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SE84 clone headhone amp (Read 4719 times)
funch
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SE84 clone headhone amp
03/01/21 at 22:50:24
 
My amp is a duplicate of an SE84 but using Transcendar headphone output trannies. I've learned a lot with this build, especially how different rectifier tubes have different voltage output, which may account for the differences in their sound.

I still have to install the anniversary mod's and try to remove a low-level hum, but it sounds fabulous.




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piezoman
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Re: SE84 clone headhone amp
Reply #1 - 03/02/21 at 16:51:56
 
wow, that is fantastic!
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DPC
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Re: SE84 clone headhone amp
Reply #2 - 03/02/21 at 17:29:54
 
+1  :o
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Mac Mini, PS Audio DAC, ZROCK, CSP, SE34, RL3
or
Sony TV, Sonos ARC, Sub V3, 1's
or
Oppo, or CXN, SE84C+, LaScalla or Tube Tots
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Brian
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Re: SE84 clone headhone amp
Reply #3 - 04/01/21 at 03:27:57
 
A wonderful thing to build!
Have you any thoughts on the cause of the hum?

Brian
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funch
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Posts: 127
Re: SE84 clone headhone amp
Reply #4 - 04/02/21 at 23:23:12
 
Thanks. Yes I did solve it just a couple of days ago. The problem was the power supply. I installed a 15H/75 mA choke between the filter capacitors.  I also installed a 250 ohm/5W resistor in series with the choke to get the B+ power to the correct voltage. Both of these items replace the 1k ohm/5W resistor that is in the stock amp.

As designed, the power supply filtering in the stock SE84UFO is perfectly adequate for its intended use; speakers. It does hum, but you only hear it if you put your ear up close to the speakers. Not exactly a normal listening position, unless you're weird, or have a very small room. Wink
I had a Taboo II amp a few years ago which, I believe, was the first amp Decware put a headphone jack on, and it had a choke in the power supply.

With headphones though it is quite apparent/annoying. Installing the choke smooths out the waveform B+. Now, using the low impedance output (35-300 ohms), the amp is dead quiet. The high impedance output (300-600 ohms) has an almost imperceptible hum, which is masked if a gnat farts from across the room. I use Sennheiser HD800's btw (300 ohms), from the low imp jack.

With 2.3 watts output, I can only run the volume knob at or below 9 o'clock without going deaf. I can't wait to try a nice pair of planar headphones with it.

With the headphone specific output transformers, this amp is amazing. Very dynamic, but also smooth, with a great soundstage. Personally, I think this is the headphone amp Decware should build. But, that's my humble opinion. :-0

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Brian
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Re: SE84 clone headhone amp
Reply #5 - 04/05/21 at 05:29:03
 
This is fantastic!  It is so much fun to get beautiful sound.  And to accomplish it with your own building adds to the enjoyment.  
I am happy for you.

Brian
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funch
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Re: SE84 clone headhone amp
Reply #6 - 04/19/21 at 03:04:24
 
I have a question about plate voltage on the SV83 tube. Depending on the rectifier I'm using, I measure anywhere from 300 to 338 volts at the plate.
The SV83 datasheet (Svetlana) lists 300 as the maximum plate voltage.
Am I going to ruin my 83's by running over 300 volts?
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funch
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Re: SE84 clone headhone amp
Reply #7 - 05/01/21 at 05:06:10
 
Final configuration. Probably.

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funch
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Re: SE84 clone headhone amp
Reply #8 - 05/18/21 at 02:14:46
 
Being a charter member of the 'Don't-know-when-to-leave-well-enough-alone' club, I of course had to tweak things a bit. (Won't bore you with the details). All of the silver stuff is Dynamat to dampen the enclosure and some of the capacitors.



This amp continues to amaze (no, that word is too weak). Maybe stupefy is better. The only other amp I've heard that gives a similar sound is the Eddie Current Balancing Act, which I owned at one time, and cost more than three times what it cost me to build this. You name a trait (soundstage, impact, separation, detail, yada yada, and this amp has it in spades. 'Nuff said.
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GroovySauce
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Re: SE84 clone headhone amp
Reply #9 - 05/18/21 at 16:14:51
 
What differences did you notice to adding dampening to the chassis? I was thinking about dampening the chassis of my amps. I am concerned about any negatives.

