[diamondears]

The Retro cannot be used as a pre-amp, correct?

 

[rickyleelee]

No pre-amp function but just about everything else. Why by pass those nicey tubes?

 

[diamondears]

No pre-amp function but just about everything else. Why by pass those nicey tubes?

Thanks. That's my next question. I'm hoping it has pre-outs with the tubes just acting as buffers like the iTUBE. I guess I have to wait for the iDSD pro, which has tubes, right?

 

[iFi audio]

The Retro cannot be used as a pre-amp, correct?

 
Hi,
 
As such it is designed to drive speakers and headphones directly, from the internal all tube, Class A amplifier.
 
There actually is literally no point where one could extract a "Preamp" Type signal, the signal flow is:
 
Source (including DAC or Phono Stage) -> Volume Control (optionally enable tone control) -> Tube Amp
 
Additionally, if you use 3D-Sound then the Speaker outputs will receive the Speaker version of the 3D-Sound algorithm while the Headphone outputs receive the headphone version. Due to the way the human hearing works, the processing for speaker and for Headphone are almost polar opposites of each other, though not exact mirror images.
 
All that said, the Speaker outputs of the Retro can be used of course to drive active speakers. It will likely be neccesary to add an attenuator in line, the Retro is designed to output 10V RMS, for a normal preamp output of 2V 14dB Attenuation are required, but it can be done.
 
If driving Headphones, we have some doubts that are many amplifiers currently on the market that would be worthwhile using externally, but it is possibly to take the output from the headphone jack and feed it into another Headphone Amplifier.
 
 
Retro - to Balance or not...
We have had some people query the lack of balanced connections on the Retro. When it comes to line level connections we generally find Balanced connections have few if any advantages in domestic systems (Pro-Audio is an altogether different matter). In many cases balanced connections on HiFi gear in fact are not as good as the equivalent unbalanced inputs. Often to offer balanced inputs and outputs extra circuitry is bodged onto single-ended preamplifiers to allow them to handle balanced connections, but in such cases the unbalanced connections usually offer superior sound as the signal path is usually simpler and of much higher quality.
 
Of course, there are exceptions where the signal path is fully balanced, in this case of USUALLY the single ended signal path suffers and requires extra circuitry to balance up single ended inputs and create unbalanced signals from the balanced outputs. It took a lot of time to derive a solution to this connundrum for the upcoming iCAN Pro that allows essentially absolutely equal levels of performance for all single-ended and all balanced connections.
 
When using headphones the big issue is that at the headphone jack both grounds go through one connection pin. This is potentially problematic, but how much of a problem this is depends on the absolute impedance of this single pin and the relative headphone impedance. Generally speaking, if the wiring of the headphone itself is fully balanced (separate grounds) and a 6.3mm Jack is used (this has a very low resistance - typically < 0.1 Ohm) with high-ish impedance headphones (> 50 Ohm impedance), the problem will normally be minimised to levels where it really does not matter subjectively speaking.
 
Where it matters much more are 3.5mm Jacks where the connection is much higher impedance and often the headphones themselves are very low impedance. The headphone wiring is another culprit as many smaller IEMs etc. do not have a balanced wiring harness to the actual 3.5mm Jack, adding to the problem. Converting the Headphones to a balanced wiring harness can solve many problems here.  
 
In the case of the Retro the entire signal path, except in the final tube output stage is single ended. In this it matches AMR's products, which while fitted with XLR connections remain resolutely single-ended, electronically speaking , because it really does sound better that way.
 
After the output transformer it must be unbalanced again for the circuit to operate correctly. So there is no point anywhere in the signal path where a balanced signal may be successfully tapped off. Adding balanced inputs would require additional Balanced-to-Unbalanced conversion circuitry (the DAC requires some form of analogue stateg so this is combined with the BSL->SE conversion). Adding balanced outputs would require tapping off the speaker level signal and running it through (solid state) circuitry to generate balanced signals. There is no way that the balanced inputs and outputs realised this way would offer superior or even equal sonic performance to the direct, single ended signal path. We like trickle-down as much as the next guy hence here is one instance where iFi benefits from AMR know-how.
 
DP-777 Single-Ended, Dual-Mono

 
AMR deliberately avoids 'balanced' circuitry opting instead for 'single-ended dual-mono' circuitry because we find it sounds better. Yes, there are XLR connectors at the outputs but the internal signal path is SE, Dual-Mono all the way. The outputs are impedance balanced so they do take full advantage of balanced connections where present to reject noise, without compromising fidelity.
 
Have you noticed that most of the famous ultra-fidelity Japanese amplifiers like Kondo/ANJ are single-ended? They all have their roots in first and foremost, sound quality.
 
Kondo - Souga

 
From a viewpoint of buzzword compliance it would course have been be nice to have "Balanced In and Out" on the list of all the other features. We could of course have made the Retro fully-balanced, with double the number of tubes, output transformers and so on, very much similar in the style in which it is done for the Pro series (where balanced connections MUST be fitted for compatibility with Pro-Audio systems). This would have pretty much doubled price and size with ZERO BENEFIT to anyone who does not employ balanced sources and headphones.
 
As we are more concerned to deliver the best possible sound quality per dollar spend to our customers it was an easy choice not offer any balanced connections on the Retro.
 
