Author Topic: OTL amplifiers  (Read 7398 times)

Offline Tuyen

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OTL amplifiers
« on: August 08, 2014, 02:26:48 PM »
Hello fellow gear heads,

What do you guys know about OTL amps?  What have been your experiences with them?   What are their strengths? What are their weaknesses?

I would like to learn more.

Cheers!

Offline Tuyen

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Re: OTL amplifiers
« Reply #1 on: August 08, 2014, 02:51:54 PM »
This 300B OTL amp by Transcendent Sound looks cool.  More than enough power to run my mids and tweeters.

http://www.transcendentsound.com/Transcendent/300B_OTL_Tube_Amp.html


from my reading online, building a reliable/stable OTL amp is quite difficult though.      Is this true?     I'm thinking if our resident tube amp guru  Paul could build one :D :D

Offline vitavoxdude

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Re: OTL amplifiers
« Reply #2 on: August 12, 2014, 04:32:49 PM »
Good day Mr. T. The amp looks really good and IMO exceptional VFM too, thanks for bringing it to my attention.  ;) I have only ever had the chance to listen to a couple of OTL amps and in each case they left a lasting impression.  Best used with high efficiency high impedance speakers they have very little in the way of an audio signature.  Output transformers in comparison tends to 'sit on the sound' adding some smear and additional weight that when its gone, becomes obvious.  :-X Very fast response and an increased sense of openess and air are all things my brain told me at the time.  Glen Croft (UK) made some good examples for reasonable money.  Using 300b's is expensive but once that palpable sense of realness is heard its not easily forgotten.  Detail also appears in a much more natural way.  IS there any downside, well apart from avoid low impedance loads and keep them ventilated no, particularly with a great tube like the 300B.

With the right speaker match its like comparing a ballerina dressed correctly or dressed in work boots and trenchcoat preforming a elegant fast dance, chalk and cheese.  Not for head bangers who want slow ploddy boom boom and zing zing treble, they do not impress in hifi terms but in musical communication, well they excel along with Decca cartriges and horn speakers. :P

On a side note, I am really keen to get round Steve M's to listen to the direct drive electrostatics as this has a similar trait of no damn output transformers mucking up the sound.


V
We all like different things so lets all agree to disagree and if any common ground is found then worship it.  Mine is the KD hence being present on this forum.

Offline Tuyen

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Re: OTL amplifiers
« Reply #3 on: August 13, 2014, 05:25:01 PM »
Interesting....

Now I think about it, Bryan's stat setup I heard last year and was really impressed with, was using a Tram2 DHT preamp which is an OTL design. Then plugged into the custom OTL power amp.  The system had a very raw, powerful, dynamic, 'direct' type sound.  I did like it. 

Low powered SE OTL amp to drive some horn loaded drivers could be interesting.  Might be too much of a 'good' thing though.

Offline Tuyen

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Re: OTL amplifiers
« Reply #4 on: August 14, 2014, 09:05:54 PM »
I now have a pair of 40W@8ohm OTL monoblock amps that I will try run my whole 3-way horn system from.

The challenge being the creation of a suitable 3-way passive crossover network circuit!     Anyone on here that has experience and can advise?


Offline vitavoxdude

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Re: OTL amplifiers
« Reply #5 on: August 14, 2014, 09:50:35 PM »
Yes agreed, the direct nature and lack of 'bloom' through your Reulit speakers may not be an additive experience and may thin it out too much IMV.  Direct drive OTL's do a magnificent job of untangling complex sounds and removing smear but may appear too 'stark' for some.

BE interested in the outcome.

V
We all like different things so lets all agree to disagree and if any common ground is found then worship it.  Mine is the KD hence being present on this forum.

Offline Tuyen

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Re: OTL amplifiers
« Reply #6 on: August 14, 2014, 10:48:27 PM »
Go the mighty 6C19P tube!   ;D


Offline vitavoxdude

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Re: OTL amplifiers
« Reply #7 on: August 14, 2014, 11:30:58 PM »
So Mr. T, are they in the house or in postage?
We all like different things so lets all agree to disagree and if any common ground is found then worship it.  Mine is the KD hence being present on this forum.

