My Mk3 is biased at 26 mA. I was also surprised of the low value. Checked out the curve form on a scope and apparently 26 mA should be enough. Of course I do not solely trust my eyes in these matters so I tried biase currents up to 50 mA. At the same time experimenting with the negative feedback. However, I did not experience any remarkable positive changes. The sound was still cold and .... err ... 'edgy'.
When you say that your sound is improved by setting biase at 40 mA. Does that refere to the clean sound or the distorted sound. Or both?
Actually the most radical change in the sound of my Mk3 came when I changed the mullard PI to a chinese tube! Do I just have a bad taste in sound, or what?
/Olof Westman
Sir;
As per your request at the bottom of your Traynor schematics page, I am notifying you of two corrupted and one 'not found' GIFs. Both GuitarMate Reverb schematics are incomplete. The scans are truncated at the bottom. Trying to view the '69 BassMaster Mk II schematic results in 'The requested URL /~jc/69_YBA1A_BsMstrMkII.gif was not found on this server.'.
I am a previous owner of a Garnet amp, but I'll be damned if I can remember the model. It's been too long! I recall square neon indicator lights, and it seems to me it had large black pointer knobs, some of which pulled out. I remember it didn't come with a footswitch for the distortion, so I made one out of an old shit-brown Maestro fuzztone pedal which had either died or I had gotten tired of. I don't remember it being called the 'stinger' effect, but again I could have just forgotten. I also don't remember it having a tremolo circuit, but the preamp schematics you have show tremolo on all of them, so I probably didn't use it.
Anyway, thanks to your site I got to reminisce a little about a piece of equipment I had almost totally forgotten about. I also gained a new respect for it, as I was a typical young guitar player of the day who thought the sun set on Fender and that I was only using second rate equipment. Makes me wish I had kept it (I also can't remember what happened to it). I was also surprised when I took a look at the schematics to see EL34s in the power section. I guess I never had the amp long enough to change the power tubes, because all these years I assumed it used 6L6s.
Thanx for the warm fuzzy memories!
I was talking about the clean sound althought it does sound way too bright if you use a Tele and turn on the bright switch. If I want distortion I tend to use a pedal . I wonder if Traynor used different types of speakers throughout the Mark3 's production life? That may also account for the difference in sound. As far as the chinese tube for the mullard, the best tube is the one that gives you the sound you want.
>The very early models originally had 7027s, but most (including mine) were long ago converted to 6CA7/EL34s - Yorkville supplied instructions for conversion. 7027s were expensive and rare even in the early 70s. All the later case style models came with EL34s. Mine is a three digit serial number (253) from the mid sixties and has a 5AR4 tube rectifier. Your model would date from 1970
>I am not sure which tubes your amp came with originally - it was built close to the date of the switch of tube types and case styles.
>It might be worth wiring the output tubes like Marshall rather than the unusual Traynor EL34 circuit - which is clean and reliable, but not to everyones taste. Perhaps JC will have a comment on this.
... interstingly, the Traynor circuit is nearly identical to a classic 50w Marshall, the only difference is that the phase driver is slightly hotter in the Traynor line ... there are a few things that Pete Traynor did in order to avoid copying Fender and Marshall outright ... one of these changes is the replacing of the 10k resistor by a 6.8k value in the already-hot FenderTweed/Marshall phase driver circuit ...
Both in Marshall 50w and Traynor Bassmasters the feedback mixing circuit is the same (100k/4.7k with presence) ... the 470 screen resistors get changed to 1k/5W resistors in the EL34 conversion and 5.6k grid resistors are installed on the sockets ... these amps really sound nice on 7027As and also good with EL34s ... depends on how fussy you are I guess ... the tone is personal, both types of tubes have really nice breakup; because the tranny/load isn't balanced like in a Marshall the Bassmaster doesn't sound like a Marshall even when running on EL34s (unlike Garnet amps which are very Plexi-like in power tube tone) ... I'd stick a few more uFarads in that power supply at least (Traynors are known to be very weak in this area) ... btw, these amps are awesome !! ...
jc
>ANYHOW >I know that each amp needs to be "re-biased" when replacing tubes. What does this entail? What does it mean?
