacturers. Substituting the various Bursons for the TI chip, differences were evident between all; and my preferences were somewhat different depending on which headphones I listened with.

The Burson V6 Vivid increased macrodynamics, and slightly reduced lower-mid warmth and increased upper-mid emphasis. The vocal range came across smoother, but the highs – cymbal hits especially – were not quite as clean.

Switching to the V7 Vivid and comparing to the V6 Vivid, the lower-mid warmth was certainly back, with the bass maybe elevated too. There was a rurther increase in dynamics. Cymbal hits were cleaned up but also further emphasized, along with the rest of the highs. Transients throughout the range seemed faster, with a loss of smoothness, most evidently in the vocal range, being the expense of the increased ‘speed’ and separation (technicalities at the expense of timbre) The highs, while very nicely rendered, were maybe slightly too elevated, which might be a concern for long listening sessions. 

Substituting the V7 Classic for the V7 Vivid, everything became much smoother, generally warm but with loss of detail/clarity at both ends and a loss of instrument separation. Highs were not as clear and vocals also became slightly muffled (or maybe “more romantic”, depending on your preference). The presentation was essentially opposite to that of the Vivid, the focus being on smoothness and integration rather than on technical elements. To me this was not a good complement to my modified Yamaha YH-2 vintage planars. I liked it somewhat better with the less smooth HD 6XX, but compared to the V7V it still felt like a loss of fidelity (and the somewhat underdone highs of the 6XX were not helped either).

Of the 3 Bursons, in this amplifier and with these headphones, the V7 Vivid was my preference. 

Comparing just the V7 Vivid with the OPA1612A, the former seems to play a bit louder, probably because of the more exaggerated macrodynamics. This was not offensive with the smoother presentation of the YH-2s, and with those headphones I might indeed plump for the Burson unless listening to violent material or badly compressed recordings.

The OPA1612A was definitely less dynamic with the Sennheisers, making them come across as more focused in the mids and taking some of the amp’s pressure off the highs vs the V7 Vivid. Although it had less clarity in the  highs and with dynamic elements like cross-stick hits, and seemed more congested with some material, the more natural mix of tonal balance and technicalities – somewhere between the V7 Vivid and V7 Classic – might be less fatiguing and therefore more preferable for longer listening sessions.

Summary and Recommendation

Summing up their relative sonic characteristics in a couple of simple (and not really ‘sonic’) words: The Burson V7 Vivid is more “vivid” than the V6 Vivid, which is more “vivid” than the V7 Classic. Reading between the lines of his comparative review, Jürgen found the V7 Classic more “vivid” than the V6 Classic – the “organic” presentation of which he’d hitherto preferred in his Burson Funk over the V6 Vivid (listening mostly with Sennheiser HD 600s).

The lesson here is that all of personal preferences, headphones, and amplifier model will determine which of these op-amps you might like best. While I hope our descriptions of their sonic contrasts (with our equipment) will give you enough to go on, given the prices of these things I’d recommend that you first try a few different cheap IC-based options to see how (or even, if) they change the character of your particular amplifier; and then see if you can find a source for the Bursons that will allow returns if it turns out you don’t like them or don’t find them sufficiently different to be worth the substantial cost.

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