"Enclosed are copies of all Traynor schematics I have. There are two circuits for the BassMaster, YBA-1, dating from 1966 and 1972 respectively.
Have fun. These amps have good transformers, but the rest of the components seem to be pretty basic. My bassMaster has the 1966 circuitry, and, except for a faint buzz, still works quite well. My 14 year old daughter uses it as a guitar amp, and it sounds fine."
Dr. Ian Ø Gallimore of Toronto
... many thanx to everyone for supplying schematics and text ...
-> ** Dr. Ian Ø Gallimore of Toronto, Ontario (email@example.com) - 66' Bassmaster YBA-1 / 66' Voice Master YVM-1 / 72' Bassmaster YBA-1 / 72' Custom Special YBA-3
orig. release date Oct 21 1966 - 2x7027A
I followed your recipe of mod's on my '69 YBA-1 and single channeled it by lifting a 100k resistor, changed the common cathode resistor to 1.5k and tried lowering the capacitance there from 100uFd but the amp wanted to regenerate at high gain settings, so I put back the 100u cap. I installed the 1meg A taper pot and changed the bright cap to a lower value so that the boost occurs at much higher frequency. This amp has 5k(5W) and 1k(15W) wirewound resistors in the p.s. filter section and I experimented with lowering the 5k to 2.5k but the amp didn't like it, so I un-did that mod. This version was also missing the additional filtering caps to the preamp, so I added(internally) a NOS 10uFd 450V cap to feed the 380V B+ to the preamp section. Finally, I tweaked the 100k feedback resistor by adding a 270k in parallel to give 72.9k to tighten up the output stage a little and I added a 3 prong AC cord. She's currently running a NOS matched pair of 1976 Amperex EL34's and my Marshall expert friend has said(unsolicited) to his friends that this mod'd BassMaster sounds better than any Marshall JTM-45 he's ever owned or heard. Thank You! for the inspiration to go inside. BTW, this amp really does do the going from 1 to 10 thing on the volume control, I may need to find a better audio taper 1meg pot but otherwise this thing is awesome!!
Dave Bender VP Engineering Ohmite Mfg'ing Co.
(i) ... in the YBA-1 bias circuit you can replace the load resistors by an equivalent "variable" circuit, it won't disturb existing voltages because the total load resistance is maintained (15k + 56k close to 25k + 47k) ... the same reasoning can be applied to any other Traynor amp with similar circuit ... I might use a pot that's 5k to 10k larger than the top load resistor ... then take the difference away from the bottom load resistor ...
(ii) ... the capacitor C14 of value 8uF cannot be changed too much unless the whole bias circuit is re-designed (10uF to 16uF is ok) ... a much larger value would produce a very slow charging bias circuit ... because the next leg of the bias circuit will likely contain a resistance that's somewhat close to 15k we can hike the next cap up a decade (80uF = 10 * 8uF) so that time constants jive in both RC circuits (by gross rule of thumb) ... either way, if you increase C14 expect your bias circuit to take a little longer to charge; in which case you might have to use the standby switch when powering up ...
(iii) ... for extra low "hum" in your tube amp make sure the filament wires are very tight against one another - you might have to unsolder one wire to give it an extra twist around the other in each link of the filament wire chain ... pull them against one another so they stand up high above the signal wires ... make sure grid wires run as orthogonally as possible in the viscinity of, and in relation to, the filament wire chain ...
-> ** Dean Hazelwanter (Dean.Hazelwanter@trinexus.com) - Additional Bassmaster YBA-1 schematics and Yorkville Sound update package
From: Dean Hazelwanter
I got very lucky last weekend, and found a Traynor YBA-1 head and YF-10 cabinet at a garage sale. It sounds great (and *loud*), everything is functional, and it even came with the original covers ... I've seen 2 schematics for this amp, but neither of them was exactly like the circuitry in mine, so I contacted Yorkville Sound's support department. Mike Holman (firstname.lastname@example.org) replied and sent the attached pdf file containing all the schematics he had ...
I took a look under the hood last night. It looks like it's a combination between 2 of the schematics. The power supply section looks *identical* to that shown in the schematic with a hand drawn, circled '3' at the upper right corner. I traced the preamp circuitry up to the output of the tone stack, and it's *identical* to the Oct. 21 1966 schematic marked 'original version'. I didn't get around to checking the phase inverter and output (Telefunken EL34) stage yet. I'll be installing 1R 1W resistors between the power tube's cathodes and ground this weekend, so I can check bias. I'll likely try a number of non-intrusive mods floating around, like separating the cathode circuits for the input gain stages, changing the volume pots to 1M etc. Essentially, move it closer to a 'plexi' configuration. I'll probably make a single 12" combo cabinet, and put the chassis from the YBA-1 in there. I can get an Eminence 12886 locally for $67. I contacted Eminence and it turns out this 12886 was custom-made for 'Yorkville Sound in Canada'
The Velvet Black dating information indicates my amp (#4052) was made in 1970, but Mike said it was made in 1969.
