OTL AMPS

[loheswaran]

Dear All

Anyone here use an OTL amp? I am thinking about:

Einstein
Berning
Atmashere
OTL's

BTW they are the only otl designs I know of - if there are others please let me know.

or else a Tom Evans Linear B

experience and feedback would be appreciated

[Ali Tait]

Yes, used and built a couple of the Transcendent Sound kits. Excellent amps if you have suitable speakers.

[Jazid]

Transcendent are the obvious company missing from your list, and well liked by those with experience of them.

Nice idea but OTLs are chock full of compromises (like all amps), particularly output impedance is usually rather high, so need careful partnering with suitable speakers to give their best.

Ha! Beaten to it [emoji16]

Sent from my BLA-L09 using Tapatalk

[Firebottle]

Yes designed and built a few OTL's.

Also remember they are very inefficient, they take a lot of power to produce not much output.

[Ali Tait]

But they sound very good. :-)

[User211]

Atma-sphere M-60.

This amp sounds plain strange to me. Spent a few hours with a pair on some horns.pl FP15s after hearing them sound odd at Munich on some horns.

Those particilar examples are highly coloured with odd spacey imaging I think.

[anthonyTD]

Valves are high impedance devices, and therefore not designed to be directly connected to a speaker output, which as others have stated, the output impedance is always going to be reletively high with respect to conventional valve amps with an output transformer, and certainly compared to any solid state amp!
A...

[hornucopia]

Both Tom Evans and the Berning amp are highly rated, but aren't OTL. I certainly liked the Berning I had on loan once. Both pricy.
On a different angle, the Pass F series are pretty stripped back in design and sound valve-like (reputedly)

[Ali Tait]

Valves are high impedance devices, and therefore not designed to be directly connected to a speaker output, which as others have stated, the output impedance is always going to be reletively high with respect to conventional valve amps with an output transformer, and certainly compared to any solid state amp!
A...

The TS Son Of Beast as an example has a quoted output impedance of 0.8 ohms.

[AD Audio]

I built some Transcendent Audio Pinnacles for a client. As sold the design is dangerous and does not meet UK electrical safety requirements (or any sensible, safe use) and some of the components were under-rated for a relatively common event-fuse failure on one leg of the output valves. While both issues were relatively easy to solve and correct, I was also under-impressed with the overall look of the amp for its price. All this might be worthwhile but to have 8 300bs producing 6 watts into 8 ohms is pretty extravagant!
It might be worthwhile if the sound quality was out of this world and you have some super-efficient speakers but while SQ is excellent there was nothing there that is not bettered or equalled with a well-designed SE valve amp.
David

[anthonyTD]

But how many valves does it use in the output stage to get that figure, and how much useable power do you actualy get for all that heat!;)
The TS Son Of Beast as an example has a quoted output impedance of 0.8 ohms.

[krugdoktor]

I‘m using the german made Eternal Arts OTL https://audioclassica.de/de/EternalArts-OTL-Mark-2.html into my QUAD ESL 57 QA https://www.quad-musik.de/index.php/de/produkte/elektrostaten/esl57-qa and it‘s a match made in heaven. Lots of power and clarity!

[Ali Tait]

But how many valves does it use in the output stage to get that figure, and how much useable power do you actualy get for all that heat!;)

4 per channel, and consumption is quoted as 0.7A, giving a quoted 15w/ch

[jahsavage]

Graaf have been making OTL amps for a few years so you may be able to pick one up for a sensible price.

Here's a review

https://www.stereophile.com/tubepoweramps/997graaf/index.html

[anthonyTD]

:)
Is that .7A per channel, or total consumption, ie both channels ?
4 per channel, and consumption is quoted as 0.7A, giving a quoted 15w/ch

[anthonyTD]

No worries, just found the info on them! :)
A...

[Ali Tait]

Not efficient by any means, but they do sound good. I had a 4w Mini Beast that did deeper and better bass than any SS amp I’ve tried.

[loheswaran]

So as you are aware:

current amp LAvardin IT
Speakers - Roksan Darius s11 (impedance drops to 4ohm) but actually easy to drive

I have a near field set-up - I need more load tolerance than I do outright power.

I have to say single ended is beguiling, but I've always found the bass a bit sloppy.

I like my IT but have had it now for 17 years - I did upgrade to V2 specs. I think it's time for a change - I am looking for a tad more warmth to come through

[anthonyTD]

Indeed, also; i asume the over-all feedback must be quite high to acheive the output impedance figures quoted!
Either way; there are no perfect amplifiers, speakers, source equipment etc, so what ever works for a paticular system, and personal taste, is what this hobby is all about. :)
Not efficient by any means, but they do sound good. I had a 4w Mini Beast that did deeper and better bass than any SS amp I’ve tried.

[User211]

Not efficient by any means, but they do sound good. I had a 4w Mini Beast that did deeper and better bass than any SS amp I’ve tried.Driving?

[Ali Tait]

At the time, some Zingali Overture 2, also some Millburn II, one of Colin Topps’ creation. Last but by no means least, Impulse H2.

[paulf-2007]

Assuming you have efficient speakers so forget hot valves using loads of power, get your hand in your pocket and buy a Bakoon amp, solid state with set sound and excellent bass grip. Best amp I ever bought and it's not going anywhere. I tried the transcendent mini beast in my office and it was nice but very hot, hotter than most valve amps I've had with the exception of 6C33C push pull. Try to get a listen to an OTL in your set up. Where in London are you.

[southall-1998_mk2]

What does an OTL amp sound like? Never heard any.

S.

[Ali Tait]

Generally very clean and clear, huge soundstage and great bass. You need suitable speakers though.

[Bencat]

Quite surprised that no one has mentioned the Croft OTL's they are one of the few modern amps that were in production for a while (not sure but do not think they still make them) . I bought a Croft OTL just after the Wam Show in 2019 after hearing it in one of the rooms. I have always considered it an ideal match for my Quad ESL57's . Only problem has been that the current owner lives down Dorset / Cornwall way while i live up North in Liverpool .

So I will be getting the Croft this month at the 2020 Wam Show and then bringing home to meet its new friend Quad . Should be quite a party and will hopefully lead to a musical partnership that will make me very happy .

[AD Audio]

I'd forgotten that one. 2 years ago IMO driving some Rogers with an Oppo Sonica it stole the show!

[loheswaran]

Quite surprised that no one has mentioned the Croft OTL's they are one of the few modern amps that were in production for a while (not sure but do not think they still make them) . I bought a Croft OTL just after the Wam Show in 2019 after hearing it in one of the rooms. I have always considered it an ideal match for my Quad ESL57's . Only problem has been that the current owner lives down Dorset / Cornwall way while i live up North in Liverpool .

So I will be getting the Croft this month at the 2020 Wam Show and then bringing home to meet its new friend Quad . Should be quite a party and will hopefully lead to a musical partnership that will make me very happy .

I had not even thought of Croft - thanks. I would love a bit more British kit on my shelves - always nice to support UK manufacturing where possible