In guitar amps that have very good output trannys some players are fanatic about bias, they buy pairs of matched tubes that have near-identical specs and choose the two closest and keep the other as backup in their duet amp while in a quad amp they buy the same matched quad and then have idle currents added so that they balance equally side-to-side (zero difference) ... the reason for all this fussing is that balance in the output stage exhibits a strong dependency to bias conditions if the power tube are not statically and dynamically matched enough side-to-side ... for your amp as for the best guitar amps, I'd recommend you get yourself some tubes from a reputable dealer (I think New Sensor in NY hasn't screwed anyone to date and I've had good service with them) spend a few extra bucks and consider NOS maybe, but at least burnt-in and matched is important ... you MAY want to verify matching yourself in-circuit using the tranny shunt method if you really feel like getting into it ...
Be warned though, the 540volt B+ of the BassMaster MkII is nothing to kid around with ... the tranny shunt method involves manipulating a live B+ circuit with a short across both hands ... in theory this method is safe except in practice it can lead to dangerous accidents ... if you do it then you gotta do like the guys in ZZ Top do and tuck your beard, hear and Harley chains INSIDE your Harley t-shirt; wear rubber gloves if you are prone to shaking and don't do it at all if you are not completely sure on what to do and how the technique works- I'm not kidding this is stuff you don't let kids do alone at home for the first time ...
BIASING CLASS_AB TUBE AMPS
biasing is a crucial aspect of most guitar amp operation and performance (cause most are class-AB) ... this has been typically neglected in the past by us all until one day someone asked why there was some much variation between different versions of the same tube amps ... tubes and their dynamic and static properties play an intimate role alongside the output tranny (most important of all parts in the amp electronics) and speakers in setting the operating characteristics there ...
In his Vintage Guitar articles Ken Fischer did mention some useful Marshall amplifier biasing techniques ... on one occasion I asked Ken about this ... in a nutshell he confirmed the existence a point just beyond the notch-threshold level, some kind of 'sweet spot', some kind of electronics sasqwatch, lurking beyond the notch-less monster ... of course, you can always bias your amp hot if you want or cold ... for example, Fender 6L6 amps loose their smoothness if they are biased too hot ... you're also playing with the plate impedance/reflected tranny load ratio when doing this ... this may explain why Gar Gillies is dead set against having variable bias installed in his amp, since he's set the bias at the point where his amp's 'ratio' sounds best, he's possibly worried that might get lost in the hands of an inexperienced tech, I can't blame him in a way ...
in theory a class-AB power stage will imitate a good class-A push-pull circuit (i.e. be notcheless and symmetric) when the turn on and turn-off characteristics of the tubes match side-to-side and the OT is well balanced) ... in theory the point where the notch dissapears in a sinewave-oscilloscope test is supposed to give maximum power efficiency and this is where Marshall used to instruct certified Marshall tech people to bias their amps ...
INCORPORATING VARIABLE BIAS
In true Tweed fashion the '66 and '69 BassMaster amps have fixed bias circuits ... to convert to variable bias the fixed resistor (R30=56k in the '66 version and R21=47k in the '69 version) need to be changed to a 33k resistor (to ground) in series with a 22k or 25k pot with sweeper biasing the grid circuit (I like to add extra filtering here to lower hum in class-AB amps) ... set sweeper to most negative voltage before turning amp on again ... I do it on the fly over the old part (use a trimPot), make sure solder connections are short and solid and the new parts won't move even if the amp is knock hard ...
