Yamamoto Sound Craft
YS-605P 38cm flat baffle speaker 1 unit

The YS-605P is a speaker system made by refining ALTEC's 605A or 605B coaxial speaker unit by Yamamoto Acoustic Crafts and mounting it on a simple flat baffle. ALTEC's coaxial unit, which has a high efficiency of about 100 dB/1 W and 1 W.1 m, and can obtain a lively sound for a small-output tube amplifier, has been remodeled as an original specification unit that has improved sound quality by pouring in Yamamoto Acoustic Craft's many years of technology.

No box, simple flat baffle method

The unit uses a planar baffle system for the 605A and B, which have little midrange elevation and relatively low frequency levels can be easily obtained. The flat baffle provides a natural and clear sound that cannot be obtained with an enclosure. The volume of the bass range is modest, but the clarity of the mid and low frequencies is an advantage that is hard to obtain.
The baffle is made of laminated wood from Asada Sakura, which has the best sound as a material for speakers, and has succeeded in commercializing it at a low price.

Adoption of round horn machined from ebony wood

The main feature of the YS-605P is the use of a round horn machined from original ebony wood. It is a horn unit with almost no resonance due to the hard and dense solid ebony wood. The shape of the horn is a round short type with minimal impact on the woofer unit, and a horn with a high cutoff frequency.

Simple network with one capacitor

ALTEC summarizes the frequency response by constructing a network that suppresses the mid-range part. Yamamoto Acoustic Crafts designed an original horn unit with the aim of adopting a network that can serve as both a filter and an attenuator with a single capacitor by taking advantage of this high-frequency attenuation characteristic. A very simple network with a single capacitor provides a practical frequency response, and the discontinuity of the phase characteristics between the bass and treble is minimized.

The condenser for the filter uses a high-performance lug terminal type polypropylene capacitor from Dearborn, a U.S.-based sprag terminal type impregnated with a high-strength epoxy resin in an ebony case. The speaker terminals have been replaced with Yamamoto Acoustics' original large terminals, which reduces the number of contacts in the terminal part by a total of four, and greatly increases the amount of information in the music.

In the past, it was said that the ALTEC604,605 series speakers were suitable for jazz and popular music, but not for classical music, but it is also a major feature that these improvements have increased their suitability for classical music.

Model	Planar baffle type 38cm coaxial 2-way speaker system
Speaker unit	ALTEC 605A or 605B (modified by Yamamoto Acoustic Crafts)
Mid and high sound unit quality	Machined ebony material, circular horn
Flat baffle material	Asada Sakura laminated wood 25mm thick, urethane coating
impedance	16Ω
Frequency response	35Hz~18,000Hz
External dimensions	996(W)x910(H)x285(D)mm
weight	36kg

*YS-605P uses a vintage unit. These units were manufactured about 40 years ago, and their condition varies from unit to unit. There are some differences in condition, appearance, and sound quality, such as those that can leave the old diaphragm as it is, and those that have been replaced by replacing the diaphragm. Please note that there may be differences between them at the time of delivery of the product.