One [channel] sounds kind of like a "bright" channel and one sounds regular Two 6CA7/EL34 power tubes, three or four 12ax7s, solid state rectifier; hand wired, very high quality work, simple easy-to-modify circuit; larger [than the ones used in the Bass-Master YBA-1] 50-watt Hammond transformer (7 lbs.); Often operated with 4 ohm loads; best used with an eight ohms cab Runs on 540 volts, weights 54 pounds - bigger transformers [than the YBA-1] Dimensions: 8"x18"x10" (HWD); weight: 40 lbs.? (source: Catalog) Early [Bass-Master] Mark IIs have the (noisy) fan mounted on the end [in the cabinet side], later [Bass-Master] Mark IIs (with lift-off top, and the reflector 'Traynor' logo) have it mounted in the back [center]; Silvery grey grille cloth; Can exceed 600 volts on plate; expect about 550 volts, if you're lucky (one has eported 537 volts on plate) Early models are identical in appearance to the Voice Master/Signature.I have swapped out the 4M volume pots for 1M, and put a 47K resistor in the NFB loop.A 1967 YBA-1 is reported to feature a diode rectifier.The used tubes are, as indicated in the amp: Two 6CA7s (replaceable by EL34s) and three 12AX7As (also called 7025s or ECC83s); plate voltages have always been a question on these units, but I think this may be largely because of confusion with the YBA-1A models that run VERY high plate voltages; most of the YBA-1 models probably come in somewhere /-450 volts (one has reported 425 volts on plate, another one ca.A YBA-1 has a nominal 8 ohm output, and the two speaker jacks are wired in parallel.Runs on less than 440 volts, weighs 39 pounds Dimensions: 8"x18"x10" (HWD); weight: 40 lbs. (source: Catalog) Silvery grey grille cloth; Original layout was very close to the tweed Bassman and the Marshall JTM-45 50-watt models; noticably huge big heavy transformers are a Traynor hallmark in these units up till the approximately 1972 models; Early models were tube rectified (5AR4) and used two 7027A power tubes.typically playing a new gibson les paul "faded" through them. Even after a friend helped me switch the power supply to todays standards and no buzz and shocks occured. I am told it may need some work on the tubes (cost about same as amp itself). 1971 YBA-1A Bass-Master Mark II (top not removable despite later style case), front view, angle 1971 YBA-1A Bass-Master Mark II (top not removable despite later style case), front view 1971 YBA-1A Bass-Master Mark II (top not removable despite later style case), back view YBA-1A Bass-Master Mark II, catalog page YBA-1A Bass-Master Mark II, schematic 1/1969-12/1970 YBA-1A Bass-Master Mark II, schematic 1/1969-12/1970 YBA-1A Bass-Master Mark II, catalog pages, manual, fan conversion, schematic 1/1966, schematic 1/1969-1/1972, schematic 1972-2/1973 YBA-1A Bass-Master Mark II: Looks to be the same as the other one with a choke except it shows 6CA7 as the power tube instead of 7027 (Larry).
Sound - Reliability - Price CAD 5 [used], condition unknown, Scarborough, Ontario, Canada, February 7, 2001 Very hard to find. Dyna-Bass, front view, angle (apparently the same as the following) 1963 Dyna-Bass, serial number 0011, front view, angle Features Two channels, deep (bass), and bright (guitar); each has an attenuated and a normal gain input (like the old Marshalls); no reverb Volume control channel one, channel two; treble, bass, low range expander, high range expander (passive); the low range expander may sound like a mid-range, the hi range expander may sound like presence (on Marshalls or Fenders) to some (the section is a virtual clone of that of the Marshall JTM-45); standby switch; pilot light; ground and on/off switch; no fan One main speaker output, impedance is not indicated (runs fine using a cab of eight ohms, also often operated with four ohm loads), one "extension" speaker output also without indicated impedance.
[Oct 2002] US 0 used; one can be bought for under [US] 0 - a total bargain US 0 [used], needed a little work but playable, cheap buy US 9 used, you can get one cheaper CAD 0 [used], good condition, seen at Songbird Music, Ottawa, November 1998 (since January 1999 though, it had changed its condition to 'very good') Rating very good amp My personal opinion is that the YBA-1 is better for guitar, while the YBA-1A is preferable for bass.
My YBA-1A [...] uses 6550s and it's the best rock bass head that I've owned.
The YRM-1 is good sounding, but not as responsive, raw, or soulful as my YBA-1. presently using the yba-1 through an old sound city 4x10 which i respeakered with 80 watters. breaks up like a champ when driven and sings sweetly when i turn down the pickup volume(s). It's a beautiful computer-drawn schematic, but an error was made in transcribing the previous schematic.
My personal opinion is that the YBA-1 is better for guitar, while the YBA-1A is preferable for bass. [...] typically playing a new gibson les paul "faded" through them. I got it brand new back in the late 1960s (I traded a dealer my Fender Super reverb even for it). It can be heard on all my recordings, and you can [see] me using it in the videos of my band, Terrain. Specifically, R36 needs to be 68K, not 6K8 as written.