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View Full Version : FS Trafomatic 300B power amp.



Metlor
29-11-2021, 11:25
Trafomatic Experience 300b power amp for sale £900.

Excellent condition, really well built, heavy with quality transformers.
Runs almost silently here which is unusual given my electrics.

Had a service approximately two years ago and on recommendation some of the components were upgraded, came back running cooler and performing better.
Very detailed and transparent sounding amp.

The 6sn7 valves are as new, the rectifier and 300b unknown hours to me. The 300b have been marked with pen to indicate position, I can't see any asymmetry in the circuit, but the bias may need checking when fitting new valves ?

I'm in Chesterfield and really prefer not to post this, though would meet up fairly local.

Thanks mart.
https://thumbs2.imgbox.com/11/e5/3MbT5Nhi_t.jpg (http://imgbox.com/3MbT5Nhi)

https://thumbs2.imgbox.com/f6/d7/QPQ5ypQE_t.jpg (http://imgbox.com/QPQ5ypQE)

https://thumbs2.imgbox.com/2a/d5/Qn77floB_t.jpg (http://imgbox.com/Qn77floB)

https://thumbs2.imgbox.com/cd/dd/AXcNGcR9_t.jpg (http://imgbox.com/AXcNGcR9)

https://thumbs2.imgbox.com/62/f0/eARlFdX4_t.jpg (http://imgbox.com/eARlFdX4)

Lawrence001
29-11-2021, 20:59
Have done some research and concluded this is a bargain. Unfortunately I don't have the right speakers to match to it but GLWS.

Pigmy Pony
29-11-2021, 21:28
That does look like a lot of 300b loveliness for the money, GLWS. Forgive my ignorance, but why do speaker outlets have 3 posts each?

Metlor
29-11-2021, 21:40
Thanks all, 4 and 8 ohm taps.

Metlor
06-12-2021, 07:28
Bump.

Metlor
10-12-2021, 15:00
Any interest at £850 ?.

Metlor
17-12-2021, 23:18
Bump.

bumpy
18-12-2021, 11:10
Lovely little 300b amp for anyone getting started on SET amps, but the comments you put about biasing could put off any potential interest with someone not used to valves.

Its a way to get the main valves to run in their optimum range and balanced to each other. Sometime biasing is automatic and other times it needs little pots to be adjusted pretty infrequently using a meter. Its not a big deal

GLWTS

Metlor
18-12-2021, 15:53
Thanks Chris,
I have to say I'm a novice when it comes to biasing valves etc.

It was John Wood in Nottingham who serviced the amp (Just before covid )
He definable swapped out many of the original carbon resistors, and seemed very pleased with how the amp was running.

He was clear that he'd marked the 300b's to indicate their location.
I don't know if this circuit is fixed bias or not, but I assume he has tweaked the bias somewhere to suit the valves ? without putting a meter on it, I couldn't be sure.
With its current valves it is certainly running well and sounding very good.

mart.

bumpy
18-12-2021, 17:13
Was just reading the review here.
https://www.6moons.com/audioreviews/trafomatic4/1.html#:~:text=The%20Experience%20Two%20model%20is %20part%20of%20a,the%20usual%208%20watts%20in%20it s%20data%20sheets.

It states "The amplifier runs auto bias to not require adjustments when changing tubes." So the guy that serviced it went overboard by marking the location of the 300b's, but there was no need to.

I think I read that the amp has C Core transformers which is very good

PeteT
18-12-2021, 17:47
I have to say it is indeed a thing of beauty, love the look of the mixed materials...

If it sounds as good as it looks, someone will be very happy with it...

GLWS

Sent using Tapatalk

Metlor
18-12-2021, 17:49
I think the origins of the company were in transformer manufacture so no worries about the quality there.

The amp is very quiet, almost silent background, but it's not a romantic or warm sounding think to my ears. You hear exactly what's in front.
Probably suit someone with a good vinyl set up who listens to two or three albums a day.
When I can I have music on 10 hours or more, seems excessive (and costly) running power valve that long ?

petrat
22-12-2021, 09:33
I had the integrated version of this amp (which just has a passive pre section), and it was really a very nice 300B amplifier. I actually used it as a power amp, with the volume control wide open, and it had a very clear and transparent sound to it ... as Martin says, it's not a soft and cuddly 300B like some. Trafomatic do indeed design, manufacture and sell transformers, which undoubtedly explains the lack of 'roll off' at the frequency extremes. For anyone that might be concerned that it has been modded, I wouldn't be, as John Wood is one of the best valve amp guys in the UK. This really is a bargain.

Sixty2
23-12-2021, 08:57
I’m surprised this amp is still here! I owned the integrated version and used it with various 300B’s, including Western Electric. Fabulous amp - not really too sure why I sold it! Echoing what Peter says, this is a bargain.

Metlor
24-12-2021, 13:57
Thanks for the positive comments fellas.
Wow, Western Electric !

I've had a few offers but I'm really selling (this and other stuff) to fund my curiosity and try other gear !
:)

Metlor
04-01-2022, 18:18
New year bump.
Now available for £800.

Metlor
12-01-2022, 23:37
Bump.