• RCA input from the side to give the shortest signal path and keep noise to a minimum.
• OPT generously sized, wound with special audio coating, and made from cores from Japan. The new OPT is larger. Usually a larger core gives better dynamics and bass/transient response at the expence of high frequencies. However this new transformer is wound by a specially programmed CNC machine which puts down each layer with no scatter (perfect lay). Result is a transformer with much tighter, compact windings and less capacitance which benefits the high frequencies. The larger core then allowed is better at resisting saturation which occurs in the bass frequencies first. The new OPT are a major step up. Extra taps to adjust within range of 2K to 8K
• Rectifier tube (unheard of at the price) in the power supply lets through all the magical tone of Direct Heated Triodes such as the 300B etc and is cheaper to roll than the 300B but just as important. It also saves the power tube as solid state rectifiers without soft turn on will scorch the power tube with a tremendous surge of current at switch on.
• Choke filtered power supply. A must or be forever mid-fi
• Quiet EI power transformer with secondary taps: 0-2.5-7.5v for power tube filament (allows use of Tentlabs filament supply); driver tube filament: 0-6.3-10v; rectifier filament: 0-5v; HT: 400-300-0-300-400v and 2 x 25v buck/boost
• Solid 1cm thick aluminum face-plate, matching side panels, milled solid aluminum chassis top, solid aluminum covers
• Quality parts throughout and point to point wiring.
• Includes instruction manual, all tubes (ordered separately), hookup wire and parts.
• Easy to put together with a spacious working area in the chassis.

The output transformer quality is always of paramount concern especially with 300B amps. The LD Signature uses selected Japanese EI core material. The manufacturer winds the primary and secondary coils with a special technique to achieve close coupling and perfect lay. Traditional paper and varnish is used for coil insulation and traditional damp proofing techniques are also applied. The transformers are visually impressive but even more impressive is their ability to a deliver smooth solid and musical deep-bass.

The main hardware comes pre assembled. The transformer primary and secondary connections are already done. Point-to-point wiring is used and is very easy to assemble with clear, generously illustrated, step-by-step instructions. The power transformer can run from 110/120/220/230 and 240V.

Recommended LD Signature Upgrades

These mods options listed below can be done in stages. They increase dynamics and liquidity of the unit. The list is growing and is the result of successful mods made by many. However, just to stress that the LD Signature does sound very good in standard build and these are upgrades to push the unit to the next level.

Recently discovered major upgrade is using the 6SL7 parallel with CCS loading on the anode. This gives major headroom for driving the 300B, about the same gain as with SRPP, much less distortion on dynamic peaks and sounds wonderful. Much more pace and drive, tighter bass, greater separation and more expansive soundstage.

Next:

1. Easiest and biggest result: grid choke. Then not far behind...

2. Obligatto 12uf B+ to cathode resistor and 47uf film cap across cathode resistor for the full WE connection. Less noise and greater transparency.

3. After that is the MU mod with the teflon tinfoil coupling capacitor.

The three choices above each make a significant change to the nature of the sound. Next, to a slightly lesser degree and to be considered more like seasoning.

4. Kiwame Resistors. These impart a more vintage sound. Or tantalums - sweet tone with more detail.

5. Silver wire pak.

NEW! The famous 91 circuit now available:

Based on the original 300B theatre amp and the first hi-fidelity experience for many, this circuit uses the WE310A pentode driver and 274b rectifier. Input sensitivity is about 6db more than 6SL7 SRPP driver. Maybe this is the 'right' way to listen to a 300b - very powerful and tonally rich midband dynamics. Although the 91 has a reputation for being 'dark' sounding, the LD91 circuit implementation and choice of Blackgate, tantalum, silver wire/caps for parts has overcome this and achieves 20-20k <-1db; 12-45k -3db. Of the possible drivers,this may be the best. The circuit is a little more complicated than SRPP or MU so allow extra time but it well worth it.