Your build looks really clean, well done!
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Rega P8 | Zephyr MIMC★ | Innuos ZENith MK3 | May KTE DAC | ZP3 25th ZMC1 | ZRock2 25th | EMIA Remote Autoformer | Torii MKIV 25th | Snake River Audio Cables | PAP Quintet 15 1.6 Voxativ Custom XO & SRA cables| Torus AVR15 | Acoustic Treatments
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funch
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Re: SE84 clone headhone amp
Reply #10 - 05/19/21 at 02:23:29
 
Thanks. Mostly I dampened the chassis (the bottom is also damped) because the Hammond enclosures are about half as thick as the stock SE84, and I don't think you can have enough 'deadness'. The Miflex coupling cap's really need it because the way they're mounted, if I tapped one, it would vibrate, and that can't be good. The PS bypass cap's also, but to a lesser extent.

Sound wise, maybe a tad more focused, but that might also be me faking myself out.



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GroovySauce
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Re: SE84 clone headhone amp
Reply #11 - 05/19/21 at 13:20:44
 
For dampening I'm still experimenting. I have found consistent improvement with tube dampers. I've found mass loading components to also have a positive impact. opening the chassis to add some sticky dampening material I'm still hesitant about.
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Rega P8 | Zephyr MIMC★ | Innuos ZENith MK3 | May KTE DAC | ZP3 25th ZMC1 | ZRock2 25th | EMIA Remote Autoformer | Torii MKIV 25th | Snake River Audio Cables | PAP Quintet 15 1.6 Voxativ Custom XO & SRA cables| Torus AVR15 | Acoustic Treatments
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Lon
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Posts: 19603
Re: SE84 clone headhone amp
Reply #12 - 05/19/21 at 13:36:32
 
You can damp a component or tube etc. but dampening it. . .not recommended! Smiley
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HR-1,ZTPRE,ZBIT,ZROCK2,SE84UFO3-25th x2, CSP3-25th.Taboo Mk IV; Rega RP3 w all GrooveTracer mods PS Audio: PST+DSD,P15,NPC,PowerBases,AC-12 pwr cbls, Reference spkr cbls;Mapleshade:Samson V3;;VooDoo:Cremona+Amati intrcncts, Iso-Pods;headphones:PM1,HD800S,ZMF Ori
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HockessinKid
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Re: SE84 clone headhone amp
Reply #13 - 05/19/21 at 14:01:38
 
Personally I'm with Lon, dampening a chassis particularly one of Steve's amps or preamps just doesn't make any sense. There may be some benefit to tube dampers if you have ones that exhibit microphonics.

With that said I did find some benefit to dampening flimsy, inexpensive CD players years ago. Keep in mind these mass produced machines exhibit a lot of vibrational energy and dampening in this situation can help. No such problem with my Audiolab 6000 CDT. This thing is rock solid.

HK
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Nottingham Interspace TT w/ Dynavector 20x2 LO cart + Modwright PH 9.0X phono OR Modwright modded Cambridge CNX V2 > CSP3-25th pre > ZMA-25th amp > PI Audio UberBUSS > Omega SAHO XRS or Caintuck Audio Lii15 Magnum speakers > Snake River Audio & ZenWave cables.
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Lon
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"Love without
guts is
worthless!"
Philip K. Dick

Posts: 19603
Re: SE84 clone headhone amp
Reply #14 - 05/19/21 at 15:39:50
 
Ha, HK I don't necessarily disagree about the chassis, well I do . . . I find benefit sometimes on some chassises. But my point was one can "damp" of do "damping" for vibration and isolation. . . but to "dampen" or do "dampening" is to make things WET. Wink
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HR-1,ZTPRE,ZBIT,ZROCK2,SE84UFO3-25th x2, CSP3-25th.Taboo Mk IV; Rega RP3 w all GrooveTracer mods PS Audio: PST+DSD,P15,NPC,PowerBases,AC-12 pwr cbls, Reference spkr cbls;Mapleshade:Samson V3;;VooDoo:Cremona+Amati intrcncts, Iso-Pods;headphones:PM1,HD800S,ZMF Ori
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Archie
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Re: SE84 clone headhone amp
Reply #15 - 05/19/21 at 16:37:37
 
These replies caught me off guard before I realized the tongue in cheek part.

