Litz wire transformers J Steiger!!!

T, you may be the only guy I know that can hear 80kHz. Seriously, I am very curious to see what you think of the Litz trafo's. You really have great ears and seem to hear at a different level than most folks.

well.....  haha, but even in jest, i really appreciate the vote of confidence JS 8)

I seriously need to round out the drum capturing pre's in here, so a pair of VP25's with some big ole 2503 Litz's are around the corner, and another pair of Vp28's are on my short list, i will def opt for the litzwires on those as well, and do comparisons to my other Vp28 pre's once i getem going.

Yes its very interesting.

Part science. Part voodoo.

Funny u say that, the more I creep toward understanding a bit about audio electronics, the more tubes and transformers seem like voodoo with their rather significant impact on sound, spooky!

Link to files:

www.hightail.com/download/bXBiYkJnT011Yk13anNUQw

Thanks Noah! This will be great to get some opinions from folks.

So everyone knows (if you give a rats ass!), here is what I did.

1. Replaced the mic input transformer with a EA2622. The stock one was label as a BT-115K-E. Not sure who makes it. I was told CineMag makes their inputs these days but the can was not marked as such. No manufacturer tag was present. Had to parallel the primaries since the stock trafo was paralleled internally.

2. Removed the 162k R from after the input and replaced it with a 220pF -> 10k series R which is the recommended zobel for a EA2622. There is a 162k load R just before the preamp opamp so the rest of the mic circuit is pretty similar to its vintage counterpart.

3. Physically lowered the .1µF local power rail decoupling caps for both 2520 positions. They use the z leads. The 2520's have gigantic extra long pins so the caps needed to be lowered for the more common shorter pins that Scott and Gary use.

4. Removed/lowered the 68pF feedback cap for the output opamp.

5. Removed the 56pF feedback cap for the preamp stage and replaced with a 82pF. A little less bandwidth and more on track with my vintage board. Some may disagree but we were tying to get closer to the vintage console.

6. Removed all 4 of the 330µF Panasonic bipolar coupling caps from the 2520 outputs. These were bypassed with .1µF film caps which I also removed. Replaced the 330µF's with BC/Vishay 470µF's. The nice expensive ones that most folks use when recapping old Neve's or API's. These are the same AML 138's that I use in most of my kits. The small bypass caps were left out. They were never used in the vintage boards. We are after vintage not hifi.

7. Removed the 100Ω that was in parallel with the 2nd stage output coupling cap. This is used in many API circuits but not in the vintage console channels so ixnay.

8. Replaced both stock 2520's with SL-2520 red dot's from the man, Scott Liebers. sll

9. Replaced both stock output trafo's with the Litz 2623-1's.

And that was it.

I imported the files and level matched them in a PT session of the same rate, both tracks don't even come close to nulling each other out, there are pretty substantial differences to my ears...,

So the modded track has that sweet compression i mentioned earlier, the depth is pretty equal, but by a smidge the modern API has more low end extension and more width than the modded. But so what, the modded has balls and in your face image detail and presence that the other isn't even flirting with, and that's exactly what makes me love the vintage api stuff, it sounds like a record already on Jeff's modded version, while the modern API sounds a bit carved out, unfocused and hollow by comparison to my ears. Anyone hearing the same thing?

I need to listen again and focus in on the top a little more now haha.

Man...I thought the modded channel version had more separation between instruments. More definition. And I thought the modded version had a good bit more depth. Here's the best way I can explain what I hear. In the beginning with the vocals...in the modded file it sounds like the center is hitting me with and then washing out over me. This sounds silly, but a wider center and you can hear the snare hit and then it move out to the sides with the verb...In comparison, the un-modded file sounds a little flat.

Leaving thoughts as I'm toggling between them at the same places in the song.....

The modded is most definitely smoother on the top end, I'd say in the 5k-7k area.

Most definitely has some natural compression happening that is extremely smooth

Sounds like some distortion has been removed on the modded channels as well

I almost want to say that I feel as though the cross talk between the modded channels has improved, I feel like I can sense the vocal's area better on the modded version

The lowend on the modded channels is much more settled, not nearly as pumpy to me.

There is just a slight improvement in the transient response, splitting hairs with that one, but the modded channels handle the transients in a more finished way,

I don't know if I can say that I hear anything extended in the lowend.... it's just handled better. We are talking about a stereo mix going through 2 channels, if this were spread out the benefits that I'm hearing would have a very large improvement over the entire mix. I would imagine there would be much more depth because like I said there seems to be more separation between the channels and a more defined center. If that were spread across the whole console I would imagine Noah mixing would be easier with less eq to carve out some of the build up in the middle. Overall like I said, this is two channels so I'd say all these changes are slight, but if it were over 16 channels I think there would be a very very nice and enhanced depth and staging. I bet your verbs and delays would have a much more defined tail, your drums would be much more open and you'd be grabbing the upper mid/high eq knob much less.

Great job Jeff, I can hear the vintage element you were going for, it's subtle over two channels but if I were Noah I would have this done to all my channels asap.

Just my .02

Upon further listening, the difference in the solidity and density of the images is most striking!
jsteiger can you explain the diffs you heard from stock to mod? I imagine having the before and afts in your own mad scientist dungeon would be extremely revealing? I never really though about getting a newer 1608 and having it modded by you? It's a bit out of my league really, it's kinda like buying a Mustang and giving it to Carroll Shelby for mods haha.

same Q to noah shain

What if he pulled the signal way down on the way in or used the pads and ran the mix through the mic section?