[adydula]

Only having 9 head amps, I am getting itchy to build something and am contemplating building Bottleheads top of the line
heaphone amp, their Mainline amp.

I have a slightly modified Crack w/ Speedball but have alwaus drooled over this "high" end amp....

Anyone here have one or have listened via one?

Alex

[timind]

I've built a couple Cracks and am in the middle of a S.E.X. build right now. Haven't heard the Mainline, but maybe it will be next for me.

Have you heard the S.E.X?

[FullRangeMan]

Only having 9 head amps,

Wow, any photo?

[oldnuke]

I've had there Quickie (modded for headphones), version 1 of the S.E.X. amp, a couple of Cracks and the Mainline.  Each was a step up in sound quality, black background and detail.  But the Mainline spanks the S.E.X. amp and sends it home to Momma.  Just my opinion, your mileage may vary, yadda, yadda.  The newer S.E.X. amp may be better, haven't heard it to compare, I stopped looking for headphone amps after building the Mainline.  I run it slightly modified into HD-800's and it sounds great.

[timind]

Well crap, now I'll have to build a Mainline once I get a feel for the S.E.X. (feels dirty typing that)

Question though, what was done to make the Quickie a headphone amp? More than simply adding a jack? I had a Quickie a while ago and really liked it as a pre.

[adydula]

Pictures...

I have most of them on this site "somewhere".....the DIY ones..
I dont have pix of my Schitt Asgard (ss) or Schitt Lyr (tube).

AGDR's Inverting Version of the O2....ODAC on the side.
Marvelous and "rare" amp for sure...only a few of them out there...
The design thought here was to build an O2 like amp that used inverting amplifier stages for the gain and output stages.
The result was a cancellation of the higher-order even harmonics by the inverting stages at a cost of slightly higher background noise.



The Bottlehead Crack with Speedball.
I should say the "legandary" BH Crack....its touted by many as the OTL amp for high impedance amps.
I have to say its a great simple design that just works and works very well.
If I had only high impedance cans this could be the amp to have.
Its tempermental with tubes, or I should say the tubes are tempermental at times...noises, pinging, microphonic etc
but once it settles in its a stellar amp.





Schitt Vahalla 2
A great OTL amp that has morphed somewhat from the original Vahalla 2
Valhalla 2 is a complete re-imaging of Valhalla, with improved performance, higher output capability, lower distortion and output impedance
I can use this OTL amp with both high and lower impedances...drives the T90 and T1's very well and even the DT1350's at 80 ohms...
The DT 1350's on this amp with low impedance setting has bass that thinks its a big as anything else out there!! LOL.
The main reason for buying this amp was to see if the powere available at 600 ohms made any difference over the Bottlehead Crack.
It has the highest RMS power rating than any other head amp that I am aware of.




AGDR Desktop "O2" or what we call the "ODA"
After "rocket Scientist" disappeared many wondered what the desktop version would have been like...
he has a few design thoughts on that on his still up website...

So AGDR took the liberty of putting one swipe at this "ODA" and here is what he came up with.
Its a very demanding DIY build, many parts and costs over $200+.
It can be built wiht a few options and customizations...which cause some folks to not want to do DIY or have to think about what
are the trade-offs and parts etc...
Its the best SS amp I have heard and works with most any headphone except the electrostatics etc.
The front panel is not engraved "yet"...
The two jacks on the front right are for 1/4" and 3.5mm and this amp can run both at the same time, makes comparing really nice.
THe phone jacks are for a unity gain pre-amp output...I use it to drive a AVR at times for my pc.
Volume knob, two power rail leds, 4 position gain switch, clipping led, a front/back input selection swithc and a 3.5 mm DAC input jack.
On the back there is power, DAC input for internal ODAC, and DAC phono inputs (for USB input from PC).
The big thing is this amp has twice the current sourcing capability than the O2.





OPA1622 Integrated Headamp Project:
The next head amp was built from a friend in France who was enamored with the latest new Op Amps made by TI. These were designed for audio use and fit very well with low power head amps. (relative to the norm 2ch power amps!). Its simple to implement and has fantastic specs. The op amp is the OPA1622. It leads the way for a high performance spec wise and LOW cost head amp and its rather small, but with a wall wort. IT eveb has a cross feed circuit, that after testing I wired out and added selectable gain instead. The BIG thing here is that the OPA1688 only comes in "TINY" form factors and is very difficult to install or solder on a pc board! These chips are installed by the big boys with re-flow ovens etc...I had to learn to use a hot air gun to install these chips as well as using flip up binocular magnifiers...they are that small.
Results:
•   DT1350 (80R, 109dB/mW), OPA1622 with +/-5V supply should be ok, it even can reach the max SPL of the can : 129dB
•   T1 (600R, 102dB/mW), max SPL with OPA1622 with +/-5V (clipping at 4.1V) is 113dB. Certainly too short, it should be better with +/- 10 V supply, allowing 120dB SPL max.
•   T90 (250R, 102dB/mW), OPA1622 with +/-5V supply should be ok, max reachable SPL : 117dB








So thats "5" of the amps at present...
Number 6 and 7 are the original O2 amps but with modifications:

One has an AGDR Booster board and the other has different op amps..."1688's"....
The booster board replaces the original NJM4556A chips, you remove them and the board plugs into their sockets, plus some wiring. Different Op Amps are used, OPA827's with a LME49600 current buffer. It lowers the DC offset voltage to the cans down to 50uvolts, has a relay for turn on/off thump. A slew rate improvement and a lower distortion specs.




