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-   -   Impressions of Snubbered BrianGT 3886 vs Reg 3886 (http://www.diyaudio.com/forums/chip-amps/54062-impressions-snubbered-briangt-3886-vs-reg-3886-a.html)

moving_electron 23rd March 2005 06:04 AM

Impressions of Snubbered BrianGT 3886 vs Reg 3886
 
I have been listening to a BrianGT LM3886 NIGC built from the standard high capacitance snubbered kit for a week or so. I really like this amp.

In this post I will describe my listening experiences with the BrianGT LM3886 NIGC. Your mileage may vary in your set up of course. In addition I cross to subs at 90Hz, so my comments do not address the case of main speakers that are producing lower frequencies.

The BrianGT LM3886 NIGC has run about 30 hrs. 6hrs was pink noise. The rest has been music of all types. (within reason :) )The amp is connected to a 25v 500VA Torroid. The amp is still mounted on a piece of wood with no sheilding, CAT5 teflon insulated wire, cheap temporary jacks and binding posts.

I posted some comments a month or so ago about my listening experiences comparing the Premium BrianGT LM3875 vs. a Regulated LM3886 IGC. The Reg LM3886 IGC is implemented with carlosfm values using modified Digi01 PCBs. It also is snubbered between the Power supply caps and the regulators which may or may not be a good idea. I described my experience here.

A summary of my experience with the previous two amps was that the regulated definitely had much more detailed sound. Highs in particular were much cleaner (cymbals for example) during both load and quiet passages. Alas I could not shake the impression that the Regulated felt somewhat closed in compared to the BrianGT LM3875 gainclone classic. The soundstage seemed smaller and vocals seemed quite concentrated on live tracks compared to the 3875 NIGC classic. So while I expected to use the regulated IGC most of the time, I indicated that I would definitely still need the 3875 NIGC classic for those times where I wanted the more open sound, particularly on live recordings. But I would be sacrificing some clarity in the highs going to the 3875 “classic” gainclone and experience some slight fuzziness in the highs such as cymbals.

I was suspicious that the tradeoff was going to continue. That is, I expected the unregulated high capacitance BrianGT LM3886 to have similar characteristics to the regulated LM3886.

To my surprise, the unregulated snubbered high capacitance BrianGT NIGC turned out to be even more detailed than the regulated and yet had much more presence in the room. Delicate and subtle sounds are well produced and in general the amp produced a very enjoyable “live” feel.I experienced this on a wide variety of music at both high volume and during quiet passages.

To illustrate will describe two examples recordings.

Buena Vista Social Club:
This is the live recordings of Cuban bands produced by Ry Cooder. They are live in the sense that they appear to be recorded “all at once” while the bands are playing as opposed to separate studio instruments mixed latter. I have always found this to be a finicky CD. When things are just right it is quite engaging. When it is not it can be a bit flat, uninvolving and eventually irritating.

This CD is quite good on the regulated but I am wowed by the BrianGT LM3886. Great detail and separation of instruments and great presence in the room. The amp definitely brought out the live feel.

Some particular examples from the Buena Vista Social Club CD are:

Track 1 – Chan Chan
0:20 Better separation of the two voices in the vocal with the Brian GT 3886.
0:38 Noticeably more delicacy and articulation of the guitar (particularly the light strings) with the BrianGT 3886
2:04 Background bongo much more present and natural in the room with the BrianGT
2:37 Trumpets – More “live” and natural
3:02 Guitar light strings more natural and detailed with the BrianGT

Similar experiences continue throughout Buena Vista Social Club.

This is not to say that the Regulated 3886 is not enjoyable. But the BrianGT LM3886 is just more enjoyable, having a better open and live feel and slightly better detail.

Similar experience with a Grover Washington, Jr. – Live at the Bijou (1977 Vinyl). I always enjoy this album (they be jamming!) but always feel like I am wanting some more detail and presence that I have faith is there in the recording. This amp really pulls the live performance it into the room. Again., Great detail *and* great presence in the room. I was quite wowed.

Identical experience with Bob Marley and the Wailers – Live.

And that is exactly the same story through all the music I have listened to.

So I think the BrianGT snubbered 3886 is going to get a lot of play in my system.

moving_electron 23rd March 2005 06:51 AM

Test setup was...
 
Sources:
1) MMF-5 turntable with Goldring G1012 cartridge into DIY ESP Project 06 phono preamp. The preamp uses carlosfm style bypassed OPA2132s
2) Old Yamaha CD changer as transport into Behringer DEQ2496 as the DAC.

Source select/EQ:
Behringer DEQ2496 used as:
1) Source select
2) DAC for CD
3) Room compensation EQ
4) Linkwitz transform for the Subs
5) Groovy Real time analyzer :-)

Preamp:
DIY ESP project 88 with carlosfm style bypassed OPA2132s and Dact CT2 attenuator

Cables and speaker wire:
1) DIY Teflon insulated coax cables.
2) Parts express Sound king 12 ga speaker wire. (Cheap oxygen free wire)
3) all amps had standard zobel

Speakers:
Mains: DIY Silver Flute W14RC-25-08 / Vifa D25AG-35 2-ways – The John "Zaph" Krutke design.

Sub crossover:
DIY ESP project 81 12db/octave crossover at 90Hz. OPA2134 op amps. (Thinking of redoing this to 150-200Hz)

Subs: 4 sealed 8” subs LTed to 25Hz/.55Q; run stereo, two per channel. Subs amp is a vintage Sansui 8080db. (What a trooper. It never breaks a sweat. Maybe I can keep it running forever! :note: )


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