[BUILD] CAPI VP28~500 Series~2-Stage Preamp~Official Support Thread

[kante1603]

Hi Jeff,

is there a rough availability time for the  "VP28 Entire Bundle" (I must make my lovechildren become channelstrips )?

Thank you in advance,

Udo.

 

[jsteiger]

Udo, the 2623-1's should arrive tomorrow or Thursday. It will be like a family reunion in your rack!

 

[kante1603]

Udo, the 2623-1's should arrive tomorrow or Thursday. It will be like a family reunion in your rack!

Oh yes,that´s what I wanted to read Jeff ;D.Definetely in for 2 sets!

Udo

Edit:2 full sets ordered and paid-YIPPPPEEEEHHHH!

 

[Winetree]

Speaking of channel strips, Would there be a way to patch the "Love Child"
into the 528 between the preamp and output section?

 

[jsteiger]

Speaking of channel strips, Would there be a way to patch the "Love Child"
into the 528 between the preamp and output section?

It could be done but would require some cleaver routing not allowed for in a normal 500 series rack. You would basically lift the primaries from the first 2623-1 (T2) and "insert" the LC or other EQ there.

 

[funkymonksf]

Jeff,
I really love your aesthetic changes, especially the black pcbs and faceplates! You definitely have offered the whole DIY/recording community with some amazing projects. I hope to jump in on this project soon.

Brice

 

[jsteiger]

....I really love your aesthetic changes, especially the black pcbs and faceplates! You definitely have offered the whole DIY/recording community with some amazing projects. I hope to jump in on this project soon....

Thanks Brice. I just kinda went in the direction I was pulled in I guess. I really do like the brushed and anodized black too. Plus, the silkscreen shop does a super nice job. I have been thru a few hundred plates since I started using them and have not had one single reject due to the printing.

 

[Cgaines]

Hey can anyone help a green DIY guy?
I bought the vp28 and somewhere along the way something went wrong. Whenever I plug up the vp28 to my chameleon labs cps-501 I blow the fuse in it. The build was great. I thought I didn't have any problems. I double checked regularly and had a good experience. But soldering and finding the appropriate components from the BOM is the extent of my knowledge. Any suggestions or tests I can run with a multimeter?

 

[jsteiger]

What is the opamp situation? Do fuses blow without opamps or only with? Which rail(s) goes down?

Maybe a few pics of the PCB top and bottom would help.

 

[Cgaines]

Good call! We're on the right path! I have a gar1731 and a gar2520. I took out both and no fuse was blown. I put back in the 1731 in the same location and no fuse was blown. I removed the 1731 and put the 2520 in its original location and blew a fuse. So I guess the problem is the 2520? I'll post some pics. I hope they'll help. If not I hope we can figure it out.

 

[Cgaines]

Here's the top side

 

[jsteiger]

At least you are narrowing it down.

Next, try the 1731 in the 2520 location. If the fuse blows, it is something on the VP28 PCB.

If not, then I would continue to look at the 2520. The most common errors are the larger BD transistors swapped with each other and/or they could be in backwards.

 

[kante1603]

Success again-2 nice pres done!
Here they are (just a quick shot):



Did only quick tests with a signal generator and an old MD421,but even this was nice to hear on headphones.
Will check them next week in the studio,I bet they´re killer!
I´ll hook up nice chains then too (VP28s/LC53As/LA500s) in my new 51x racks-very exciting

Easy to build (most time consuming was building the DOAs again),no issues except of 2 left-over parts (guess again ;D) and 1 splitlock washer which should have been a lock washer from what I understood.Oh,and the shrink tubes for the I/P signal present leds are too long........ ;D ;D ;D

Again:Thank you very much for this nice and great sounding gear Jeff,another very well done project indeed-CHAPEAU BAS!

Best from munich,germany,

Udo.

Edit:I know other guys did it already but THANK YOU for the isp-led!

 

[Cgaines]

That was it Jeff thanks! I had the transistors switched.

 

[kante1603]

That was it Jeff thanks! I had the transistors switched.

Hi,

Cool you got it sorted.
I wanted to say that some of the parts seem to be a bit far off from the pcb surface.
Beware of shorting things out by touching each other,the area around  R14 to R8 as well as the resistor and the diode arrangement D1A-B seem to be very close to contact in your picture.

Have fun,

Udo

 

[kante1603]

Addendum:

I measured the current,loaded with gar2520s,boosting a -50dB signal to around unity gain.
Results are 59mAs on positive and 55mAs on negative rail.
Given around 60mAs on both one can drive more than 20 pres from a single 51x psu,without even touching the 24v rails,cool!
Sadly I can not measure the inrush current......

Just for info,

Cheers,

Udo.

 

[kante1603]

You like? ;D

 

[jsteiger]

Oh Udo, "like" doesn't cover it.  ;D

 

[kante1603]

So I did some first tests with speech (narrator) and a male singer in our studios.
I used an U87Ai (like most of the times).
The vp28 has always a nice character,but you can get tons of sounds from it!What a great preamp!
It is never "clinical" sounding,always nice to dial in using both the gain and fader pots,a lot of variations can be achieved easily.
The filters work great and give a supercool control over the subs you want to remove or just flatten a bit.
After that I hooked up a channel strip using the modules as shown in the picture in my previous post (vp28-lc53a-la500).
People-this strip is a KILLER!!!
I prefer it over a m*n**y v*xb*x,no joke!

Now up to some more experiments and recording.

Have fun,

Udo.

P.S.:Jeff,I owe you one!

 

[Pliplo]

I just finished my first VP28 and without Chunger's documentation finished! Slowly recovering from my first assembly (and failure) with a 7-0 win streak!

Almost fried my monitors (and ears) when i pushed the MIC button with all knobs at full gain, but hey, you learn from experience xD

If i hear my voice that means i assembled both GAR1731's correctly and nothing's wrong? (it surprises me a little, plus im so bad with a DMM that every pre i finished goes directly in the lunchbox, testing is for noobs......)


=D