Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by Maxx134, Jun 10, 2019.
I think I read that it uses similar hybrid topology that the Cavalli Liquid Crimson used.
Any tube that has linear curves will sound good in these amps. The key is to use linear tubes that are also quiet. EL81's and EL36's (which I use in Citadel) are very quiet IME. I've built this circuit with a few different tubes including DH type 47's as outputs. That's a two chassis amp though as each 47 needs it's own power supply. No need to go that crazy route though.
I'm copy pasting from my site to answer this.
Everybody knows that a tube amp lives or dies by it’s output transformer. A not-so-good output transformer will traditionally always lead to a not-so-good amp. All OT’s are a bit problematic technically, so you should always buy the most expensive one.
These amps utilizes a technical solution which gets around this. OT price is no longer an issue! This is achieved by two design choices: no DC is passed through the OT primary, and the signal to the OT primary is driven by a low impedance source. These choices were not readily available in the past, but now they enable us to get rid of OT related imperfections.
Here you have two imperfect solutions (‘weak’ follower and an OT) that in effect cancel out each other’s weaknesses. The OT primary is such an easy load that the weak follower is overkill for the job (even a tube can manage it!) and produces no distortion, and the imperfect OT is so ‘overdriven’ that it’s parasitics disappear. It doesn’t produce any distortion. The idea of OT’s as distortion producers is a relic from ages past where you only had very compromised ways of driving the primary. Since the output is parafeed there’s no DC flowing in the OT primary.
The OT doesn’t need to be of boutique quality because it is driven to transparency as it is.
This was the last amp I built. It's the stock version of Oblivion without speaker outputs.
Output impedance is about 4 ohms and power output as about 1.5Wpeak into 4 ohms. I haven't measured the power output into higher ohm loads. I've been getting good reports with HD800's also. Power output is not a problem and very little headroom is needed in this circuit for transient peaks.
Yes, it's a toroidal transformer. B+ is 350V and B- is -45V, both regulated with two FET regs.
The meters displays the bias of the output tubes and they look cool. Right?
The chassis I've used previously was made of steel. I just upgraded to a full aluminum chassis. It's HiFi2000 slimline series instead of their Pesante series I used before.
I started by modifying a Little Dot MK6 and then I met MrCurwen online and it just went on from there.
I use Audeze LCD-XC and LCD-3 when testing. I don't tune the amps. They're built to be transparent.
No Lundahl here! That's the whole point of this design. No "boutique" or "audiophile" parts are necessary. Clever design gets around it. All thanks to MrCurwen. I use generic Hammond OT's!
I might be in the future. I've no plans to build a loaner yet though. Keep in mind I have a full time job so this is an evening/weekends hobby for me. So, as long as a have some customers to keep me busy I'm happy. At least for now.
Short and sweet eh?
I'll let you know if I decide to build a loaner though.
I hope this answers your questions. I also encourage you to read the amps page on my site where I explain the ins and outs of the amps.
I LOVE the design and aesthetics! Will keep a close eye on this amp and a short leash on my wallet as my trigger finger is suddenly quite itchy.
Would like to hear how it compares to similarly priced amps such as IHA-1, T3/T4, Mjolnir 2, Sonnet, etc.
Here are mid-build pictures of an Oblivion build from Tomas (@SonicTrance):
"BREAKING NEWS - Internet user MaXXX69 gives big smiley emoji to another shiny pleasure toy"
That is pretty much what I got from the initial review.
That being said, looks like an intriguing design. Casework and meters are beautiful. Cable management is better than some of what I've seen come through the service department with an additional digit on the pricetag.
Wish the introduction were a bit more like your post above, but looking forward to further developments.
Thanks for removing the massive mega-post wide link.
Can you correct the extra linefeeds in the paragraphs of your first post? No reason for this. It's sloppy and lazy - and makes everything difficult to read.
Lol OMG sorry about that dead link to nowhere.
So you wanna suggest to ban me for a link error..?
My intentions was always to help community not to cause issues, and it shown with all my mods suggestions posted whether it was headphones or amps.