To be clear, damping (or isolating) components from vibration is generally good and "dampen" also means "to deaden, depress or reduce."   Wink
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ZLC
Technics 1200G TT w/ Ortofon Jubilee MC cart
ZMC1
ZP3 (25th A Mods)
ZR2 (25th A Mods)
CSP3 (25th A mods)
ZMA (25th A mods)
Homemade Big Betsy Speakers (F15s)
Silver Cabling
DIY Isolation platforms under amps & TT.
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GroovySauce
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Re: SE84 clone headhone amp
Reply #16 - 05/19/21 at 16:47:55
 
I read Lons comment as a joke. Cheesy I did go and double check the dictionary though lol.

HK, What is your thought process on why it doesn't make any sense? Using anti vibration footers sometimes makes an improvement. Mass loading components sometimes is another improvement. I figure dampening the chassis might be another area of improvement.
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Rega P8 | Zephyr MIMC★ | Innuos ZENith MK3 | May KTE DAC | ZP3 25th ZMC1 | ZRock2 25th | EMIA Remote Autoformer | Torii MKIV 25th | Snake River Audio Cables | PAP Quintet 15 1.6 Voxativ Custom XO & SRA cables| Torus AVR15 | Acoustic Treatments
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Lon
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"Love without
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worthless!"
Philip K. Dick

Posts: 19603
Re: SE84 clone headhone amp
Reply #17 - 05/19/21 at 16:49:22
 
Ha! Yes, it does also mean that. Neither of these definitions represent something that is good in audio!
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HR-1,ZTPRE,ZBIT,ZROCK2,SE84UFO3-25th x2, CSP3-25th.Taboo Mk IV; Rega RP3 w all GrooveTracer mods PS Audio: PST+DSD,P15,NPC,PowerBases,AC-12 pwr cbls, Reference spkr cbls;Mapleshade:Samson V3;;VooDoo:Cremona+Amati intrcncts, Iso-Pods;headphones:PM1,HD800S,ZMF Ori
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HockessinKid
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Re: SE84 clone headhone amp
Reply #18 - 05/19/21 at 17:27:12
 
GroovySauce,

Mainly referring to applying dynamat or other materials internally to equipment chassis. Sorry, should have been more specific. Also, adding this stuff can reduce resale value of equipment.

I use heavy maple audio platforms under most of my equipment with footers. These do import a noticable improvement in clarity.

Using handi wipes or hosing down electronics ... well I'll leave that discussion to others😁

HK
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Nottingham Interspace TT w/ Dynavector 20x2 LO cart + Modwright PH 9.0X phono OR Modwright modded Cambridge CNX V2 > CSP3-25th pre > ZMA-25th amp > PI Audio UberBUSS > Omega SAHO XRS or Caintuck Audio Lii15 Magnum speakers > Snake River Audio & ZenWave cables.
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4krow
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Re: SE84 clone headhone amp
Reply #19 - 07/18/21 at 22:16:55
 
 I am impressed by the fact that you used quality output transformers in this build. They can have a big influence on the final outcome.

 I agree about the chassis being so thin. I just completed a preamp project with one of these and being OCD, I used big brass braces, silicone and Dynamat, plus added at least a dozen bolts to give badly needed clamping of the bottom cover to the chassis. I likely will not use a Hammond enclosure again. FWIW, in a medium to small enclosure, I found a supplier on eBay that makes a very sturdy chassis for a damned good price. The paint is excellent as well.

 I made a fine headphone amp designed by John Broskie years ago, with the circuit already built by one of the members here and haven't looked back since.
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Decware 34I.3 integrated amp/Forte' 3 bass amp/Velodyne SMS-1 bass mngmnt system/Decware ZOB speakers/Audio Nirvana 8" bass drivers/Xiang Seng DAC/ LR Audio Computer/Rega Apollo R CDP/Emotiva ERC3 CDP/BPT 3.0 power cond.
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funch
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Posts: 127
Re: SE84 clone headhone amp
Reply #20 - 06/19/22 at 01:53:58
 
Made a little upgrade to my amp.





It's now a full blown '25'. I also installed four Tesla glass resistors. The sound is spectacular. Increased dynamics, clarity, resolution. The headstage is phenomenal. [Mic drop].
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