"Say Hello! to my new little friend"

The 400V rectifier, 41 ct part, has enough headroom for the 160+V AC audio voltage :)

Actually the guanzo v2.2 is a 3rd generation clone of the "so called" 4.5k USD matisse "preamp".
I will shed some light later on the whole story, i am just too lazy now :) lol ...
(I will post a nice and interesting photo-story whats all the fuzz about)
 
OLK,

You seem up to date on these 6N3 preamps. Do you know if my Sain Smart from Amazon is the same as the Guanzo v2.2?
 
PG,
if you refer to the one you posted on previous (30) page. then yes it's a genuine guanzo v2.2.
It has the 4 red cylindric and 2 brownish sugar-cube audio caps.

Unfortunately the v2.2 has a stupid design-flaw:
The audio-ground is conected with heater-plus ...
Read more details about this issue on page 27 #522 & #536

However ... as long as one uses the supplied stock trafo the guanzo works and the big black rectifier get's insanely hot .. but wtf lol it works :)
 
Here's the look that inspires me.

Schiit%20valhalla%20front.jpg
 
Well, the so to speak ... guanzo's father and grandfather and greatgrandfather (here: the original matisse), they all do all have 4 tubes.
Actually 2 tubes (per stage) are just in parallel. Just our poor little guanzo must get along with one.

hm...hmm...hmmm :)
 
Hello all,

After reading one of Poultrygeist's endorsements in another thread, I also got the Sainsmart version of the Guanzo pre-amp. I'd never had or heard tube sound, outside of guitar amps and this seemed like a good, affordable way to get some idea of what the fuzz was all about.
I'm quite happy with it, so I thought I'd post some impressions, and even some measurements and questions related to those.
Having never heard tube stuff before, I wasn't sure quite what to expect. In a way, I wasn't expecting much: I figured, if it just does the job it's supposed to do, it would be transparent, not audible in the signal chain, but the look of glowing tubes would be enough of a justification. I put it in the tape loop of my 90s Marantz integrated, adjusted the volume so it doesn't add gain and switched it in and out of the loop; and lo and behold: it does make a difference to my ears, a positive one. A warmer, slightly fuller bass and a more spacious sound, instruments seem a bit easier to place with the Sainsmart in the loop.
After reading some more here, I changed the four red caps to 1.5 uF 400V WIMAs, as that was what my local electronics shop had in stock. I'm not entirely sure what audible difference this made, I can't really A/B it of course. It still sounds good in any case. I did however take some before and after measurements, which show the same as bazz77's results, and some other things too.
sainsmart mods.jpg
The first image shows frequency response before and after changing the caps, and the response of the soundcard I measured it with. Strangely enough, it extends bass beyond what the soundcard is capable of. For these measurements, the volume knob was set so it provides about 8dB of gain as measured by the level meter of REQ Wizards, which is about 4 o'clock here. Then I took some more measurements at different gain settings, which I've included below.
sainsmart gains.jpg
As you can see, the setting of the volume knob changes bass response and extension, as well as adding some variation (and distortion?) to the treble. Please note the y-axis is only from +3 to -3, so the deviations are rather small really, and I certainly don't hear a problem (mind you, I use the volume knob of my Marantz to set the level, so the Sainsmart operates at a fixed gain over here). I was wondering however, what causes these differences. Is this what bazz77 meant when he said the volume pot is in the wrong place? Does the output impedance change with setting? Or is my soundcard acting strange? A combination perhaps?

Sorry for the long post, just thought I'd share my experience and I hope some people here might be interested in the measurements (or tell me what I've done wrong...).
 
IMO the Sain Smart adds enough color to make my TPA's musical.

I'll take musical and warm over accurate and sterile any day of the week.
 
OK, finally had time to print my case designs from earlier in this thread, came out OK but might do more colourful versions in the future :)... Also thinking of installing white LEDs and frosted plexi in the lo-fi logo as power indicators.. You can find them here http://www.thingiverse.com/thing:1184279 if you would like to 3D print your own..

2965c38caa14689f8bbae00a1970f763_preview_featured.jpg
 
@chauza: Thats the perfect deal.