My methods are clearly NOT of any type of reviewer, because NO reviewer would dare post comparisons of other amps to guage sound.
You have to at least appreciate I don't pull no BS in my comparisons as I have ZERO interests in coating amps, as I will tell it like it is, because of looking up to you in past actually.
The threads here of amp comparisons and dac comparisons are example.
Frankly, I was expecting harsh criticism and threat of ban from Headfi for telling it like it is, so sorry if review was long winded.
Since when has any review been short.
Most are full of fluff.
Please attempt to use more than one sentence per paragraph. Try to be more succinct. Also, don't be lazy. Making errors is part of being human. Being lazy makes no one trust you.
Ug, Fixing now..
I think I will not be reviewing anymore lol.
Ok I think I fixed those points. Apologies to all. I rushed this as I wans't home when I did this, and I'm pretty sure being lazy has no bearing on trust level.
Aha! So this particular amp is the one that @SonicTrance is building for me. I was planning on sharing my thoughts once I received it and has been in house for a few days.
If the staff here would like to listen to it, I have no qualms packing it up sending it to @purr1n or your choice of SBAF staff member. I trust your critical listening more than mine and it’s always a good to have more point of views from senior members.
Can I humbly suggest upping the ADHD meds ?
If choosing to focus on the review style with response like me needing "attention deficient hyperactive" medication, then I know it caused a " shoot the messenger" response, so time for me to sit back because the topic shouldn't be about me. That would lead to distraction and excuse to avoid this new design "implementation" .
I order to keep the focus on the amp, its design, and the designer (for the benefit of all), and to ultimately discourage troll-type or joke posts like this, I have decided to leave this thread.
It is ultimately distraction from the importance of this discussion.
Try to be fair and open minded and ask away to the designer.
What's new about the design?
Cut him some slack crew - I believe his intentions were good. @Maxx134 - in all the heat there's a bit of light on how to tighten up your presentation to this community; try not to chuck it out with the rest.
Interesting amp - might @purr1n or @Hands have time and the inclination to take @Phantaminum up on his offer? Of course, if it ends up in CO, it might provide a good excuse from us lazy arses to schedule a meet again.
You caught me in a grumpy mood. I apologize.
Thank you for editing your first post. It is much easier to read and I actually read it. I actually want to get this amp in as an SBAF loaner now!
I have a few questions: Do you think you might be suffering from "new toy" or "new (different) sound syndrome"? Were you able to assess stage with speakers (hi-efficiency) in this case? Can you elaborate more on the headstage? Are you referring to image localization precision, stage location and size / boundaries, localization depth and layering?
Secondly, my criticism of your lack is attention is twofold: 1) I genuinely want you to present in a more cogent manner; 2) you seriously, pissed me off (me as a reader).
I went back and edited your second post. I corrected 35 mistakes: missing particles, apostrophes, typos, misspellings, punctuation, extra spaces, etc. I also grouped sentences relating to the same topic into paragraphs, thus eliminating many unnecessary line-feeds. All this, including typing this post, took me 15 minutes. And trust me, I am a far busier dude than you. We are all human and make mistakes, but at least make an attempt.
Finally, if you do not believe that these little things matter to be taken seriously by a reader, then you are dead wrong.
I could be wrong, but at a glance, this doesn't look like a hybrid, as in tube/SS hybrid. I don't see any SS output devices. Looks like single ended triode and pentode parafeed output.
The SS devices are the FETs in the gyrator which serves as the load, where normally there would be a OPT primary, CCS, inductor, etc.
Tubes do voltage amplification and FETs supply current. Oblivion has SE input but balanced LTP output stage. My other amp, Citadel, is balanced from end to end.
Ahh, so the differential output from the EL81s as LTP to cap to OPTs? Interesting. Cool.
Yes, correct. With a CCS tail. Id recommend to read the amps page on my site but it's down ATM. The web hotel has server issues.
The pics above showing @Phantaminum Oblivion in progress has XLR inputs. Those are added option for convenience. The input stage is still SE. Just so there's no confusion. Only one phase / channel enters the amp.
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