FINE-BIASING BY EAR
this is the best technique, even if you measure bias scientifically with a meter you're still giving the final ok with your ears ... after you've installed a variable bias circuit in your YBA-II, you wanna start with the bias set real low (most negative DC voltage at grids) and then you pick up your guitar and experience the mushy sound of an under biased amp ... turn on the amp and, without playing at first, notice how long it takes for the amp's white noise to stabilize (there's a high impedance bias feed in these amps as in 50w Marshall amps and the Fender 6G11-A Vibrolux) ...
now slowly raise the bias and again play your guitar (wait or the circuit to stabilize to the new level) ... also, be extra careful when going back and forth if you're keeping your guitar in your lap (like make sure one hand isn't touching or gripping guitar strings when handling components with the other hand in a live amp- this is potentially lethal SO PLEASE BE CAREFUL AND TAKE YOUR TIME!! :) ... as you increase the bias you'll experience different regions of tone and dynamics ... the zones can be listed as follows:
(i) the under-biased zone - amp is weak and fuzzy/distorted
(ii) the transition zone - amp looses it's fuzziness and ranges from cold/warm
(iii) the hot zone - amp looses its warmth and becomes harsher
(iV) the red zone - metal base turns red inside glass (ease back on bias !!)
in my experience the 'sweet spot' seems to lie somewhere around the top end of zone (ii) but this I would expect to vary depending on amp, tubes and player's feel ... tubes that have symmetrical turn-off characteristics will exhibit true notch-less behavior when well-biased and the output stage will be at its janglyest ...
TRANNY SHUNT TECHNIQUE varying the bias means varying the idling voltage of the grid circuits, more negative grid bias voltage means lower idling curent through the power tubes (equally) while less negative grid bias voltage means higher idling curent through the power tubes ... there's often confusion here because some people refer to grid voltage when they speak of bias while others refer to curent; the engineering field refers to the current version which makes more sense- more strongly biased means higher plate current and more gain ...
the best way and the most dangerous way to measure turn-off caharacteristics and static matching is to perform tranny shunting of the OT legs in order to measure as closely as possible in-circuit idling currents ... other methods are more laborious, safer and less accurate ... installing cathode resistance does not provide accurate enough translation (though much safer), while socket meters don't necessary track over current rangers and temperature as well, pricey too ...
-> with the amp running and idling in duet mode (no signal, two power tubes at a time- one per side) you short the B+-to-plate OT tranny legs one at a time with a multi-meter set in mA mode and read the current ... once one probe has landed, make sure the other probe never touches you or any metal in the amp except for the right one- there are only two places to land, make sure you know exactly where they are and whether or not you can clear them without touching any adjacent parts ... typicaly, I land on the B+ which is somewhere on the board next to the filter caps and then go to the power tube pins that are wired to the OT one at a time ... when shorting out an OT leg it is normal to experience zero output noise across the speaker ... the tricky part is having probe tips stay where they are as you lift your head and read the meter ... wait a little bit for meter meter to stabilize and then lift probes slowly together ...
... because you're carrying a short in your hands and applying the short to the highest source of tension in the amp you don't want to accidentally touch the chassis (or strings or anything grounded) with one hand while the other might be touching the B+ ... make sure your meter has a proper fuse in it or expect to experience unpleasant displays of rapid energy discharge circulating in your very viscinity ... for quartet amps I test two tubes at a time ... if you've bought tubes that where properly burnt in and then matched then idling currents should lie within 5%-10% of one another when in the right bias zone ... there's no point having someone tell you what bias level is write for you, like you said this is something you should set for yourself ...
I hope this helps, feel free to ask if anything seems unclear ... if I've made a typo or something appears to direct information in an unsafe manner let me know ...
jc
My personal opinion is that the YBA-1 is better for guitar, while the YBA-1A is preferable for bass.
Hey I read your thing on the traynor email list very clear info about biasing.
I just had on question. I have read that an amp with less current flowing from Cathode to plate is "over biased" and and amp with more flowing is "underbiased" opposite to what you wrote but I guess that might depend on perspective eh? Anyway, I`m not tying to be cheeky! I just wondered. Great article.
