[labeelen]

Upgrading my Firestone Bobby with 4x Burson V5i has brought:
- overall more musical, refined and pleasing sound
- increased detail
- improved dynamics
- better bas, both in volume and in definition

This really elevates the Bobby to a whole new level.

V5i's needed a burn-in of at least 100-150 hours to show their true potential.

The headphones I used are modified Beyerdynamics T90 (i.e. balanced modification + high-frequency damping modification by CustomCans UK)

 

[Nurgayan]

Hi Louis, very interesting changes!
I expect from you a detailed report on the changes!

In the meantime, I want to place a few links to the reviews on the FSA Tobby.

http://www.hdphonic.com/en/hardware/firestone-audio-tobby/

https://earmass.wordpress.com/2013/08/11/firestone-audio-tobby-the-reference/

http://www.wheninmanila.com/firesto...anced-audiophile-dac-and-headphone-amp-combo/

 

[Nurgayan]

And this is a link to the photos of my FSA Dac and Amp - https://goo.gl/photos/36yTaDE9ro2wvzz69
 

 

[labeelen]

Hi Nurgayan,

In my Bobby moving from opa827 to Burson V5i brought the following changes:

Low-end is better defined with V5i
High frequencies are more sparkling with V5i
Both level of detail and spaciousness is higher with V5i
Opa827 has a little warmer/darker sound signature
V5i has improved dynamics over opa827

In my personal opinion/preference I like opa827 more with HD650 (balanced) and I prefer V5i with my modified T90 (balanced).

Overall you could characterize the opa827/hd650 combination as a warm, smooth and forgiving listening experience. V5i/T90 is more revealing and has a higher sense of being there, but sometimes the level of detail could be a little too much (especially in combination with brighter/revealing headphones).

Based on the above you would expect that the hd650 would be a more obvious choice to combine with the V5i but for me, in the Bobby, there is more synergy between T90 & V5i. It should be noted that my T90 have been modified by customcansuk (xlr + damping kit modification) for balanced operation and to smooth the treble peak.

I would love to test the impact of the V5i on the Tobby but unfortunately that's beyond my budget

(T90 in combination with my custom built beyerdynamic A1 clone (with muses8820) bests all of the above, but that's another story ... haven't tried the A1 with V5i yet)

Cheers, Louis

 

[Nurgayan]

Thanks Louis,
 
very interesting information! It can be seen that the manufacturer has put in the device a big potency on tuning.
I have so far stopped at the configuration of my Bobby on OPA1611.
 
Also I want to try Burson V5i and Sparkos SS3601.

 

[Nurgayan]

Recommendations for using digital inputs for d/a covverter
 
In the process of using Tobby, I noticed that the best option for the signal source is coaxial. Especially when using a quality converter with galvanic isolation.

 

[labeelen]

Nurgayan,

If you like opa1611 in the Bobby you might also try/like opa1641.

Opa1641 has (in my opinion) somewhat nicer highs and a little more detail and ambience information.
Opa1611 has a warmer signature and is more dynamic.

LT1028 is also a great alternative for the Bobby, very musical and with the subtle sparkling highs (a little lacking in the bass however).

L

 

[labeelen]

I can imagine that you prefer coax over fibre...but Tobby excels with USB.

L

 

[Nurgayan]

Nurgayan,

If you like opa1611 in the Bobby you might also try/like opa1641.

Opa1641 has (in my opinion) somewhat nicer highs and a little more detail and ambience information.
Opa1611 has a warmer signature and is more dynamic.

LT1028 is also a great alternative for the Bobby, very musical and with the subtle sparkling highs (a little lacking in the bass however).

L

Thanks Louis, I will take note of your recommendations!

 

[Nurgayan]

I can imagine that you prefer coax over fibre...but Tobby excels with USB.

L

 I fully agree that the USB input in Tobby is implemented with dignity.

