![]() Sowter Audio Transformers (E A Sowter Ltd.) |
|
|
CUSTOMER COMMENTSHere are some comments you have made. We only publish comments with the author's permission.
From: Steve Lawrence [mailto:s.j.lawrence@mypostoffice.co.uk] dear Ruth, PS * I recently used a Chord Symphonic fully balanced phono stage at home and I believe that using your transformers has bettered that. From: gianpaolo.lanza@sanita.padova.it [mailto:gianpaolo.lanza@sanita.padova.it] Dear Mr Sowter, I'm ready to give you the FFT results about the parallel of two TDA1541A and your output transformer 8347c. The transformer was loaded with 33Kohm and the TDA1541A with 18.2ohm. The output DAC current with this load is 7.5mA while the output voltage is 38mV peak to peak (13.2mV rms). At the secondary is present about 180mV rms, surely not an high value but enough for drive a good valve preamplifier. Paolo
Dear Brian Your new custom Marshall DSL 50 output transformer is fooking great. The amp has so much more chime in the clean chords as well as giving a noticable increase in the low frequency performance for down tune dirty stuff. No longer does it sound strangled and thin at high volume, it just wails now at all frequencies so feedback is much more controllable with good pickups and all the harmonics are there now real strong. I am biasing it at 40mv instead of the marshall spec at 45 because it has even too much snap at 45 and 40 just softens its power delivery enough for plenty of edge in the tone but not too much. Only improvement to the kit would be to add another 2 inches to the primary leads to make cable routing very slightly better. Thanks for all your help its now made an amp that is finally really worth putting a mic in front of, as the old JCM 800 used to eat it for breakfast, but not anymore. Regards.•:*¨¨*:•. ¸¸.•´¯`•.Mark Fairfax-Harwood, Engineer Springvale Studios __________________________________________________________ From: Sergei Klimanski [mailto:ks@ksan.lv] Dear Brian, Finally I completed my SE amplifier ( tubes are Aa Valvo - 4613 Pope ) with output transformers as per your advice, and with your 8920 transformers as input. Frankly speaking, I have got best sounding amplifier I have ever heard. Sergei Klimanski From: richwalters@bluewin.ch [mailto:richwalters@bluewin.ch] All qualify for that Christmas Turkey. Rich
From: kees van de wiel [mailto:kvdwiel57@hotmail.com] Hello Brian, From: michelemercatali@virgilio. Hi,I'm Michele Mercatali, a few days ago I bought 2 9580 sowter,I would
like to thank Kind Hello Brian Kind regards Giovanni Cornara
Via Aleardo Aleardi 14-2 35122 PADOVA ITALY From: Jan Erling Veiset [mailto:] Hi Brian, I'm now testing the unity amplifier and the trifilar transformer performs very well. The amps are basically built from the attached revision of the schematic and the front end is a common cathode + split load phase inverter based on E80CC.
Working conditions are 260V B+, 190V Bg2 (regulated) and –90V for the negative rail. The amp runs near to class B, biased with 4 x 10mA in the output stage. Max power output was estimated to be about 30W and I measure the onset of clipping at ~15Vrms into 8.2R (~28W)
Global feedback is kept low, about 10dB, but there are no problems to apply more feedback to get even better technical results. Personally I am not a big supporter of global NFB, but used in proper amounts it does good things.
With 10dB NFB I achieved these results: Zo : 0.8 ohm THD: 0.6% (30Hz, 1kHz, 10kHz, 25W Po) (2nd and 3rd harmonic dominant) Freq resp: 10Hz -100kHz (+0/-0.5dB). –3dB at 230kHz.
With feedback there was no major peaks or dips in the frequency response. There was a small, low Q peak at ~100kHz (+0.8dB) but with 24pF in parallel with the feedback resistor the response turned out to be straight as an arrow up to 100kHz. The attached square wave is 30kHz, quite astounding for a tube amp.
All in all, this project ended up with the best frequency response I ever have seen in a tube amp with output transformer. Thank you for superb transformers!