(... actually it is the other way for me, since bias refers to "setting idling current" in the mind of most engineers and designers (and the literature) then high bias means lots of current flowing through the tube ...)
That was very informative. Thank you for taking the time out to explain that. Now, I do realize that this really IS a fine-tuned art itself. I wish you were in the NWest, I'd be coming to you to tune mine up. I do have a YBA-1, and perhaps the process to replace tubes in this particular model is not as encompassing? I will take it to a tech. THANKS M
Hey JC,
THANKS !!!!
best regards - Tom B.
>no prob ... I think it's more useful overall to associate bias with gain and heat dissipation - and so this is the accepted view in general - i.e. high bias means greater current through tube, greater small-signal gain , ... also greater amounts of dissipated heat as a direct product ...
Sounds like I ought to drive to BC and have you bias my YSR-1! This one goes in my "Tech" folder. Thanks.
PS-Did you ever get those schematics I sent?
Thanks very much, it is defintely cool, and I appreciate it. I've already heard from Brian and written him back. The timing is a little bad because I just this morning bought an old signature model with a tube rectifier. i figured I might use the tremolo tube to hot-rod it a bit. I'll have to see how much Brian wants for his, I wasn't sure if he was talking $350 US or Canadian. If it's $350 US, it might be a bit of a stretch. I'm still at work, so got to run.
thanks very much - Tom
well, my buddy Brian Hedberg is selling his ealry Bassmaster (I think its a 67) since he's buying an old VOX AC30 ... anyway, I've heard and played his YBA1 and it is one of the best sounding Traynor Bassmasters in my opinion ... I told him you were looking for a real one like his, so he asked me for your email and you should be hearing from him soon ...
I'm assuming this is coOoL for you, if not I apologize ... :) jc
>Hey JC,
>Thanks very much for all of the info. I'm scrounging around and finding a number of these amps, but having a tough time finding the right one. I've found some later YBA-1's and a YBA-1A, but I'm going to hang in there and look for an early model. Sure would appreciate a shout if you run into one! If i find it, i may very well get a 4 x 10 to go with it, just like your friend. Sounds like it would make a killer rig to haul around! Thanks very much for taking the time to reply.
>have a good one - Tom B.
It seems to be voiced along the lines of my Custom Reverb, very clean sounding without the Fender scooped midrange. This model has a sealed back with 12" speaker. I pulled all 20 screws to find a speaker, which I believe has an Alnico magnet, dated 12/22/70 and label "designed for Traynor by Marsland Engineering Limited." Anyone ever heard of them? It sounds pretty good and the amp has a very strong high end.
I plan to keep the 2xEL84 power section and convert the preamp to the Kevin O'Connor design from Tonnes of Tone. I don't currently own a high gain amp and am looking forward being able to dial in some tube distortion.
If anyone has a tidbits about this amp, I would love to hear them.
Lee
Please take my e-mail off of your website.Ê I do not want my e-mail address getting around.
Thanks,
Regards,
>I own a Traynor TS-50B. Any info available on it? I need to repair it. I put my girlfriend's keyboard into it and blew it. Evidently, the amplitude of the keyboard's output is too high. Any ideas? Also, add me to the mailing list.
>Thanks,
>Larry Nagode
I truly appreciate this board! Yes...does anyone know of one similar to this to get information on Sunn Amplifiers? I found an old Sunn 200 Watt 4 channel PA with reverb, in the free pile! It works! Help appreciated. Sorry to stray from the Traynor subject!!! (apologies) Mary
Hi. Just thought that I'd send along a picture of my Traynors. The bottom 4x10 is a traynor cabinet which I rebuilt and recovered Rick
The list isn't automated (I couldn't get the automated stuff to work on the email system here, as it has various non-standard features, although I may try again at some point), and so does not detect binaries and stop them.
If you wish people to see a picture of your amp the best idea is to send the picture to me at aaron@cs.york.ac.uk and I can put it on the web, and then let people know that it is available.