Ever wanted to build a CMOY using modern parts?
Amps 8 and 9 are Two variants of the cMoy design with the new TI Super audio chips.....OPA1688.
I never built a cMoy and stayed away for objective reasons but with the new TI high perf chips
and AGDR's dogged determination he came up with several iterarions, of which I built all three!
THe neat thing here is the actual TI engineer came online to help and see how "his" new chips perfromed
in the real world.






I actually have more than 9 amps!! I have three AVR's that I use on occasion as well...

So I guess its time to build that Mainline!!

lol
Alex

[adydula]

So why have 9+ head amps? I guess the same reason that people have multiple headphones....in search of something better or different.
I have always been on a budget but like to try new thihngs, circuits and the like...but try to stay on the "cheap" or frugal side of things.

Some of the amps I have built have mega-buck counterparts that dont necessairly sound any better than my basement bargin amps.

They might have prettier cases, bilt aluminum, 1/4 think chassis made from solid copper etc....but sonically I put up some of these low cost diy
amps with the best of them.

I rotate them thru about every other week or so and get to know their sonic signature and do have my favorites and some make certain headphones
come more alive than others.

Lately the O2 with AGDR's Booster Board has once again made me say.."dang this amp is GOOD"...

I know the most important part of the chain is the actual transducer and this is indeed IMO where the biggest sonic change occurs.

I guess its the smell of solder, the heat of vacuum tubes, burnt fingers, and a cold beer make it all worth it!

Ha!
Alex

[FullRangeMan]

Nice set of amps, thanks for posting.

[oldnuke]

Well crap, now I'll have to build a Mainline once I get a feel for the S.E.X. (feels dirty typing that)

Question though, what was done to make the Quickie a headphone amp? More than simply adding a jack? I had a Quickie a while ago and really liked it as a pre.

Just need 2 Speco transformers and a headphone jack.  BHead has a thread on it. 

[timind]

Just need 2 Speco transformers and a headphone jack.  BHead has a thread on it.

Thanks.

[adydula]

I am now looking at two headamps.....yes ..decisioin, decisions....

The desire to build is strong so the mainline seems to be one of the best high end tube amps that is "affordable", relatively..$1199.
You build it, test it, and if things go south you can troubleshoot and repair if ever needed.

The other amp that I am looking at it totally opposite in that its one of the best , if not the best straight wire with gain amp....the Neuchrome HP1.
I dont think anyone here has had one or heard one??

Its indeed a objective built amp that had IMO some of the best 'engineering' behind it. Its built by Tom at Neurochrome in Canada.

"The Neurochrome HP-1 is an ultra-high end headphone amplifier capable of producing up to 3 W into a 20 Ω load at vanishingly low distortion. The HP-1 will drive even the most challenging headphones with the utmost fidelity and natural sonic profile. It is designed to be as close to a straight wire with gain as technically possible. In addition to providing the ultimate technical performance, the HP-1 also provides peace of mind as it contains advanced protection circuitry which will protect your headphones in case of various fault conditions.

Key Features

Fully optimized 4-layer circuit board.
Total harmonic distortion: 0.000017 % (200 mW, 600 Ω).
Total harmonic distortion: 0.000032 % (200 mW, 300 Ω).
Total harmonic distortion: 0.000050 % (200 mW, 32 Ω).
Total integrated output noise: 1.0 µV RMS (A-weighted, 20 Hz – 20 kHz).
Output power: 3.0 W (32 Ω).
Output power: 450 mW (300 Ω).
Gain selectable (+6, +12, +20 dB) by front panel switch to accommodate a wide range of sources, including smartphones, tablets, DACs, and CD players.
1/4″ phone and 4-pin XLR output connectors.
Balanced (XLR) and unbalanced (RCA) inputs.
±0.1 % tolerance Susumu RG-series resistors used in critical parts of the circuit to ensure the best possible performance.
All signal switching is accomplished using relays with gold plated switch contacts.
ALPS RK097 volume control potentiometer.
Well filtered switching power supplies followed by onboard low noise linear post-regulators ensuring the highest power supply performance.
Protection against DC voltage on the amplifier output.
Integrated mains soft start and 320 Joule surge suppressor.
ON indicator emitting a subtle and pleasant blue glow.
International mains voltage compliant (85 – 264 VAC @ 47 – 440 Hz).
All aluminum chassis made in Canada."

