You will find these gadgets all over Hollywood CA in analog audio settings.
I've repaired and calibrated dozens of them.
henry matchbox
https://www.google.com/search?client=opera&q=henry+matchbox&sourceid=opera&ie=UTF-8&oe=UTF-8
They are just opamps converting both ways in a single box.
G²
While I appreciated all the other informative replies I must say that I think there is a fundamental misunderstanding.
As a matter of fact the question of the OP was just the following
so, if I'm not wrong, he asked for a direct experience with RCA/XLR adapters and Topping power amp L90D.
Here because - while it seems that nobody solved that enigma - I allowed myself to point out that at least a couple of authoritative magazines had stated that you can use adapters with Topping L90D power amp, and maybe if they had said it means that they knew what they were saying. 🙄
😉
As a matter of fact the question of the OP was just the following
so, if I'm not wrong, he asked for a direct experience with RCA/XLR adapters and Topping power amp L90D.
Here because - while it seems that nobody solved that enigma - I allowed myself to point out that at least a couple of authoritative magazines had stated that you can use adapters with Topping L90D power amp, and maybe if they had said it means that they knew what they were saying. 🙄
😉
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LA90 D uses a 64V single supply. I think they created pseudo 0 potential by using 2 x 4700uF / 35V DC caps in series, in which case there's the possibility that an internal 0 volts rail might be sitting at 32V DC (to the outer world).... it all depends on how they executed their design....
So, that dire warning is completely warranted... in my opinion.
I'd open the thing and figure out what's going on BEFORE using RCA to XLR adapters...
My suggestion to you is to consider a single-ended to balanced signal transformer.... or, an OPamp balanced driver/buffer.
Finally a real answer! 👍
Always conceptually opposed to any kind of adapter (unless very strictly necessary), especially when that adapter someone is going to put it on the signal path. 🙄
Better a new preamp at that point! IMO
Always conceptually opposed to any kind of adapter (unless very strictly necessary), especially when that adapter someone is going to put it on the signal path. 🙄
Better a new preamp at that point! IMO
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Total speculation. It's extremely unlikely there is 32VDC sitting anywhere near the input jacks. That would be horrible engineering and a complete faceplant from Topping......which is not something they do.
@ulogon After all this discussion, you're still not convinced? My goodness.
Dave.
I'm glad someone posted those links! And I'm glad I read the thread - because I would have posted precisely those links too...
Can I have my own preferences?
Okay!
So, please don’t provoke me, thank you!
You believe to have the truth in your pocket, I've my preferences instead.
So, please, stop here with me.
Thanks!
Davey,
I have to ask the obvious question have you actually heard a Stereo Coffee? Chris Daly is very helpful and helped with finding a very good enclosure and PSU. The very first LP I tried with the S/C was Joni's - Hejira 2014 - if I could go back in time it would be the 70s for so many reasons and it was listening to this LP that convinced me. With the S/C it was more than three dimensional - it was organic.
ulogon - glad you've had a very positive with the Topping pre90 - transparency for me is the goal with all equipment and components that's why Z foils and K73-16s will always replace resistors and caps in the signal path of most of my gear.
My only follow up question has to be - what Tx and how to configure it for RCA in and XLR outs. I can make shielded i/connects but always found they seriously distorted the signal. This was after 3 years making all kinds of configurations. I did for a short while sell the unshielded i/cs but without purpose made jigs I couldn't justify the prices I had to charge. Virtually all connectors disregard basic physics and the prices charged for the best are a sick expensive joke.
Gear - Kenwood KD 990, AT 33EV (33SA) (NOS) Pickering XLZ 7500S, NOS Shure VN53E, NOS Acutex M312 11STR, phono stage Talk Electronics MC3, Stereo Coffee preamp/volume control, Marantz 6007 CDP (brilliant beyond it's price) Heybrook Sextet Mk1V speakers with externalised passive x/over and sealed Toningen tweeter chamber. Retired - WAD KAT88 power amp, pre 2 PSU/phono and preamp. Own design multi conductor silver/s/plated unsheilded i/connects for phono et al.
No, not that particular LDR Stereo Coffee unit, but I have auditioned a few others.
But regardless, subjective evaluations are irrelevant since they have no basis for discussion. My comment referred to the bench performance of the units. That's why I said "objectively speaking."
Cheers,
Dave.
But regardless, subjective evaluations are irrelevant since they have no basis for discussion. My comment referred to the bench performance of the units. That's why I said "objectively speaking."
Cheers,
Dave.
That amp uses a single rail supply, but it does not have a sound coupling/DC blocking output capacitor...? How did they get the 0 V DC offset without that cap? => the amp is already bridged OR they used the series caps (2 X 4700uF) to create 0 volts midpoint, which would have to be used for feedback as well. At the same time, the amp is actually bridgable for double the amount of power... So they probably used two series capacitors....