Best regards, Jan E Veiset Norway
Hi Brian Just to let you know I installed the TVC today and the results are superb. This is like changing a major component in the system! The most obvious difference is the ease of the sound, the complete lack of hardness, grain, and edge, even on CD. I was already using a high quality Grayhill attenuator with Holco resistors, in a shunt arrangement in my passive, but your transformers have transformed the sound (sorry! but it's true...). The naturalness, dynamics and liquidity (not just in the midrange!) of the sound are staggering. And when things get loud, the sound does not harden or change, it just gets loud... In my opinion every serious audiophile should hear and buy these TVC's, because a resistive volume control adds so many deleterious artefacts and subtracts so much subtle information, this is so blatantly obvious now. I am overwhelmed by the change. I expected a subtle improvement, not a transformation and huge improvement in sound in an already very high end system. Regards, Mike Kontor From: stevecresswell@mac.com Date: 3 September 2007 13:07:00 BDT Hi Brian, Just a note to say I installed the push-pull output transformers on Friday. They provide the perfect finishing touch to the retro 50s style 6AS7 amplifier I have been working on for the past couple of months. What can I say? The output transformers have replaced a pair of Hammond 125Ds and have taken the performance of this amp to another level entirely! To talk about veils being lifted and instruments appearing from nowhere would be to fill this email with cliches. But it's perfectly true. Most people would be satisfied with this but even better is the full-bodied, clean, dynamic and effortless presentation these transformers give. No congestion at higher levels and zero listening fatigue.
Excellent service and turn around time too. Fantastic! Kind Regards Steve Cresswell From: Carlo Balestrazzi Sent: Thursday, May 03, 2007 9:45 AM Subject: A couple of Sowter transformers
Dear Sirs, my name is Charles Balestrazzi, I live in Italy and am 47. It means that 30 years ago I saw an advertisement on "Wireless World" of your Company, and decided to order a couple of your output transformers for EL34 PP, for my home made amplifier. I was 19, now 47, as I said, and that amplifier has run for 28 years without any problem, your transformers has given a pure warm enjoyable sound ALMOST EVERY DAY of my life for 28 years. I've substituted valves, resistors, diodes, capacitors, one choke, speakers, but your transformers are still young. Friends of mine that possess tube amplifiers are used to say that my one is particular, because it has got the force of a push-pull and the details of a single ended. I use general feedback, cum grano salis. Thank you very much.
Carlo Balestrazzi
From: Luca Sfarzo [mailto:luca.sfarzo@fastwebnet.it] Hi Brian, I am writing you this email after having bought some time ago (about 2months) a par of 9570 and after having put them to play for about 80 hours in a World Audio Desing Phono II DIY pre-phono. I have to say that it has been a very very fine choice buying and playing your amps; They are stepping-up a Benz ACE/SME3009S2 (rewired)/TD160 LP machine and the sound is really detailed, clear and, above all, they allow the system to give that ?live? sensation of being just in front of an orchestra playing the Beethoven 9th Symphony.. Least but not last they are very quiet; they add no hum at all and I find that it is a very remarkable feature. You can find attached a jpeg of the work I did. Next step could be trying some sowter transformers in my wad kat6550 power amplifier...not so far in the future. So thank you for your support. Best regards, Luca Sfarzo Italy
Hi Brian, I just installed the new transformer in the RCA BA6A and the unit is working excellently now. I was able to get a perfect balance out of the vari-mu tubes. Thanks for all your help. I tried to get the original out of the can but gave up on all that black wax goo holding it in there. I ended up using washers to clamp the new one to the edge of the empty hole in the chassis where the original was. Best, Chip Verspyck Tech It Out Inc. From: Lukasz Fikus [mailto:lukasz.fikus@wp.pl] Dear Sowter, I hate you for what you have done to me. Your transformers are so addictive Thank you. Lukasz Fikus -----Original Message-----
