One more 4P1L SE - Page 46 - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 18th January 2013, 06:36 PM   #451
regal is offline regal  United States
diyAudio Member
 
Join Date: Jan 2004
Location: MD
Quote:
Originally Posted by Pano View Post
It does if the transformer has the right ratio, which is (I suppose) what you meant. The voltage out of the 4P1L is going to be stepped down thru the transformer anyway. Might as well step it down to the ratio you need, right?
Well the Ra of the 4p1L isn't particularly low, so you need quite a bit of inductance, and you need to step down to 38 ohms. So you are looking at a 5k:38 OPT. So 11.5:1 ratio. Two watts into 38 ohms is 288 Vp-p across the primary, no way the 4P1L can swing that without A1/A2 and hitting the ugly portion of the curves, imho anyway you look at it its not a big enough "upgrade" to my 6c4pi/5842 spud amp.

Quote:
Originally Posted by Pano View Post
Is damping factor really that important with most headphones? Maybe with the ear speaker type, but with more normal headphones
damping factor effect depends on the headphone driver design. Most modern headphone drivers have been "tuned" to modern SS <2 ohm opamp output impedance.

Simple tests which have been done adding resistors in series have been shown to change the frequency reponse. Not saying its black and white, but damping factor is an issue in how the transducer reponds to power.

The biggest issue as a tube guy is all the signal loss with a high DCR windings, its just that much harder the output tube has to "work", more distortion. And headphones reveal it.
  Reply With Quote
Old 18th January 2013, 06:53 PM   #452
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Milliways
Blog Entries: 4
Quote:
Originally Posted by regal View Post
So 11.5:1 ratio. Two watts into 38 ohms is 288 Vp-p across the primary
OK, but I see only ~9V needed for 2W peak into 38 ohms. Or 206V P-P on the primary. That just details. Whatever the output impedance of the OPT, 2W is going to be pushing the 4P1L, agreed. Wavebourn seems to indicate it's OK up there, but I've not pushed it that far yet.

Honestly, I don't want headphones that need two watts to function. My speakers hardly need that! If I did like them, I guess I'd do like you and go for a more powerful amp. My OPT has a 600 ohm winding, might be interesting to hear what that sounds like on 300 ohm cans.
__________________
Take the Speaker Voltage Test!
  Reply With Quote
Old 18th January 2013, 06:58 PM   #453
iko is online now iko  Canada
diyAudio Moderator
 
iko's Avatar
 
Join Date: May 2008
Location: Toronto
Quote:
Originally Posted by Pano View Post
Honestly, I don't want headphones that need two watts to function.
+1
  Reply With Quote
Old 18th January 2013, 08:11 PM   #454
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Quote:
Originally Posted by regal View Post
no way the 4P1L can swing that without A1/A2 and hitting the ugly portion of the curves, imho anyway you look at it its not a big enough "upgrade" to my 6c4pi/5842 spud amp.
Huh? Which ugly portion of the curves? I'm asking once more: did you ever dare to read the topic from the beginning?

I started this topic to share with you how I got 2.5 W of pristine clean power from one 4P1L tube, and 5W from 2 in parallel, why start again from common musings about common tubes according to common beliefs?

Nobody needs 300 Ohm secondary to drive 300 Ohm headphones that need milliwatts of power. But to drive 50 Ohm 2 W you indeed need 50 Ohm secondary. To drive 32 Ohm 2 W you need exactly 32 Ohm 2W secondary. To drive 5W 50 Ohm headphones you need 2 tubes in parallel and 50 Ohm secondary transformer.

By the way, I found a company in Russia that will make me 32 and 50 Ohm 2 and 5W transformers for headphones. Stay tuned.
__________________
The Devil is not so terrible as his math model is!
  Reply With Quote
Old 19th January 2013, 04:51 AM   #455
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
I don't see here any "ugly portion of curves". Up to +16V in class AB2 they look nice. As I said, in AB2 driving up to +12V I was getting 2.5V from the tube. In A1 only output power can be obtained around 1.8 W from tube. Why I made the A2 capable, because it's hard not to hit positive voltage on control grid of the output stage on peaks, that means non-linear grid current, rectification of signal, and dynamic change of bias point.

Here again, triode curves that show how nice is the tube when driven in class A2 mode:

Click the image to open in full size.
__________________
The Devil is not so terrible as his math model is!
  Reply With Quote
Old 19th January 2013, 07:36 AM   #456
FLT is offline FLT
diyAudio Member
 
Join Date: Nov 2009
Quote:
Originally Posted by Wavebourn View Post

By the way, I found a company in Russia that will make me 32 and 50 Ohm 2 and 5W transformers for headphones. Stay tuned.
Nice to hear...
What about output transformers for power amps?
I always wanted to build an "all-russian power amp"

regards...
  Reply With Quote
Old 19th January 2013, 10:58 AM   #457
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
Quote:
Originally Posted by Wavebourn View Post
Huh? Which ugly portion of the curves? I'm asking once more: did you ever dare to read the topic from the beginning?

