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1969 Traynor Bass Master YBA-1 tube amp marshall PLEXI killer - $800 (Santa Barbara)
condition:
good
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1969 Traynor Bass Master YBA-1 tube amp 40w, well known to be based on the Marshall plexi and overbuilt and very reliable. This one has 6L6s in it, not sure if it was modded for it or not, but what a sound.
Has 4 digit serial that indicates it's from 1969, though it's missing the "drip edge" trim.
Weighed 30 lbs for me, but my scale could be off.
Size: 19x9x11
This thing sounds INSANELY good, somewhere between a classic plexi and AC30 to my ears. I had a stock '77 Marshall JMP 50 watt master volume 2204 and this sounded WAY better to me.
$800. PRICE IS PRETTY FIRM. I don't really want to sell it, so holding out for asking price. Most offers for less will be ignored. Trades possible if you have something I want and it's a great deal for me. You may be able to find one cheaper online, but I doubt better sounding or be able to try it out.
CASH ONLY IN PERSON. No bullshit.
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This amp has the perfect plexi sound with a bit more bite like an AC30. It is my sound second to my other amp that has slightly different sounds along with spring reverb, a Valvetech 22.
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"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. 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.
Dimensions: 19"x10"x13"; weight: 39 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. They feature a 'flip-top' design that allowes the top of the head to open like a lid. Bass-Masters are identical in appearance to the Voice Master/Signature;
Middle versions: Solid-state rectifiers started showing up in approximately mid 1966. 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. 437 volts); this may have gotten higher after 1971, but into the summer of 1971 I'd expect the plate voltages on 6CA7s to be down substantially from the YBA-1A; have the chassis sliding-in ala Fender.
Last versions have that easily identified rubber and 'chrome' molding running around each end of the head cabinet; mine is from 1971 and is this last version; 1972+ models have no choke; [a 1978 is] black with the black plastic fabric and [has] the baby bumper trim, [it has] two 6CA7 and three 12AX7A tubes in it [and] no fuse holder, just a red reset button
I put Mullard EL34s in my YBA-1. [...] When [the YBA-1] ran on 7027s, it was a rock machine (think Black Crows, Zep, etc.). It probably has a bit less bottom end and more mids and highs now.
I have swapped out the 4M volume pots for 1M, and put a 47K resistor in the NFB loop. These mods are worth doing to any Signature/Bass-Master, IMO."