From: "gianni cornara" Date sent: Tue, 25 Apr 2006 18:55:46 +0200 Dear gents, I completed all tests on my guitar amplifier which utilizes a U072 OPT. www.giannicornara.net Kind regards Via Aleardo Aleardi 14-2
From: "peter carmichael" <peter.carm@virgin.net> To all at Sowter Transformers I want to say how pleased I am with the two Sowter 9545 DAC Interface Transformers you supplied me with. a) Audiocom Superclock 3 with power supply. b) Audiocom Invisus regulators for 3.3 volt supply. c) Added an extra Burr Brown DSD1792 DAC to convert the main two channel digital audio signals. d) Used the two Sowter 9545 transformers to provide a new two channel audio output from the new DAC. The circuit is basically that of the DAC Passive Output Stage described at www.raleighaudio.com. I have added some circuitry to reduce the DC through the transformer primaries. e) Added a new analogue analogue power supply with Walt Jung super regulators to feed the analogue supply pins of the new DAC and the DC reduction circuitry. The DAC design described at www.tentlabs.com was useful here. The sound from the modified player has improved dramatically. So dramatically in fact that I have had to change my ideas about the audio sound quality available from digital sound sources, especially penny plain CD. Vinyl disc replay now seems a poor relic from the past. my very best regards Peter Carmichael
From: shivrajsingh@touchtelindia.net Date sent: Wed, 07 Dec 2005 15:44:28 Subject: THANK YOU To: sales@sowter.co.uk Hello Ruth, Convey my gratitude to Mr. Sowter and Mr. Brian Last. Best Regards Shivraj Singh.
From: y.mahe [mailto:yannig.mahe@gmail.com] From: aronsson [mailto:nossnora1@hotmail.com Sent: 23 February 2005 19:50 To: Brian Sowter Subject: Thank you! Thank you Brian! I ordered a custom mains transformer and a pair of plate chokes to my Quad amps. Your build quality exceeded my expectations and everything was professionally packed! I'm very satisfied with your service! Best regards Pontus Aronsson, Sweden Date sent: Wed, 23 Feb 2005 23:46:55 +0000 Subject: Re: Martin Thain - order From: Martin Thain <martin@lashed.net> To: sales@sowter.co.uk Hi there, Now got my transformers installed and working nicely. Sounding excellent and getting better every day as they run in a bit more. Quite a bit more of an improvement than expected - missing bass octaves have appeared, previously unintelligible lyrics can now be heard clearly, and my cat no longer feels the need to leave the room when I turn up the volume... Many thanks for an excellent product Martin I have attached some pictures of the 8995s 'in situ'
From: AUDIER [mailto:audier@bird.nl]
Sent: 25 November 2004 18:42 To: Brian Sowter Subject: transformers Dear Brian, I don' t know if you did the transformers all by yourself because they are 200% perfect. You was talking about decreasing the Freq. characteristic by making the ratio to big. I can tell you, with this quality of transformers there is enough room thanks very much, Regards to Brain Last (but not least) and Ruth who had so much patience. I have no problem at all if you use the email I sent you, perhaps it has sense to add to it that it was very difficult for us to find someone who has still the knowledge to make this special transformers for pro vintage limiter / compressor because it is very critical. till next order. Jan Audier Fom: "Len Edwards" <> To: <sales@sowter.co.uk> Subject: Re: G.L.Edwards - order Date sent: Tue, 12 Oct 2004 18:00:50 +0100 Ruth Just to thank you for the transformers, received bang on the time Many thanks from a happy customer Len To: "'sales@sowter.co.uk'" <sales@sowter.co.uk> Date sent: Sun, 3 Oct 2004 14:06:07 +0100 I have completed installation of the 8983 and find them to be everything I was looking for. Powerful peaks remain perfectly clean (and very powerful). Bass is remarkable. Following is a note I posted on the SET portion of audioasylum.com.www.audioasylum.com/forums/set/bbs.html I continue to find the transformer's performance impressive. It facilitates the full dynamic capability of my 2A3 SET amp, making possible playback of orchestral and rock selections that sounded compressed with other transformers. Leo Keightley ---------------------- "It's a little hard to find reviews of the Sowter parafeed transformers, so I'll add to the small list. I installed a Sowter 8983 in a 2A3 SET. I was able to purchase the 8983 (5KOhm primary) with a single 8Ohm output. I prefer a higher primary impedance than the 2.5KOhm that seems to be prefered by many for the 2A3. Until now I've been