The HP! can be had in a DIY format or totally built and tested, from a pcb at$225 to a complete HP1 for $1299 (on sale now).








So there is now a $100 delta.....hmmmm

The HP1 is mostly SMD 0805 devices..small but do-able for a DIY'er.
The Mainline is old school wires, sockets, switches, big chassis and even some wood-working skills!

Ideas, thoughts?
Alex

[adydula]

OK since I am going to spend $1000+ on these amps....I looked at a third possibility...totally not DIY:

WOO Audio WA6SE.

Seems to be a very good amp as well, built like a brick shouse!

hmmm...
Alex
 

[adydula]

Hey Dale...

There is something to be said for DIY for sure....your not that afraid to dig in and start probing...

I have been listening this am to my BH Crack w/ speedball mod and it has a really wide soundstage...and the sound is mellow'er than
my ss amps, like the ODA and O2's...the ODA is just so clean and clear and precise...not as holographic as the crack.

The Woo Audio WA6SE seems to be less "tubey" than most tube amps...so it may be the answer to what I am looking at right now!!

I think the HP1 is the reference straight wire with gain SS amp for sure. Would be nice to have for a reference.

Back to more thought and reading....this is part of the fun..."the hunt"...

 
Alex

[adydula]

Here is somthing that I really like to do when testing headphones, my ODA allows for 2 headphones to be plugged in and it has the power
to do this easily. Here I have the T90's and T1's plugged in and easily swap them. Just have to level match with some tape mark in the swap to get a
good feel on how they contrast...

Alex


 

[DavidS]

I have a Neurochrome HP-1, have had it for about 3 months.  It was built by Tom vs kit.  Really like it, I also have a Mapletree Ear+ - two amps couldn't be more different.  The biggest negative with the Neurochrome is that it is ruthless with bad recordings and poor gear upstream from it (used an old dacmagic with it and combo was unlistenable).  On plus side with mostly good recordings has great detail and drive.  Using it mostly with MRSpeakerAeon Opens.

[adydula]

Thanks David...

I would think the HP1 with those specs would be unmerciful period....I really respect what Tom has done with this amp. I have a strong inclination to build one. But the others are tempting as well....and at this price point I would like to just get it and plug it in and go....still have a few months before the budget will allow so will keep reading and contemplating....

If you get a chance to plug in a set of Beyers let me know!
Alex

[rif]

As time goes on, I find BH's drug references (crack, speedball, mainline) less tolerable, maybe because my son is soon to be a teenager and you see all these opioid stories on the news. It would be hard for me to have serious talks on drugs if I had something called speedball or mainline in the house.

 Of course that in no way diminishes the quality or performance of their products, but I've always been told the adage "vote with your dollars" and i don't think I'd buy from them again.

I'm sorry for being negative/curmudgeonly in a good thread, but I couldn't not say something. I have owned and enjoyed a few of their products in the past (foreplay, quickie, upgrades).  And they have a vibrant and educational forum.

[restrav]

As time goes on, I find BH's drug references (crack, speedball, mainline) less tolerable, maybe because my son is soon to be a teenager and you see all these opioid stories on the news. It would be hard for me to have serious talks on drugs if I had something called speedball or mainline in the house.

 Of course that in no way diminishes the quality or performance of their products, but I've always been told the adage "vote with your dollars" and i don't think I'd buy from them again.

I'm sorry for being negative/curmudgeonly in a good thread, but I couldn't not say something. I have owned and enjoyed a few of their products in the past (foreplay, quickie, upgrades).  And they have a vibrant and educational forum.

mainline is the name of a drug?
and also i think you can caution your teenager about drugs regardless of the name of the amplifier you own.

[Tyson]

As time goes on, I find BH's drug references (crack, speedball, mainline) less tolerable, maybe because my son is soon to be a teenager and you see all these opioid stories on the news. It would be hard for me to have serious talks on drugs if I had something called speedball or mainline in the house.

 Of course that in no way diminishes the quality or performance of their products, but I've always been told the adage "vote with your dollars" and i don't think I'd buy from them again.

I'm sorry for being negative/curmudgeonly in a good thread, but I couldn't not say something. I have owned and enjoyed a few of their products in the past (foreplay, quickie, upgrades).  And they have a vibrant and educational forum.

Just give them different names....

[rif]

Just give them different names....

Of course I can still educate and rename    I guess it was more of an internalization than a projection. Don't think I said that correctly.   Nor was it my intent to turn this discussion away from  the OP's search for amp knowledge, I was just trying to provide my 2cents on one of his prospective amps names, it's not a well known rerefence.

From dictionary.com, mainline:
verb (used without object), mainlined, mainlining. Slang.
1.
to inject a narcotic, especially heroin, directly into a vein.