Good and bad w/ replacing stock preamp jumpers?

In the past several days I replaced the stock preamp jumpers on my integrated ($2800 retail) with aftermarket jumpers. I was told once by an audiophile he felt that removing the stock jumpers on my integrated (the amp in question was an expensive one-$5k) for aftermarket jumpers can change the tonal balance of an integrated, thus changing the designers intended sonic presentation. What are your thoughts on this? What's your experience with aftermarket jumpers? Also, aren't the preamp jumpers perfoming the same function as interconnects do between a separate preamplifier and separate power amp? And if they are, why do most of these manufacturers use cheap pieces of metal to connect an integrated's preamp to amp? This occurs even in some of the better more expensive integrateds? Why not provide a quality connection that could conceivably improve the sonics of the unit? I've read where audiophiles with integrateds routinely replace these cheap metal jumpers with a quality interconnect and gain improvements. It makes no sense that a manufacturer spends the money on R&D to build a quality integrated with quality parts and then compromises it with a poor quality connection between the preamp and amp when there is all this hubbub in audiophilia about better and more exotic interconnects that will take your system to the next level. If the quality of interconnects are considered by almost everyone in the audio world to be so vital to an audio systems performace why is the quality of the preamp jumper no less important? Or am I way off base here? Thanks for your perspective.
So, Foster9, did the aftermarket jumpers improve your setup? I don't see anything in your post stating one way or the other.

I can vouch that even on my NAD 7140 receiver ($400 retail) replacing the cheap u-shaped wire jumpers with good short interconnects completely changed the tonal balance of the rig, and all for the good.

Perhaps it's just a ploy to sell more interconnects...
What? And kill the audio aftermarket? Same applies for automobiles. Yes, I agree with you but why should audio companies pony up for more expensive cabling when chances are you will? If you're willing to lay down $2,800 for the integrated you will more than likely spend $65 for quality jumpers.
really good question.. I suppose you could always use a 1/2 Meter high quality interconnect of your sonic signature choice... On the old Marantz 70's receivers they had those metal jumpers, if lost, which occured with mine, I had just used a fairly inexpensive audioquest interconnect.
My guess is because the electrical or conductive properties of cables are measured by the running foot, once the connection length becomes about an inch the properties become a non-issue. But I do understand the temptation to mess about with something so user accessible when, if it weren't more difficult, changing the connectors, wiring and circuit board components might also pose similar improvement opportunities.
I replaced the stock wires between pre & power sections in my Nu-Vista integrated..
About 5 inches of custom made KCAG with Eichmann Silver bullets gave a huge leap in transparency & detail and took the amp to an altogether higher level.
For me, it seems as though there has been a sonic improvement since I replaced the stock jumpers; not as much as I hoped however.
I replaced the stock jumpers on my old Bryston B-60 with Tara Lab's The Missing Link. There was a definite change, the sound became more laid back, with a deeper and wider soundstage. With the stock jumpers the sound seemed a bit bright and two dimensional.
My experience has been that when someone states

it seems as though there has been a sonic improvement

there hasn't been any change, just what they had hoped to hear.

You describe them as being "cheap metal." Doesn't that pretty much describe every cable/connector known to man? Even the interconnects that cost a lot of money are actually made from "cheap metal."

There are traces on circuit boards inside the piece that are much, much longer than your jumpers and made from just as cheap metal.

In fact, you might have longer pieces of wire inside the integrated from the connector to the circuit boards. There are others here who claim great impovements from changing these 1 to 2 inch pieces of wire with very expensive sections of interconnects. You asked for perspectives, mine is that this is audiophile nervosa in the extreme.
The point is just to have as good metal inside the jumpers than anywhere else.
You can say, Herman, that it's cheap metal.
It's irrelevant : it's not expensive like platine, of course, but between silver in jumpers, for instance, and poor (really impure) copper jumpers I got with my speakers, though they were very expensive ones, there is a big difference of quality.
A difference that put good jumpers at the level of the whole wiring.

I haven't bought the most expensive jumpers (same brand as my cables), but good quality silver jumpers, not too expensive, and there has been a big improvement in sonic quality between thoses 2 pairs of jumpers.
"My experience has been that when someone states

it seems as though there has been a sonic improvement

there hasn't been any change, just what they had hoped to hear."

Isn't that what happens when someone adds any new piece of equipment, whether it is a $10,000 amplifier or a $60 silver preamp jumper? You hope to hear something different and hope that difference is an improvement.

My experience has been that changing the preamp jumpers on my modest AMC SS integrated makes a very significant change to the overall sound of the system. At least on the same level as changing power cords, ICs, fuses or digital sources.

I have three types of jumpers that I can swap out: the stock metal bars, Audioquest premade PSC+ copper jumpers, and custom made silver jumpers. The sounds of these three are very different, and the two aftermarket jumpers sound considerably better than the stock bars.

I would describe the sound of the three jumpers this way:

-stock bars: brittle, compressed and "shouty"

-Audioquest PSC+: smooth, warm and a bit midrange heavy

-custom silver: Detailed, airy and a little forward

I have been listening with the silver jumpers in for a long time and have made several other modifications to my overall system in that period. I just yesterday put the Audioquest jumpers back in for fun and my immediate impression is that both the bass and treble lost some definition and the sound stage collapsed a bit as well. The flip side is that violins are not as edgy or etched sounding and the overall sound is more relaxed.

