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Traynor YBA200-2 tubes and maintenance

O

OleJohnnyMac

Jan 19, 2011
70
0
Moose Lake, Manitoba
#1
I know there are a couple of YBA200 threads on here but I haven't found one that deals with this specific issue. Also, I'm on dial-up because I live up north in the woods, so extensive searching of the forums can be very time consuming.

I'm thinking about picking up a YBA200-2 (*after* I upgrade my TB membership, obviously) and I'm wondering two things: 1) how much does it cost to keep tubes in it; and 2) how often would I have to get it re-biased? The nearest tech is probably at Long and McQuade in Winnipeg, which is about 7 hours away, and to be honest, I'm not even really sure exactly what re-biasing entails.

I like the tube sound, but I'd rather not be stuck in the middle of nowhere with an amp that doesn't run for months at a time. Are there any tube heads out there who can give me some advice?
 
#2
I'll take a stab at this: I don't have that exact amp, but I do have many tube amps in my collection, the large output tubes should last many years once they are set-up and biased, think of biasing, as setting the idle on your car, you don't want it too low or too high ... the type of output tube in that amp can be a 6550 or a KT-88, they came with both from the factory at one time or another, just buy your tubes from a reputable dealer, cost is about $30-$35 each , there was a thread about changing one of the preamp/ driver tube, to get some more clean headroom ... hope this helps
 
#3
Maintenance shouldn't be too high at all, a decent matched pair of KT88 would probably run you 70~90 bucks, cheaper if you get factory seconds. Re-biasing a believe adjusts the plate voltage to suit different types of tubes and to ensure optimal operation. Retubing should be good for years, depending on how hard you drive it of course.

Changing preamp tubes is easy and doesn't require a rebias.
 
#5
OleJohnnyMac said:
I'm thinking about picking up a YBA200-2 ...to be honest, I'm not even really sure exactly what re-biasing entails.
Click to expand...

Tubes can last for many years. If you can afford it, keeping an extra set on hand never hurts.

The bias is checked when you replace your power tubes. The bias can change a bit as the tube ages. Some people like to check the bias every year or so to ensure it is optimally set.

The most basic way of setting the bias on a YBA200 involves opening up the amp and measuring a voltage at four test points relative to ground. The readings should be 75 milliVolts +/- 10mV. A pot on the circuit board is adjusted to put you within that range. It isn't difficult to do.

You don't have to go to a musical instrument store to have this amp serviced. If there is a ham radio operator that works on their equipment, an electronics repair guy, or even a radio station in your area, they might be able to help you.
 
#7
Alex1984 said:
Maintenance shouldn't be too high at all, a decent matched pair of KT88 would probably run you 70~90 bucks, cheaper if you get factory seconds. Re-biasing a believe adjusts the plate voltage to suit different types of tubes and to ensure optimal operation. Retubing should be good for years, depending on how hard you drive it of course.

Changing preamp tubes is easy and doesn't require a rebias.
Click to expand...

What use is a matched pair of KT88s for an amp that runs four 6550s? Biasing has absolutely nothing to do with adjusting the plate voltage. It has everything to do with controlling the current flowing through the tubes and thus the power being dissipated by the plates.
 
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#8
actually the YBA200-2's come stock with KT-88s and not 6550s as Traynor blames 6550s for the meltdown issues the non "-2" model had. I used to own one and was talking to Traynor's service dept. about this. I actually talked with the head service guy (cant remember his name) about this because I had an amp that was labeled a YBA200-2 but actually had the guts of a YBA-200, in other words it was self biasing when it shouldnt have been!! I was talking to them about how this couldve happened and getting the 'upgraded specs' work done. He told me that as long as I was running KT-88s it shouldnt be an issue because KT-88s, unlike any current production 6550, are relatively stable to the amount of 'drift' seen in 6550s. He said that the meltdowns were happening only in amps with 6650s cos, in his words, no current 6550 tubes are actually made to the correct specs to prevent an unacceptable amount of 'drift' from their set bias. Traynor made the switch to KT-88s then, even though the newer models were manual bias, as they just thought it was overall better for the amp over time.

again, this is what they told me and I have to take their word to some degree cos I dont know enough (nearly as much as you Paul) about the finer electrical workings of tube amps. btw.. I dont believe this was any kind of diversionary explanation on their part because they offered to do the upgrade work as a 'warranty' request at no cost to me.
 
#10
eyeballkid said:
btw.. you dont need a supporting membership to buy thru the classifieds... just to sell..but being a supporter is definately a cool way to support the resources here!
Click to expand...

I realize this. I don't intend to upgrade my membership in order to do business on TB. I just thought that anyone (i.e. me) whose post indicates that he has money to spare for an all-tube bass head ought to feel a bit sheepish about not financially supporting the useful and diverting bass forum that enables him to write such a post in the first place.

I think it's great that TB is free, but I believe in paying to keep stuff free, if that makes any sense.

Thanks for all the responses, TB'ers. I'm thinking about the VB2 as well, but they're rarer in my neck of the woods. We seem to be up to our knobs in Traynors here in Canada.
 
#17
A rep fromLong and McQuade, who is a user here, had been very helpfull in resolving a problem with the service dept for a 2010 issue with my YBA200 over a year ago. The end result was that the amp was modified to be a YBA200-2. Thread links:

http://www.talkbass.com/forum/f15/traynor-yba200-tweaks-observations-150395/index4.html

http://www.talkbass.com/forum/f15/traynor-yba-200-tube-upgrade-362851/index3.html

http://www.talkbass.com/forum/f15/traynor-yba-200-thread-255204/index14.html


Last week, I had an output tube go bad which damaged R66. Loud pop and a flash! I replaced R66 with an equivalent 2ohm 2W 1% metal film Vishay resistor. It failed again. I put in my original 6550's, as replacing them did not resolve the 2010 issue I had. The resistor did not get damaged this time. On the original tubes wivh are now in the amp, ll the voltages on the bias test points are within 10mV of each other but the lowest in 90mV. I read in this thread, which that the YBA200-2 should be using KT88's. Is this why my bias test voltages are high? If anyone can please advise me, I thank you very much for your time!
 
#19
beans-on-toast said:
The most basic way of setting the bias on a YBA200 involves opening up the amp and measuring a voltage at four test points relative to ground. The readings should be 75 milliVolts +/- 10mV. A pot on the circuit board is adjusted to put you within that range. It isn't difficult to do.
Click to expand...

Thank you! lol I've been searching for this for a while now. I liked how my previous SVT had the self biasing on it and I was hoping that I would still be able to check the bias myself with my YBA200-2.
 
#20
This question is for @BassmanPaul or @beans-on-toast. Feel free to jump in if your know as well though! I opened up my YBA200-2 to check the bias. Just because it's new and so I would have a reference for down the road when I need to change a tube or whatever. Anyways my results were as follows
20170917_090544.jpg


The service manual says set to 75mv +/- 10mv. The V4/V7 pair seem ok just over 70mv.. But the V6/V5 pair seem low the V6 almost 13mv. The bias control pot is as high as it goes (was already set that way) and I did lower it and raise it back up and watched the values move. Is this normal? My last head was a SVT-cl so it was much easier to set the bias lol.
 

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