I started this topic to share with you how I got 2.5 W of pristine clean power from one 4P1L tube, and 5W from 2 in parallel, why start again from common musings about common tubes according to common beliefs?

Nobody needs 300 Ohm secondary to drive 300 Ohm headphones that need milliwatts of power. But to drive 50 Ohm 2 W you indeed need 50 Ohm secondary. To drive 32 Ohm 2 W you need exactly 32 Ohm 2W secondary. To drive 5W 50 Ohm headphones you need 2 tubes in parallel and 50 Ohm secondary transformer.

By the way, I found a company in Russia that will make me 32 and 50 Ohm 2 and 5W transformers for headphones. Stay tuned.
The Russian company will make 300 ohms transformers?
  Reply With Quote
Old 19th January 2013, 11:03 AM   #458
regal is offline regal  United States
diyAudio Member
 
Join Date: Jan 2004
Location: MD
Quote:
Originally Posted by Wavebourn View Post
Huh? Which ugly portion of the curves? I'm asking once more: did you ever dare to read the topic from the beginning?



By the way, I found a company in Russia that will make me 32 and 50 Ohm 2 and 5W transformers for headphones. Stay tuned.
Ugly is a harsh word, its just that with orthodynamic headphone they have much lower itrinsic THD than speakers so you hear distortion much easier. The 4P1L is extremly linear over all. I just can't seem to explain that its Ra is not low enough to drive an orthodynamic driver 25Vp-p, but thats OK its an unusual situation.

If you find a transformer winder please do share, I too am interested in an all russian tube amp.
  Reply With Quote
Old 19th January 2013, 11:46 AM   #459
stajo is offline stajo  Sweden
diyAudio Member
 
Join Date: Jun 2011
Location: Stockholm
Quote:
Originally Posted by regal View Post
If you find a transformer winder please do share, I too am interested in an all russian tube amp.
200:ish would be my choice as I have a pair of DT 931. Heres a little infosite on headphones. Pretty nifty. Meier Audio

Staffan
  Reply With Quote
Old 19th January 2013, 12:50 PM   #460
regal is offline regal  United States
diyAudio Member
 
Join Date: Jan 2004
Location: MD
Quote:
Originally Posted by stajo View Post
200:ish would be my choice as I have a pair of DT 931. Heres a little infosite on headphones. Pretty nifty. Meier Audio

Staffan

Great summary of what I was trying to comnumicate, now imagine headphones with specs like 32 ohms 98 dB/mw, or 600 ohms 94 dB/mW or 50 ohms 87 db/mW all tuned for different output impedance, all "liars" on their specs, and all offering lower distortion greater transperancy than the most expensive hand crafted speaker.

Then you see that you really need to "customize" your 4P1LE SE OPT to match your headphone of choice.

With the 4P1LE output it would power 90% of the all the high end headphones with the right output transformer. But its lower voltage rules out some orthos like the HE6 with its super strength rare earth magnet,AKG K1000's, and it rules out electrostatic headphones of course.

Senn and Beyer guys are lucky because those headphones match well with preamp configurations.

But as a positive the 4P1LE's lower plate voltage offers the opportunity to parafeed, imagine a nickle permalloy OPT for headphones, I would love to hear such a thing.

There is also the MGM engineered peerless tl404 autoformer, probably the only output iron really designed for headphones. But if anyone finds a pair I get first dib


Amonst all this discussion about impedance matching we mustn't forget that sensitive headphones must have a black background, no 60/120/180hz hum or buzz at all, my rule of thumb for Grados is that stuff has to be -90dB down.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
pentode in triode mode SE vs a DHT SE like 2a3/300b jarthel Tubes / Valves 67 8th July 2014 01:51 AM
Russian-English Translation of 4P1L datasheet 316a Tubes / Valves 16 6th September 2011 12:09 AM
Rare audiophile stereo tube SE amplifier DIY kit (6C2C + 4P1L). mik190 Swap Meet 7 1st November 2010 07:59 AM
Can the Golden Tube Audio SE-40 SE drive 16 ohm woofers? nelsondog Everything Else 1 11th November 2007 05:00 PM
Parallel SE vs. Single SE Output Question valveitude Tubes / Valves 19 4th May 2005 05:36 PM


New To Site? Need Help?

All times are GMT. The time now is 02:53 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2