orig. release date Nov 09 1966 - 2x7027A - 4,8,16 Ohm output switch3
orig. release date Jun 22 1972 - 2x6CA7 - 8 Ohm output - B+@433v
orig. release date Jan 13 1967 - 4x6CA7 - B+@536v - *surge diodes - remove them !*
-> ** Eric Knudson (email@example.com) of Perth, Ontario - 69' Bassmaster MkII YBA-1A / 67' Signature YGA-1,1A / 72' YGL-3,3A Mk3 and the newest YBA-3A, YBA-3A71s, and YBA-3A73s->
released Jan 31 1969 - 2x6CA7 - 8 Ohm output - B+@525v
... the YBA1-mkII has slightly modified phase driver parameters compared to the earlier YBA-1 (stock Fender/Marshall values), the inclusion of input series resistance (R37 47k-Ohms) and lower grid bias resistors (R18, R19 both 47k-Ohms) are most likely aimed at curbing distortion at this preamp-output boundary , and this is where one usually finds a Master Volume control if any ... Pete Traynor's component choices are very good for curbing raspiness in the amp (specifically in this last triode stage where the most fuzz occurs typically) ... to me this seems appropriate for Bass players, but if you play guitar through a mkII you may want more life out of your amp : (i) replace the grid bias resistors by 470k-Ohm values to restore to normal gain levels - (ii) short out the input series resistance R37 with a short wire, so you can A/B it - sometimes I leave it in there; if you short R37 this allows for typical exponential grid-current loading which plays a considerable part in the overall clipping equation ... the amp should become a little more gutsy and gritty and, consequently a little less glassy ... lemme know if either or both tweaks work for you !
released Mar 02 1967 - 2x7027A - 8 Ohm output - B+@400v
released Jan 18 1972 - 4x6CA7 - 4 Ohm output - B+@431v - *surge diodes - remove them !*
I received a package of stuff from Yorkville today - two schematics and a instruction sheet. The instruction sheet is not very helpful - but it is interesting that Yorkville suggests using two 8 X 10" cabinets with the amp. Both scans of the schematics are at 300 dpi. The earlier one is very hard to read - I think the last revision date is 71. The later schematic is in a flip top case (the fan doesn't need to be attached through a connector) and a master volume - I am guessing the last revision date is 73. I suspect the amp I have is much earlier - 67 or 68.
released ?? - 4x6KG6A - 4, 2 Ohm output switch - B+@560v - *surge diodes - remove them !*
** Paul Markwalter
released Sep 11 1973 - 2x6BQ5 - 4x8" @ 8 Ohm - B+@398v
-> ** John Templeton
released Nov 28 1966 - 2x6BQ5
-> ** Greg Boboski of Winnipeg, Manitoba for the latest 70' YBA-2a/b ...
released Nov 19 1970 - 2x6BQ5 - 4x8" @ 8 Ohm - B+@395v
released Jan 13 1967 - 4x6CA7 - 8 Ohm output - B+@532v - *surge diodes - remove them !*
2nd released ?? - 2x6CA7 - B+@433v
2nd release Dec 12 1976 - 4x6CA7 - 4 Ohm output - B+@532v - *surge diodes removed ~!!*
-> ** David Register of Buffalo, NY for the different early versions of the YSR1 ...
released Jan 13 1967 - 2x6CA7 - 8 Ohm - B+@433v - w choke, reverb w tranny
released Jan 13 1967 - 2x6CA7 - 8 Ohm - B+@433v - wo choke, reverb w resistor drive
-> ** Gilles Grignon (Rainbow Music) from Cornwall Ontario for this big batch ...
released Jun 22 1972 - 2x6CA7 - 8 Ohm - B+@433v - wo choke
released Jun 22 1972 - 2x6CA7 - 8 Ohm - B+@433v - wo choke
released May 28 1973 - 2x6CA7 - 8 Ohm - B+@420v - wo choke
Rare YRM-1 schematic provided by Barry Beadman, Tom Pierce, and Chris Winsemius ... pic by Allen Modro ... posted 21/3/02 ...
... about the YRM-1 circuit : the front end is basically a single channel black-face reverb circuit, same reverb recovery mixing strategy with a 1Meg/100k ratio in the Traynor instead of the 3.3Meg/220k ratio of the '63 Fender Blackface reverb channel ... the output stage has a black-face phase-driver circuit driving a duet of EL34's ... the amp is plate coupled front to back - no cathode followers; so, very much a Blackface amp running on EL34's ... the reverb is capacitor coupled while the tremolo circuit is optical (thanks to Matt Jacobsmeier for the correction) ... one way Traynor amps tried to distinguish themselves from being straight Fender/Marshall hybrid-knockoffs was by choosing bass-bleeding tone stack cap values that sometimes made these amps a little "woofy" sounding ... you can experiment with the tighter and more natural sounding "Tweed" mid-scoop version by changing the 0.047uF and 0.1uF caps to 0.022uF in the tone stack ... and maybe even trying out a 56k tone stack resistor (instead of 100k) ...
** modded YSR-1 schematic provided by Alexy Galaxy ... posted 03/02 ...
** schematics provided by Michael Chubak ... posted 04/03 ...
** TS-140 schematic provided by Brett Day ... posted 04/03 ...
** Modded schematic provided by Dave ... posted 04/04 ...
** schematic provided by Chris ... posted 04/04 ...