Offline Tuyen

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Re: OTL amplifiers
« Reply #8 on: August 14, 2014, 11:43:29 PM »
They are here, but have not powered them up yet.   Also a friend has lent me his pair of Melody 300B pushpull monoblocks to try as well. http://www.melodyamplifier.com/power-amplifier-5/

Currently on a journey to discover what sort of amp design works best for my system and more importantly, my taste!   :D

« Last Edit: August 14, 2014, 11:50:35 PM by Tuyen »

Offline Tuyen

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Re: OTL amplifiers
« Reply #9 on: August 15, 2014, 12:45:30 AM »
Woah, was googling around and check out MarkOTL's (I think he is a member on here too)  custom modded Transcedent Beast amps.   :o

http://sharksphotos.yolasite.com/

















« Last Edit: August 15, 2014, 12:48:04 AM by Tuyen »

Offline ozmillsy

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Re: OTL amplifiers
« Reply #10 on: August 15, 2014, 01:02:49 PM »
Beautiful looking beasts !
It's all about the music,, not the equipment.

Offline gamve

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Re: OTL amplifiers
« Reply #11 on: August 15, 2014, 01:21:58 PM »
Yep and they sound as good as they look !!!!!

Offline Jehuty

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Re: OTL amplifiers
« Reply #12 on: August 15, 2014, 01:47:59 PM »
Woah, was googling around and check out MarkOTL's (I think he is a member on here too)  custom modded Transcedent Beast amps.   :o

Now you know why he's called Mark OTL. He's a great guy and can build you almost anything you like to perfection  8)
Not all that matters can be measured, not all that can be measured matters.

Offline hedalfa

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Re: OTL amplifiers
« Reply #13 on: August 15, 2014, 03:59:49 PM »
Now you know why he's called Mark OTL. He's a great guy and can build you almost anything you like to perfection  8)

Thats right to think he makes a point of saying he is not an engineer/electrician. Amazing attention to detail, should get an award for the wiring. His worksmans puts may experts to shame...........

Offline kajak12

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Re: OTL amplifiers
« Reply #14 on: August 15, 2014, 08:18:42 PM »
Thats right to think he makes a point of saying he is not an engineer/electrician. Amazing attention to detail, should get an award for the wiring. His worksmans puts may experts to shame...........
You haven't seen SUPRATEK then ;D(ducks for cover)
still discovering the link between electronics and audio reproduction.so much to learn and so little time

Offline Jehuty

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Re: OTL amplifiers
« Reply #15 on: August 15, 2014, 08:28:53 PM »
You haven't seen SUPRATEK then ;D(ducks for cover)

He owned one  ;)
Not all that matters can be measured, not all that can be measured matters.

Offline hedalfa

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Re: OTL amplifiers
« Reply #16 on: August 15, 2014, 08:31:01 PM »
He owned one  ;)

Too scared to look inside :'( :'( :'( :'( :'( :'(

Offline stevenvalve

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Re: OTL amplifiers
« Reply #17 on: August 15, 2014, 09:01:19 PM »
SUPRATEK stuff, they are indeed a rats net, but neatness does not mean it will sound great.

Offline Jehuty

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Re: OTL amplifiers
« Reply #18 on: August 15, 2014, 09:06:12 PM »
SUPRATEK stuff, they are indeed a rats net, but neatness does not mean it will sound great.

That's very true Steve. I like Hedalfa's old Supratek better than Weston Acoustic preamp.
Not all that matters can be measured, not all that can be measured matters.

Offline gamve

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Re: OTL amplifiers
« Reply #19 on: August 16, 2014, 02:33:56 AM »
SUPRATEK stuff, they are indeed a rats net, but neatness does not mean it will sound great.

Yes but it helps a heap if you ever have to trace a circuit to repair it.