Or ... the diy way LOL

View attachment 660224 View attachment 660225

The left photo shows my tube socket converter with Dupont-Cables (male - female).
The right photo i have put two ECC81 in parallel into the v2 stage. (Remember the original Matisse has all tubes run as parallels)
What is the advantage in putting two eec81 in v2 stage ?. And second ( i still haven`t tried 12ax7) : If used 12ax7 with converter - the tube is feeded with 6.3v - is this going to work or is some voltage tweeking necessary ?
 
I tried to order version 2.0 from fleeBay, and got sent the 2.2 board. However as I know just very basic electronics, could someone verify whether the board still has this design fault which needs to be scratched out? I've attached the pictures.

I've also assembled and hooked it up to just a standard integrated amp and the bass is good, as well as a nice tube top. Not sure about the midrange as I think 1.jpg 2.jpg the limiting factor there is my integrated amp.

Thanks
 
Still building my Sainsmart box...I've only had the kit for 3 months lol. Building the box is kicking my butt, it's been one thing after another. I've never really built...well...much of anything with wood, so it's a learning experience. Plus I have 2 kids and several other projects, so nothing getting done fast.

Challenges:
- finding a suitable box - found one at Michael's
- picked wrong color of stain - re-stained
- ordering other miscellaneous parts - standoffs, grommets, RCA cables, RCA adapters, upgraded tubes
- cutting holes in wooden box - Dremel broke - borrowed another Dremel
- almost done cutting holes - Dremel bit breaks - go to town to buy new bit - buy wrong size - go back to town to buy another bit
- cutting RCA holes - grommet didn't fit well - tried "tapping it in" with rubber mallet...gently, gently...box cracks (still usable) - drill 2nd RCA hole...too close, wood dividing holes breaks...d'oh!
- order new RCA adapter plate that will also help hold the box together....woohoo (Switchcraft EHRCA2X RCA EH Panel Mount Connector with 4-40 screws, for those curious)! Should be arriving soon. Then hopefully we'll get this thing wrapped up.

Can't wait to hear this thing. Between the kit, tubes, stain, box, miscellaneous parts, I've probably got about $175 in it (I will have lots of leftover parts...grommets, standoffs, etc).
 
The cheap boxes from Michael's won't take the darker stains evenly. The best option I've found is ipswich pine by Minwax

P1160002.jpg
 
The cheap boxes from Michael's won't take the darker stains evenly. The best option I've found is ipswich pine by Minwax

P1160002.jpg


Thanks, looks like I might be using that same box. Are those grommets around the tubes and volume knob? I have some grommets but apparently not the right size. That's what started causing all of my problems...getting the grommets to fit to make it look nicer...my box started breaking on me...
 
Those are large rubber washers with rounded edges. Probably left over from a facet repair kit. It's a little tricky to drill those holes in the lid so the washers actually help fill in the gaps so the tubes look centered in the hole. You can use the red top cover of the Sain Smart as a template for the tube holes.
 
My wooden box from Michael's is around 7" X 7" X 3" and everything fits snugly. I don't think you can go smaller than that.

You'll need some extra risers aka standoffs for mounting to the bottom of the case. I used rubber feet so that I could use nuts on the bottom to hold the stand offs in

place. I looked high and low for a plastic case so the box from Michael's is bit of a trade off as it's made of soft wood but it works.

I might prefer something like this but it costs more.

https://www.amazon.com/gp/product/B...fl_title_40?ie=UTF8&psc=1&smid=A1VRRJFO1VFP1B
 
For people building the Sainsmart preamps, what are you doing for grounding, if anything?

Do I need to ground any exposed metal parts (volume knob...knob is plastic, shaft is metal...and RCA connectors)?

So I could wrap wire or use a forked or ring connector on the shaft of the volume knob and run to a terminal strip, which connects to the safety ground on the IEC connector (inlet connector with switch, fuse, etc)?

Am I over-thinking this?

Thanks in advance, I'm new to this stuff DIY stuff.

@Poultrygeist - I'm looking at you, lol.
 
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