Black Beauties ... D3a Phono Stages

 Hi!

Two all black phono stages got finished recently.

This one is using all silver transformers and comes in the portrait chassis style:

This particular unit will join the 'Black Beasts', a system which was still lacking a proper phono stage.

The other is a partial silver D3a phono in the landscape chassis style.

Although I am introducing all new chassis for the entire lineup these traditional chassis styles will continue to be offered as an option.

Best regards

Thomas

Upcoming amps, preamps and DACs with Compactron tubes

Hi!

A whole bunch of new stuff is in the making in my Compactron line of electronics.

After the introduction of the Compactron Preamplifier and getting orders for a Compactron line stage and Compactron phono stage I decided to launch a full line of electronics with Compactron tubes. The following gear is planned to be finished until end of January 2024:

1. Digital to Analog Converter with Volume Control

This DAC is based on the same concept as my previous DACs just with different output tubes and a more compact approach with simplified power supply so that everything fits into a single chassis. The output will be volume controllable using transformer volume control. This is for people who use digital sources only. It can accept data from a laptop/PC or music server via USB or from a transport via Coax. It can drive a power amp directly through long cables.

2. Preamplifier

A simpler version of the first Compactron Preamplifier. It has a phono section for MC cartridges, a balanced input and two SE inputs. A full function preamplifier but with minimal features, just volume control and source select. Volume control done with transformers. It will have both RCA and XLR outputs and low output impedance.

3. Stereo Power amplifier

A single ended power amp with 5W per channel, two stage design, interstage transformer coupled. Like all Compactron electronics in a single chassis.

4. Digital to Analog Converter

The same as the one above but without volume control. Meant to be used with a preamp. Transformer coupled output. Balanced and single ended outputs.

5. Phono Preamplifier

A entry level phono preamplifier for MC cartridges. Meant to be used with an active preamp.

6. Integrated Amplifier.

Single chassis integrated stereo amp based on the same circuit as the power amp above. 5W per channel.

7+8. Mono power amplifiers.

A pair of mono blocks based on the same principle as the stereo amp above but with 10W per channel.

9. Digital to Analog Converter

A simplifier version of the DAC listed as nr. 4. RC coupled outputs, RCA out only.

10. Line Preamplifier

Line preamplifier similar to the one which I built already. Just without phase switch but 2 balanced inputs and 2 SE inputs.

I plan to demo all these at the Munich High End 2024. Yes I plan to be there again. Each of these units can be customised with different features. Chassis will be made in different colors to showcase the possibilities. Stay tuned for updates as assemblies of these units starts.

Best regards

Thomas

Tube of the Month : The 6AY11

Hi!

This is the last of a miniseries of 4 consecutive posts about Compactron tubes. This months choice is the 6AY11.

The 6AY11 contains two triodes and two diodes in one bottle. Similar to the 6AG11 which was presented in July. But it has different specs.

The 6AY11 and the 6AG11 share the same pinout but the triodes in the 6AY11 have an even higher amplification factor of 100. This comes with a plate resistance of a bit over 50kOhm. Quite interesting if you are in need of a triode with very high gain and if you do not want to resort to the 12AX7. Both triode systems in the 6AY11 have the same parameters. See the General Electric data sheet for a complete set of technical details. There are so many gems hidden among the Compactron tubes which deserve more attention. This is probably one of them. Time to leave beaten paths and explore some alternatives. As always here the curves from the data sheet:

And curves from a tube sample:

I do not have many 6AY11 in stock, all of mine are Westinghouse branded but probably made by GE.

The tube from different angles:

Some close ups and more angles:

Since I do not have many of these I don't want to open one. The internal construction is anyways similar to that of the 6AG11 which I have shown in detail. But I would like to close this post by entertaining you with pictures of the 6AY11 in operation.

I hope you enjoyed this presentation of yet another Compactron beauty.

Best regards

Thomas

The Compactron Phono Preamplifier - part 2

 Hi!

The variable EQ Compactron Phono Stage is finished.

Some photos of the initial construction steps were shown in part 1. Here the finished unit.

Besides adjustability of input impedance and input capacitance, there are selector switches for different bass turn over frequencies and different amounts of treble roll off to adapt to the recording curves of vintage records labels.

In addition the absolute phase of the output can be switched.

The phono stage is meant to be used with MM cartridges or MC with external step up transformer. However in its highest gain setting it is useable with MC cartridges directly in if they are not loo low in output. That is how I am testing it right now.

Gain is selectable in 4 steps via a switch on the back side. More details about this in the post about the Compactron Preamplifier. The outputs are available as RCA as well as XLR sockets. The outputs are transformer coupled and have very low output impedance.

Knobs can be chosen to taste.

More colors available soon.

My favourite is the all orange front.

Here a pic of the inside. Some of the wiring still not final in this photo as it just was an initial test run.

All power supplies including the DC heater supply are choke filtered.

Vents directly above and below the tubes.

The feet are stainless steel as well as their counterparts on which they are supposed to sit to avoid damaging the surface below.

Other feet are available on request.

Stay tuned for more new developments in the Compactron series. An entire line of electronics is planned with Compactron tubes and in this chassis style, including DACs and power amps as well as an integrated.

Best regards

Thomas