using Magnequest parafeed transformers. I originally had a cobalt Magnequest (2.5KOhm in, 8Ohm out), but never really liked it. The variations in speaker impedance of my RF-7s and Chorus-IIs caused frequency peaks and gaps. I purchased a 5KOhm primary (1.5Watt) Magnequest and the sound completely smoothed out. Great for quiet stuff, but some compression at higher volumes. I selected the Sowter because it has plenty of power capacity (about 10 Watts) and the I/O impedances I found so successful with the smaller Magnequest. The Sowter does indeed handle power peaks much better than the under-sized Magnequest. Extension is very good top and bottom, and detail is fine. I recommend the Sowter to anyone looking for a little more headroom than the 1.5 or 3 Watt Magnequests. I've kept the Magnequests in the amp for quieter selections and can select either transformer with a switch (speaker cables have to be moved to alternate posts)." Leo From: John Lumsden [mailto:john@johnlumsden.com Sent: 14 September 2004 16:53 The amplifier sounds superb also. Best Regards, John From: Vinicio G. [mailto:vgusv@yahoo.com] Sent: 10 September 2004 21:29 To: Brian Sowter Subject: RE: Help in my stereo to mono design Hello Brian, I just received the 8920 (first I will try with the stereo to mono conversion). I just connected the 8920 to my SRPP 45 SE amplifier . Now I'am listening Turandot with Shutterland and Pavarotti from my turntable, I'm impressed. There are subtle details from the vinyl that where lost. Now I switch to Gould on CD (playing Orlando Gibbons),my words are lost. Another change, to Blandine Verlet plying Froberger, a CD named "Froberger ou l'intranquilite'. Well, my english is not sufficient to express how the sound change, to express how I feel the music. The harpshicord seems to be in my room. Thank you very much for your fast an reliable service. Now it's time to try the 9335. Soon I will order it, Best regards Vini
From: bert [mailto:hb044952@belgacom.net] Sent: 19 July 2004 21:33 To: Brian Sowter Subject: Re: info wiring thanks for the help with the info about the transformers! last week i was working on a film set in Belgium and the monitor from the lighting director made a 50Hz hum on the sound lines even after two days he did not want to believe it was his monitor causing a lot of trouble for the sound crew ! with al the transformers i found in the dump and earth lift and battery power and al the tricks ,we end up the week of working day and night it was a hell!!!! and that's why i want to thank you for your quick answer..... this is proffesional! and i apreciate this after a week of..f........ i am happy to see somewhere people take there job seriously!! thank you!! bertje@belgacom.net location sound assistant
From: Yury Gelgor [mailto:yury_gl@hotmail.com] Sent: 18 May 2003 05:11 To: support@sowter.co.uk Subject: Thank you for 9336s Dear Mr. Sowter, Your 9336 sound just great. I couldn’t even imagine that replacing of Caddock resistor attenuator with such input transformer improved amp sound so much. http://www.geocities.com/yury_g/ You can use link to my site or amp schema any way you like. DAC is still a project and not completed yet. I DO appreciate your business. Thank you Yury Gelgor Kansas City, USA Date sent: Tue, 11 Feb 2003 11:08:49 +0000 From: "Carrick, M. (Mike)" <mcarrick@ford.com> To: sales@sowter.co.uk Subject: Big Thank you Thanks for the mains tx and chokes, received Friday. I got the preamp finished over the weekend but only got as far as electrical checks on Sunday evening; anyway, last night I listened and wow, this beauty is *good* ... very, very good and musical. I know that power supplies are absolutely crucial in valve hifi. This preamp uses two stage pi filtering with the second stage split left/right channels .... hence my somewhat specialised needs, which you met; thank you! Rectification is by television damper diodes (6CJ3) which have *massive* voltage and current ratings, with extremely low voltage drop and 'clean' performance. I'm sure I'll be coming to you for more things in due course. Regards Mike Carrick
-----Original Message-----
From: Aristidis Coumpas [mailto:arco@otenet.gr]
Sent: 31 March 2002 19:00 To: Brian Sowter Subject: Re: AC-ACPWR-110302 MAINS TRANS SPECIFICATION Dear Brian, I know it took some time, but here is the result and I tend to believe that your "iron" (as the Americans say...) has a lot to do with the wonderful sound heard through my horns!