So based on the above, I have a few questions here that I can't get the answer to easily, without checking that amp myself. Hence, I would not use adapters RCA to XLR straight away. I do not know how is the feedback (from that artificially created 0-point speaker output) fed back to a differential input stage... which end?? Is it -IN, or +IN? How are these two points connected to the XLR input pins?? So, what would happen if I connect the RCAs shield to either +IN or -IN? Kaboom, or bang bang kaboom (all military, technical terms straight from Sargent Bilko). Not to mention a brainstorm fart thinking, on top of everything, what happens when I place that thing into actual bridged mode AND want to use adapters...
Of course, Topping could've chosen to AC couple the inputs...
An easy solution: an input single-end-to-differential transformer or an OPamp differential driver.
So based on the above, I have a few questions here that I can't get the answer to easily, without checking that amp myself. Hence, I would not use adapters RCA to XLR straight away. I do not know how is the feedback (from that artificially created 0-point speaker output) fed back to a differential input stage... which end?? Is it -IN, or +IN? How are these two points connected to the XLR input pins?? So, what would happen if I connect the RCAs shield to either +IN or -IN? Kaboom, or bang bang kaboom (all military, technical terms straight from Sargent Bilko). Not to mention a brainstorm fart thinking, on top of everything, what happens when I place that thing into actual bridged mode AND want to use adapters...
Of course, Topping could've chosen to AC couple the inputs...
An easy solution: an input single-end-to-differential transformer or an OPamp differential driver.
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I see you can’t help but bother me, okay.
Please note that you, just as all other posters, but @Extreme_Boky, have completely misunderstood the question of the OP and and you gave inappropriate and unsolicited answers.
As already said, it is quite obvious that adapters can be used as there are thousands of them out there, so why to reply the following?
We already knew the above, so why did you answer the obvious?
Furthermore calling it a definitive answer, you know the existence of the Internet, don't you?
Well, the Internet is just full of "definitive answers" as yours.
Simply, the OP didn’t ask what you "answered"!
About the SQ of adapters you replied to me the following
So, how can you say that? (bold is mine)
Can you prove what you say?
Have you tried and listened to all the adapters out there?
Obviously not, you say it only because it is your belief, that you can not prove!
Not happy enough with what you just said without being able to prove nothing you would also convince me that I can easily use the adapters on the signal path of my system because the adapters have no influence on the Sound Quality.
This is just your opinion, not the truth, so no comment seems necessary, that’s why I asked you to stop, but you couldn’t resist answering me again: well, please stick it in your head that I don’t believe in your statement at all!
Okay, then there’s the old thread existing on this Forum that I linked where you were saying something.
In that thread the argument was the exact opposite compared to the argument here, for me the difference was not clear why I had never addressed that specific topic before and why I'm not at all interested in that specific topic, just because I do not use adapters of any kinds.
Then @MAAC0 has linked The Rane Library and after that you have linked the specific documents inside the Rane library who showed your reasons, I've appreciated your linked documents (even if I don’t care at all about their subjects) and I gave you a "Like".
So why do you still keep bothering me? 👎
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@Extreme_Boky
You're still speculating. I don't believe the possible DC voltage condition at the input jacks actually exists. But, I admit I could be wrong.
The external supply for this unit is single voltage, but that doesn't necessarily mean the internal amplifier is a single rail design. There are numerous ways to accomplish that and also isolate the PS DC potential from the signal circuitry.
Regardless, when you/me have actually tested one we can report back. 🙂
Dave.
You're still speculating. I don't believe the possible DC voltage condition at the input jacks actually exists. But, I admit I could be wrong.
The external supply for this unit is single voltage, but that doesn't necessarily mean the internal amplifier is a single rail design. There are numerous ways to accomplish that and also isolate the PS DC potential from the signal circuitry.
Regardless, when you/me have actually tested one we can report back. 🙂
Dave.
Please note that I realized just now that you mentioned me just because you did not put the symbol "@" just before the nick, in that case the system informs me that you mentioned, otherwise I've to read it between many posts and I might not notice it.
However, yes, that preamp has extreme transparency that I appreciate so very much in my system.
It costs about 600.00 bucks, but it has been compared to preamps costing about 20,000.00 bucks, so draw your own conclusions. 🙂
JFYI and FWIW I've also a Stereo Coffee preamp. 🥷
I can confirm that the kindness and preparation of its designer (C. D.) is second to none, but I'm afraid that the preamp does not have balanced outputs though. 😉
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Believe me, I couldn’t be calmer. 🙂
Especially because I’m not interested at all in your claims that you can’t prove at all. 😉