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I built this transformer only valve amp back last year (March 2013). It has no capacitiors or resistors in the audio path but simply uses a Hammond Nickel core interstage transformer and a Edcor 5W OPT. Bias is provided by 4 X 9V batteries. The bias is permidiently on but the batteries virtually have no drain on them. The PS uses a step down tranni into a step down tranni backwards to generate about 200VAC. The amp runs on 180V and uses 2 X UX -171A RCA nichel plate 1920's tubes. The rec. tube is a 1940s "80" and the base is a 1940's plant box. The amp only produces 0.5W RMS into 8ohms but drives my Fostex FE206 based speakers (96 db efficient) to better than moderate volume levels. I do have to use a specially built tube preamp with a Pass B1 buffer to get the best from the amp. What I am looking for is any schematics of simple valve amps which only use trannies in the signal path. Can anyone post a link to (or a schematic of) this type of amp. Mine sounds excellent particularly with voice. I called the amp "Intermezzo" The scheamatic should show -40V (-36V in my case) negative bias for 180VHT.

On a whim purchased some vintage Krell monoblocks. They are US 110V, 50Hz and wondering if they may be internally adjustable to 240V via switchmode universal power supply or trivial change to the wiring on the primary transformer - anyone ever looked inside one of these? Couldn't find much detail on the power supply configuration for these on the web, although there are a few DIY projects for these models. Considering a refurb on these depending on the condition when I get them but I expect replacing power supplies will be quite expensive vs stepping down the voltage. If not internally adjustable without fully replacing the power supply, I will use a step down transformer but there would be a frequency mismatch which I have heard can be an issue for some electronics with linear power supply in terms of the power transformer running hotter and these already produce significant heat from what I have read. Also given the high current draw of these amps is quite high (manual indicates up to 20A for each) what transformer should I get to power both adequately? I normally use something like OnFilter http://www.onfilter.com/products.html?s=20ASF to clean up the power which I was planning on using after the step down transformer. Thoughts?

Hi Guys, I'm thinking of adding a tube output stage to my HQ Audio DAC which currently has Lundahl transformers there. I am really happy with the sound quality but I recently built a tube output stage for my DCX2496 and I'm falling in love with old records again. HQ DAC is super precise and detailed which makes perfect recordings sounds amazing but it is almost too revealing when I play some older stuff and I can't help assessing it all the time. I used to enjoy it but more and more often I just want to close my eyes and drift away. Tube stage I built has this vintage charm and is also more "forgiving". So I want to add it to the HQ DAC with some kind of switch. I have never done anything like that and I am not entirely sure what the best approach is. Ideally I would like to take the signal from the Clarity ESA caps which are already there and use the same RCA socket (my output is unbalanced). This DAC sends signal to both RCA and XLR at the same time but I can't see this being a problem. Any suggestions how to do it? Marek

I'm looking for ideas on effective methods to isolate transformers from the chassis of my DHT pre to lower vibration that affect these valves. Currently it has a total of 4 transformers/chokes that are bolted directly to the top chassis plate. To give you an idea of what I'm looking at the preamp has a square wooden skirt/frame that the aluminium top plate sits on top of. All parts are fixed to this top plate. The ideas could also be extended to further isolating the valve sockets which are currently decoupled with neoprene spacers. The valves are CX301A and are extremely sensitive to any vibration. Just clicking the stepped potentiometers causes feedback through the speakers. I'm not asking because there is a problem that needs fixing, more to improve things. Cheers!

Help!!!! One of my cherished early Quad mono blocks has a fried input/mains transformer, if anyone can point me in the direction of a working replacement or even a complete unit suitable for spares it would be much appreciated. Cheers.

Help!!!! One of my cherished early Quad mono blocks has a fried input/mains transformer, if anyone can point me in the direction of a working replacement or even a complete unit suitable for spares it would be much appreciated. Cheers.

Hi all Does anyone know of any current production ultra low capacitance isolation transformers, like this: http://www.ebay.com.au/itm/262611724584 Something with coupling capacitance < 0.005 pF like this Topaz. I've asked some of the major manufactures of iso transformers (even medical class) but while they have low leakage current, their coupling capacitance is 1000 pF or more. But maybe there's somebody out there making ultra low capacitance iso-trans that I haven't stumbled across on Google yet. Otherwise, if I purchased one from the US (one a bit cheaper than the above), does anyone know of a good electrician/technician in Melbourne could help me with fitting 1 x IEC connector and 1 x Aussie 3-pin plug socket, for local 240v to 240v operation. Cheers

A pair of James JS-6123HS output transformer for single ended valve amplifiers. Specifications: 90mA, 2.5K / 3.5K / 5K, 20W, 20Hz~60KHz-2dB, 3.2Kg each. Suited for 2A3 /300B/PX25 tubes. Has been removed from 2A3 working amplifier. Some small wear on the black paint.