Since the Audioquest jumpers have been sitting in storage for a while, they probably need to warm up a bit, but the difference in sound between the silver and copper jumpers in this application is even more pronounced than I remember it, perhaps because other improvements in the overall system have allowed me to hear these differences better than before. In any case, my experience is that preamp jumpers can provide a noticeable improvement in experienced performance. And as with other cables, materials make a huge difference, even if it is only a 2-3" piece of silver in a sea of copper wiring!
I own a Parasound Halo based 2-channel system, a P 3 preamplifier, A 21 amplifier and D 3 universal disc player driving Paradigm Reference Studio 100 v.4 speakers. I recently upgraded interconnect cables from 1.0m Silver Serpent II RCA and XLR to 0.5m PS Audio xStream Transcendent XLRs. The Transcendent cables use solid silver wire. I also upgraded my speaker cables from Premium III bi-wires to PS Audio xStream Resolution Reference 10 gauge PCOCC bi-wires and replaced the stock power cords on all three Parasound pieces with PS Audio xStream Plus SC 10 gauge PCOCC cables. When I did so I noticed my P 3 preamplifier had jumpers between the preamp in and amp outs that looked to be simple chrome plated U-shaped pieces of some indeterminate metal. From their stiffness and the sound they make when you drop them I suspect they are some sort of pot metal. I looked at commercially available jumper cables and did not like any I found. The Parasound jumpers do not have RCA jacks but merely connect the center pins of the preamp in and amp out.

I looked up the spec for the RCA center pin and found it to be 3.2±0.1mm or basically 1/8". I found a source for .9995 1/8" silver rod and purchased a foot at $5 an inch. I then cut 2 pieces 2.5" in length (the length of the U-shaped pot metal piece when rolled on a ruler), bent them to shape using pliers and polished them. I put them in my system last week and could not believe what I heard. I had to swap them out several times to see if what I was hearing was real or imagined. It was real. I played a song I am very familiar with, the opening track from Sarah McLachlan's Afterglow Live. What I heard was a deeper soundstage placing Sarah closer to me and her backing band further back with airier high frequencies and deeper, tighter bass. I consider the difference as significant as that I heard after changing the other cables. During the last week I have been enjoying my system immensely and notice subtle differences for the better with each recording (CD, SACD, DVD-A or LP) that I play.

The upgrade definitely improved my system especially considering the $25 price tag.

IMHO... Its all about conductivity. Most of the stock jumpers you see are plated with nickel which does not give you the conductivity you get from pure copper, gold plated copper, silver plated copper or pure silver. Nickel may have a sound characteristic that people desire, or are use too, in some amps, (there lies the subjective nature of wire) but in my experience, the better the conductor = a healthier signal to amp = improved sound stage. Even cleaning these in out jacks makes a big difference. Again, this is just my experience with my ears..
I love these responses. I am also a believer in everything matters. I think some percieved differences in sound quality are very slight and may not even be happening and certainly not measurable. However, there is no denying many of us claim to hear changes where others say is impossible. Like art our own perceptions vary greatly. Synergy and the human body are things no one understands completely. I think we should all agree if we think something is happening than it just may be and even if it is not, tweaking is a lot more fun.   
I tried the Audioquest RCA pre-amp jumpers and could not hear any discernible difference between them and the metal pins that came stock on my McIntosh MA6900 integrated amp. For reference, the metal pins are insulated and looks a lot like these here, except they are gold plated and stamped McIntosh. I was hoping for something as it would have been an inexpensive upgrade. Alas, nothing.
I tried the Audioquest jumpers on my Bryston B60R Integrated Amp but liked the stock jumpers better.
McIntosh MA6900 integrated amp. For reference, the metal pins are insulated and looks a lot like these here, except they are gold plated and stamped McIntosh.

Try pure silver like the mhconley post, night and day, gold over copper (Mcintosh) vs pure silver, different you will hear it. Copper with silver clad makes a change in the mids, you might not like, clean copper or pure silver, nice change. I've done it and tinkered with a MA6900, and the surround was an MX120, on a house boat. Nice little nugget for 2 dollars worth of good copper or 15 for silver. 

I also have an MA 6900 integrated. I swapped the stock jumpers for a pair of interconnects which I never cared for and the amp went from sounding a bit harsh to very smooth and spacious. Also just cleaning the jumpers and jacks once in while helps. But I prefer replacing them with short cables. 
Replacing stock jumpers is typically very efficacious. Many mfgr. jumpers are poor. If serious about obtaining the best result within reasonable effort/cost, I suggest trying no less than 3 brands/types. 
I like the term " audiophile nervosa" used above. It seems that the conversation is about conductivity, but isn't this a pre-amp to amp connection, almost no current? Low impedance pre-amp out to high impedance amp in? Many of you all must have better ears than me, but I have an EE degree, and worked in lab that specialized in audiometry.

If you want to worry about something consider the galvanic voltage created by the dis-similar metal you use coming in contact with the jacks. The distortion created at each of those connections probably cancels itself out anyway. Keep the stock jumpers, pay an artist their royalties.
Huge difference and not necessarily expensive tweek...try some Monster Pro Studio IC’s or M1000i’s.  I recently replaced several of my multi thousand dollar IC’s with a pair of Monster Pro Stufio XLR’s I had in my old recording bag!  Wow are they frickin fantastic 👍
Replaced the stock u-jumpers on my NAD 7175PE with some small (2”) pure silver solid wire and it completely changed the resolution of this integrated. The stock jumpers are non-magnetic (they seem to be stainless steel). It completely opened up the unit.. and I’ve had this unit for decades. It always seemed a bit dark and syrupy to me.. now it’s much more open. Def not snake oil. 
Scratch that, ended up just opening up the NAD and joining the pre-to- power amp leads inside (its a grey 3-conductor ribbon) .. bypassing those junky RCA in/out altogether. Thumbs Up emoji....Next...