Songbird Ottawa has some interesting Traynors for sale at: http://www.songbirdmusic.com/ottawa/guitar/amplifie.htm
>Traynor YGA-1 Signature 50 watt tube head with trem. - very good 260.00 Traynor YBA-3 Custom Special 100 watts tube bass head early '70's good 305.00 Traynor YGL-3A Mark Three 100 watt tube head w/rev.,trem. - good 396.00 Traynor YB4 1/15 50 watt tube combo - good 400.00
I haven't seen any of them in person, but the price on the Custom Special isn't bad.I just bought 2 amps from Song Bird Ottawa. Very nice folks to deal with. One was an early YGA-1 Signature, with a tube rectifier, the other was a 1974 YBA-1A.
The Signature is serial # 7619, fair condition, non-original grill cloth. The screws mounting the trannies are a bit rusty, and one of the OT mounts is sagging, but the amp is otherwise fairly clean.
The amp is set up for 7027 power tubes, and came with a well-toasted 5U4 rectifier, and equally toasted tung-sol and Roger's 6L6. This amp was sold as being in good working condition, but it cackled, cracked, and hissed, and howled with these tubes. I popped in a pair of used RCA 6L6's and a Chinese 5AR4, which improved the amp considerably, but I think it's still far beneath it's potential. All of the metal caps look pretty toasty, and should probably be replaced. The amp also, BTW, has a rather large, black choke, that also looks like the work of Hammond.
This amp cost $260 Canadian, a total of about $205 US to have shipped to the states. After seeing this amp, I have some doubts about the posts I've seen re: lower quality trannies in the later amps. The OT appears outwardly to be identical to the one in my 1973 YBA-1A, the PT being similar, but about half the size. I considered returning this amp, and waiting for a YBA-1 with the full eq, already set up with EL34's, and with a bit less wear, but just didn't get around to it quickly enough. The amp was a consignment item, and had not been serviced by Song Bird. I will probably have this amp converted to EL34's, diconnect the trem, and possibly use half the tube for an extra stage.
I received the YBA-1A yesterday. This amp cost $240 to have shipped to the states, and was over-priced, in my opinion. I received the amp yesterday, and it showed considerable wear, with quite a lot of rust on the jacks and switches. A section of the plates in the PT had slipped a bit, and one of the brackets on the fan was broken. The top mounting bolts were also excessively rusted, and had sunk considerably into the top. The amp belonged to Song Bird, and had a pair of Sovtek EL34's installed. I had the benefit of decent jpegs front and back before purchasing this amp, and was really surprised at how deteriorated it looked in person, so to speak. This is my second such experience with used amps, purchased from dealers, and I want to caution everyone not to rely very much on pictures transmitted over the web. They do NOT necessarily convey a realistic impression of the piece. I never even plugged it in. I repacked it and sent it back today.
The person I dealt with at Song Bird was Geoff Taylor, and I'm pretty impressed with the service I received. Both amps were shipped immediately, and were well packed. Song Bird has a 24 hour return guarantee, shipping costs paid by the buyer, of course. I called today and asked if I could send the YBA-1A back. No questions, no hassle, no BS, no attitude, no RA# required. Just send it back "and we'll refund your card when it gets here". Can't beat that.
One of the things that I've noticed about the Hammond trannies is how well potted they appear to be: not prone to deterioration due to rust. The only one I've seen so far that was maybe starting to show its age was the PT on the 1974 YBA-1A. I have a 73, and hung around the shop while my tech tried to crater the PT, and later took measurements off the OT while I played. Never seen better. He put some ridiculous load on the PT, and couldn't make it sag a bit. The amp was putting out a full 80 watts all the way down to 30-40hz, and up to 10K, with a signal generator. Maximum clean volume is at about 10-11 o'clock.
The fan is noisy and a bit decrepit, and I plan to relace it with a brushless model. FWIW, I've got the Svetlana EL34's in there, biased at about 39-41 ma, and these tubes run COOL with the fan blowing.