Meanwhile we would suggest to anyone who believes that unless something is balanced it cannot deliver excellent sound quality to try the Retro, using their own Headphones with a balanced to 6.3mm jack adapter and compare the sonic results from this resolutely single-ended design with their favourite balanced headphone amplifier (at any price). We have good reason to contend that despite (or even because!?) it lacks balanced connections the Retro very much more than holds its own.

 

[john57]

The statement:
 
"It took a lot of time to derive a solution to this conundrum for the upcoming iCAN Pro that allows essentially absolutely equal levels of performance for all single-ended and all balanced connections."
 
That music to my ears that both single and balanced will have the same level of performance.

 

[technobear]

When using headphones the big issue is that at the headphone jack both grounds go through one connection pin. This is potentially problematic, but how much of a problem this is depends on the absolute impedance of this single pin and the relative headphone impedance. Generally speaking, if the wiring of the headphone itself is fully balanced (separate grounds) and a 6.3mm Jack is used (this has a very low resistance - typically < 0.1 Ohm) with high-ish impedance headphones (> 50 Ohm impedance), the problem will normally be minimised to levels where it really does not matter subjectively speaking.

Hmmm. Once again you have me rethinking my options :rolleyes:

The T1 is balanced all the way back to the 6.3mm plug (no nasty adaptors here) and is 600 ohms. From what you are saying it would seem to be a waste of time to cut off the 6.3mm and add XLRs as it is unlikely to make a noticeable difference to the sound - unless perhaps I already owned a headphone amp with balanced output and it happened to sound better used that way. If I were to arm wrestle my bank manager to the ground and buy an iCAN Pro, should I convert the T1 or not. And if I don't, is it too much money to spend on a balanced amp when a single ended one would do.

So... do I need an iCAN Pro? It's a lot of money for a balanced unit where a single ended unit would suffice and may not sound very different to the micro iCAN I have now - even if I convert the T1.

Perhaps Skin already has you working on a revisit of the 'mini' line. All the quality of the iCAN pro but single-ended only and of course cheaper for those of us who already own quality headphones.

I'm thinking I should just stick with the micro line for now and be happy? It already sounds deliriously good with the T1.

 

[Liam2]

The Circuit of the Retro is auto adjusting the bias, no manual adjustment needed. 

Just replace the tubes (not even matched pairs are needed, though it measures better if they are used and we match output tubes quite closely as quads) if they tire out. 

They should last between 5,000 and 10,000 Hours, at six hours per day this is around 3 Years (based on 7,000 Hours lifespan), at 12 Hours halve that and so on.

At the appropriate time I would not consider replacing the output tubes with anything other than the originals and I appreciate what you say about how you quad match them. However, focusing on the ecf82 tubes.....is it necessary, or even desireable that the pentode section or triode section, or both, be matched in these?

You mentioned the 6u8a. Is the 6u8 also a drop in tube and is there a preference between them? Thanks and I'm a big fan of how iFi does business.

 

[iFi audio]

At the appropriate time I would not consider replacing the output tubes with anything other than the originals and I appreciate what you say about how you quad match them. However, focusing on the ecf82 tubes.....is it necessary, or even desireable that the pentode section or triode section, or both, be matched in these?

You mentioned the 6u8a. Is the 6u8 also a drop in tube and is there a preference between them? Thanks and I'm a big fan of how iFi does business.

 
Hi,
 
No matching needed, 6U8a is direct equivalent of ECF82.
 
Background info:
http://tdsl.duncanamps.com/show.php?des=ecf82
 
Cheers.

 

[Liam2]

Hi,

No matching needed, 6U8a is direct equivalent of ECF82.

Background info:
http://tdsl.duncanamps.com/show.php?des=ecf82

Cheers.

Thank you very much for such fast response.

 

[aerosuffly]

Hi guys, I just bought the Retro 50, and I love it, but I do not think the XBass control on my unit works. The switch for XBass is very flimsy - it does not click solidly like other switches on the front panel. And there seem to be no change in the bass with different switch position on both the LS3.5 and headphones.
 
The noise floor on the headphone output is also very noticeable, not dead quiet like on the iDSD Micro.
 
Am I having a defective unit?

 

[john57]

When you move the direct input up or on do you notice any change in noise?

 

[aerosuffly]

  When you move the direct input up or on do you notice any change in noise?

The noise decreases when direct input is on, but it is still not death quiet.

 

[john57]

You may what to open a ticket on IFI audio and explain that the the switch for XBass is very flimsy and too much noise and the noise will decrease using the direct input. Moving the direct input should not be making much if any difference in noise more to the quality of sound.

 

[XjunkieNL]

The difference between the different settings on Xbass should be clearly audible.
As suggested by John open a ticket.
The service, in my experience, is always quick and helpful.

/Paul

 

[Acquire]

  Hi guys, I just bought the Retro 50, and I love it, but I do not think the XBass control on my unit works. The switch for XBass is very flimsy - it does not click solidly like other switches on the front panel. And there seem to be no change in the bass with different switch position on both the LS3.5 and headphones.
 
The noise floor on the headphone output is also very noticeable, not dead quiet like on the iDSD Micro.
 
Am I having a defective unit?

 
Sounds like you have a defective unit.  Open up a ticket with them and see if you can get it replaced.  I had mine replaced after months of issues with it and constant back and forth with ifi.   So far the new one is working well.  Lets hope it stays that way.