Thanks again for all your patience and understanding,
Aristidis
Dear Brian,
I finished my preamplifier using pair 9335s and 3575s and it sounds fantastic! I wanted to share some photos with you. One is attached below and more you can find at:http://www.pbase.com/mirkot/preamplifier
Please feel free to use them as you wish.
Sincerely,
Mirko Trifunovic
Toronto, Canada
.........Let me tell you also that I find your 'Neve transformers' absolutely amazing. I built a 1272 and I compared with the original. I did 24 tracks with both of them (2 songs, same one). When it was time to mix these songs, I found that the tracks I did with your transformers were adding to each other really better than the ones with the original Neve. The mix had punch and no 'fog'. Really nice !
Thanks for your help
De José Cédric
<Sound engineer & Studio manager
Au Pairon, 57
4831 Bilstain-Limbourg
BELGIUM> www.triskelstudio.net
From: "Julian" <julian@cactusorchard.freeserve.co.uk> Dear Brian,
Last week I enquired about the possibility of you supplying some transformer and choke shrouds in order that I might smarten up my old valve amplifier. The shrouds have now arrived, they're a perfect fit and exactly what I wanted. I have been so impressed with the friendliness and good service during my dealings with Sowter that I feel I must write to say thanks. I was beginning to wonder if I would ever find a source for the shrouds as I had drawn blanks with the sheet metal pressers that I had approached, and the response from certain other transformer manufacturers was a curt "We do shrouds for our own transformers only. Goodbye". Your service is all the more impressive given that my order was so tiny and almost irrelevant to your manufacturing. Even your protective packaging for transit in the mail was done very thoroughly. Please pass my compliments to all involved in my little order. You are a great company. Many thanks, Clive More Dear Brian, Date: Sun, 19 Dec 1999 19:38:44 +0100 Dear people at Sowter I build 2 Sowter 8347 transformers into my Denon 1000 minidisc-recorder which I also use as digital to analog converter. I am very pleased with the results. It sounds are so much better then with the build-in opamp analog output. My friend didn't believe his ears. What have you done, what have you done?............ Congratulations with such fine product. I will certainly use more Sowter transformers in the future! I am an enthusiastic Tube-amp builder myself. Many greetings from the Netherlands, Dick van de Merwe triode.dick@wxs.nl From: "J. Claessens" <j.claessens@chello.nl> Dear Mr Sowter, ...........I also tested the Neve preamp I made with your transformers. Thanks !! Dennis Claessens From: "Graham Tricker" <gt.audio@tesco.net> Dear Brian http://www.gtaudio.com From: "Noble, Jonathan, Mr" <013NOJ@cosmos.wits.ac.za> Your IT is doing a great job! With Brave Ulysees and the Ariel loudspeakers (92 db sensitivity) I get a huge 3D sound. On some recordings I get a height illusion, with sounds that seem to eminate from above the ceiling. P.S. My friend wants me to build him a pp300B, so I will send that order through to you, hopefully some time this year. Best Regards From: "Bruno Dal" <brunodal@mail.bip.net> Date sent: Thu, 8 Apr 1999 22:45:44 +0200 Hello Brian, Your trannies and chokes work excellent! The big 30H choke works very Many thanks for your help in my successful project! Best Regards Bruno Dal From: "MAFRAND" <Dominique.Mafrand@wanadoo.fr> Hi Brian, From: Цветан ценков [mailto:digital1972@abv.bg] Hi Dear Brian P.S We attached photos on our dac inside Best regards R&T High-end audio design sistem team Bulgaria
|