 

[labeelen]

Hi Nurgayan,

I have ordered some Muses (02, 8920 and 8820) and Burson V5i opamps to further improve the sound of both the Tobby and Bobby.

After trying several combinations I've settled (for Tobby) on:
OPA827 for I/V
Muses 8920 for LPF
OPA627 for SE

Result is a very tonal rich, detailed and smooth sound.

As soon as I receive the 4x Burson V5i single I will swap all opamps in the Bobby and report my findings.

Hi All,

I have some first experiences with the Burson V5i D(ouble Channel) in the Tobby DAC.
As I only had 2x V5i D available I will limit myself to the impact they had on the LPF section.

In my previous reports I already mentioned the improvements that Muses8920 (and opa1641) brought over the default opa2604. Replacing the Muses with the V5i resulted in the following:
- Bass performance improved, it was more controlled
- High frequency performance is on the same excellent level as the muses
- V5i betters the 8920 on both level of detail and spaciousness
- V5i has a 'cooler' sound signature compared to the 'warmer' 8920
- V5i is a little more expressive and dynamic, 8920 is a little darker sounding

Material I used for evaluation included classics like Peter Gabriel 'Mercy Street' for low-level detail; Paul Kalkbrenner 'Feed Your Head' for bass performance; The Waevers 'Ramblin Boy' for spaciousness and ambience; Tchaikovsky 'Polonaise' for dynamics and harmonics; Johnny Frigo 'I love Paris' for high frequency performance.

As LPF has less of an impact compared to I/V it should be noted that the above mentioned differences are noticeable but subtle.

If I find an opportunity to test the V5i in I/V in the future I will update this review.

(I have added a few pics)

Regards, Louis

 

[Nurgayan]

Hi Louis,
thanks for this detailed review!

Experiments continue, and perfection has no limit.

 

[Nurgayan]

I wonder if anyone tried to change the output resistance to increase the damping factor? I think the results should be interesting.

 

[labeelen]

Hi All,

I have some first experiences with the Burson V5i D(ouble Channel) in the Tobby DAC.
As I only had 2x V5i D available I will limit myself to the impact they had on the LPF section.

In my previous reports I already mentioned the improvements that Muses8920 (and opa1641) brought over the default opa2604. Replacing the Muses with the V5i resulted in the following:
- Bass performance improved, it was more controlled
- High frequency performance is on the same excellent level as the muses
- V5i betters the 8920 on both level of detail and spaciousness
- V5i has a 'cooler' sound signature compared to the 'warmer' 8920
- V5i is a little more expressive and dynamic, 8920 is a little darker sounding

Material I used for evaluation included classics like Peter Gabriel 'Mercy Street' for low-level detail; Paul Kalkbrenner 'Feed Your Head' for bass performance; The Waevers 'Ramblin Boy' for spaciousness and ambience; Tchaikovsky 'Polonaise' for dynamics and harmonics; Johnny Frigo 'I love Paris' for high frequency performance.

As LPF has less of an impact compared to I/V it should be noted that the above mentioned differences are noticeable but subtle.

If I find an opportunity to test the V5i in I/V in the future I will update this review.

(I have added a few pics)

Regards, Louis

Hi All,

I did some further experimenting with Tobby and have some findings I would like to share with you.

Upgrading both the I/V and LPF sections with V5i brought lots of detail but is potentially too much with brighter sounding headphones like the T90.

After some further testing en listening the following setup resulted in the best balance between detail and a warm non-fatiguing sound:

Muses 8920 in |/V
OPA2107 in LPF
OPA627 in SE

Combined with a full-boat V5i Firestone Bobby, Hifiman HE-400i with custom balanced cables by customcans this makes a very nice listening experience that I plan to settle on for some time.

/L

 

[John90]

Does anyone know if this DAC could power and fit a pair of SPARKOS LABS SS3602 Dual Discrete OPA DIP8? Of course, for the XLR output.