Further information: AIRLINK Model BPS0508 Input: 230V Australian socket Output: 120V 2 USA sockets VA: 500 Bonus: USA to AU power cable Direct from manufacturer RRP 200 pounds, plus 100 pounds shipping to Australia, ad some 25% for import fees, tax and customs service fees 50 pounds – total 350 pounds equal to $635 AUD. Balanced power supply makes big sonic difference - more detailed and vibrant sound. AIRLINK Model BPS0508 Input: 230V Australian socket Output: 120V 2 USA sockets VA: 500 Bonus: USA to AU power cable Direct from manufacturer RRP 200 pounds, plus 100 pounds shipping to Australia, ad some 25% for import fees, tax and customs service fees 50 pounds – total 350 pounds equal to $635 AUD. o Model BPS0508 Input: 230V Australian socket Output: 120V 2 USA sockets VA: 500 Bonus: USA to AU power cable Direct from manufacturer RRP 200 pounds, plus 100 pounds shipping to Australia, ad some 25% for import fees, tax and customs service fees 50 pounds – total 350 pounds equal to $635 AUD. del BPS0508 Input: 230V Australian socket Output: 120V 2 USA sockets VA: 500 Bonus: USA to AU power cable Direct from manufacturer RRP 200 pounds, plus 100 pounds shipping to Australia, ad some 25% for import fees, tax and customs service fees 50 pounds – total 350 pounds equal to $635 AUD. s: USA to AU power cable Direct from manufacturer RRP 200 pounds, plus 100 pounds shipping to Australia, ad some 25% for import fees, tax and customs don't include photographs of the actual item being sold, your ad will not be approved

Further information: Input: 230V - Australian socket Output: 120V - Two USA sockets VA: 500 Made in the UK by world leader Airlink Transformers. Audiophile grade. Robust built and very quiet. Balanced power supply dramatically improves sound - makes it more detailed and "vibrant" like live music. I must admit that I had doubts about usefulness of balanced power supply till I auditioned it in my home few years ago. Now balanced power supply (another Airlink Transformers model) is permanently included in my audio system. Direct from UK manufacturer - RRP 200 pounds, plus 100 pounds shipping to Australia, ad some 25% for import fees, tax and customs service fees 50 pounds – total 350 pounds, equal to $635 AUD. Bonus: USA to AU power cable. Suitable for connection of two 120V audiophile grade tube or solid state devices - DAC, pre-amplifier, power amplifier (except of very high wattage models), CD player, Blu-ray player/streamer etc. Photos: PLEASE READ If you are advertising multiple items, you must post one bulk price only, or post seperate ads for each item If you include any reference to pricing whatsoever in this section (excluding RRP), your ad will not be approved If you don't include photographs of the actual item being sold, your ad will not be approved

Further information: Improves audio system sound substantially. Model BPS0508 Input: 230V Australian socket Output: 120V 2 USA sockets VA: 500 Bonus: USA to AU power cable Direct from manufacturer RRP 200 pounds, plus 100 pounds shipping to Australia, ad some 25% for import fees, tax and customs service fees 50 pounds – total 350 pounds equal to $635 AUD. Direct from manufacturer RRP 200 pounds, plus 100 pounds shipping to Australia, ad some 25% for import fees, tax and customs service fees 50 pounds – total 350 pounds equal to $635 AUD. Photos: PLEASE READ If you are advertising multiple items, you must post one bulk price only, or post seperate ads for each item If you include any reference to pricing whatsoever in this section (excluding RRP), your ad will not be approved If you don't include photographs of the actual item being sold, your ad will not be approved

Item: Tortech Isolation step down transformer, 100vLocation: MelbournePrice: $ 75 plus paypal and shippingItem Condition: Used in good condition. No box.Reason for selling: surplusPayment Method: Pickup - Cash, Paypal, bank transfer Tortech Step down transformer to 100v. Bought new from Tortech only used for 1/2 hour because didn't suit my gear. Suit Japanese equipment like preamp or CD players etc.