Hi I’m just thinking ahead right now . I’m not su
re how long my 2 90 2 will go before it needs tubes . I don’t use it every day so I’m guessing it will be awhile before I need it biased? Anyways I was reading what people had to say about getting it biased some people do it them selfs ,I’m not one of those people lol I’m afraid I’ll blow myself through a wall . But I’m worried about who l can trust here to drop it off and bias it and then pick it up I’m out side of Detroit in Lincoln Park Michigan . 48146 . I was wondering if you guys know of any dealers that are around here that have a good reputation with your power amps . ? I also read people saying that they had to remove the fan to use the bias probes . Does that sound right ? I’m worried after I need this biased ill get back a mess . It sounds like people that tried to bias had a lot of issues and trouble finding the pot to change the bias and what to bias it to
. I’m hoping this is all just crazy internet stuff and that there’s some one around me that can bias this easily ! I also read some one said that I could call you guys and get the same tubes again at the same tube value and no need to bias . Is this correct . Sorry about all the questions and need for advice I just really love this amp and all my fryette gear . Id appreciate any help and advice very much . Thank you for any help
No need to do anything unless you change tubes. That would typically be years away, so I wouldn’t concern yourself with this on a brand new amp.
Cheers,
Dave
Thanks Dave I also heard this that you can send a pair of the current tubes to a supplier who can rate them and send you equivalent matched sets and not need to bias if they send the same rated tubes . Is that correct? Sorry the problem is I don’t drive because my eyes aren’t good enough to pass the test . And I’m not sure who is familiar with working on these in Detroit . Thanks again for help ! And I’m really glad it will be a while before I need to address this . It will hopefully give me time to find some one I can trust to work on it . Thank you
Rick,
No need to send tubes anywhere to get tested or rated. You just need to give the supplier the rating number on the tubes and they would be able to get you in the ball park.
Keep in mind that this is not a foolproof way to do things as all suppliers use slightly different procedures for rating their tubes. The best thing to do is re-bias when the tubes require replacement. The idea is that they would last long enough that by the time you need to change them, it is time for a re-bias anyway.
You can contact Bruce Egnater in Oak Park if you ever need local servicing or maintenance on these.
Dave
Thank you is Bruce still working on amps ? I thought I heard isn’t but maybe I’m thinking of someone else . Last time I needed a head biased I called so many highly recommended techs like Bruce and a lot of them were retired or getting ready to . Lol that’s my problem here not enough good amp guys . That’s why I’m thinking ahead about what to do when this needs to be biased . And my eyes are so bad I can’t pass the eye exam to drive so created a new problem for me . Getting old sucks lol . I guess since it will be a while before this needs new tubes I can always just get back with you guys then . Thank you very much for help there has to be done way I can keep this working and biased when it needs it . I love this amp it will be a permanent part of my rig do I have to figure something out . I was told before I bought it when I called you guys that any amp guy should easily be able to bais it . And it wouldn’t be a big deal . I hope that’s the case and all the craziness I’m reading about biasing them is just Internet nonsense thank you
There is a lot of nonsense out there, which is why we are creating this safe space here.
Bruce is still active and we do refer repairs to him from time to time.
Dave
Hey Rick,
3, 2, 1… breathe … go for a walk outside …
OK so you can easily find an amp tech near you. I just did a google search and found a few that seem very reputable. We will always work with reputable techs, to give them what they need, you are our customer and we want to look after you.
Excuse my flippant reply… experimenting with being more malcontent… 
L0l ok your right I need to breath ! You nailed it really that’s the problem here especially when I like something as much as I like my fryette gear then read all that nonsense that gets my gears winding in my mind and causes all the anxiety . And then all I want is to know it’s all good ! Lol that’s was great though the breath advice ! Thank you Dave . I appreciate all the help lol wow sorry I meant thanks Dan !
Sorry I hope you see i fixed that last response and said thanks DAN lol really thank you so much . And sorry I got confused between the responses from Dave and you . It’s my eyes I can’t see well and I’m never wearing my glasses and even then it’s not that great . Thank you again DAN !!! Lol and thank you too Dave !that was funny experimenting with being more malcontent it seems to have worked out great for Steve so why not lol
Hi Rick,
Everything is fine. I’m glad you love your Fryette gear so much, you made me smile.
Regards,
Dan
Can someone please provide the location of the trim pots schematic and starting values for biasing the 2/90/2? It is not in the manual and would like to have this information for when the time comes. Please.
When you open the top and look at the main board, the bias pots, which are located on the rear left area of the main board are easy to spot because they are the only variable pots on the board, and they are each marked the this text: BIAS.
We normally start a new unit in QC with the pots set in the halfway position, but that’s unnecessary when replacing tubes. You can simply start with the existing position and tweak accordingly, or go back to the mid-point and adjust from there.
We set the bias according to the procedure attached.
Dave
2902Bias.pdf (50.2 KB)
I got a set of 6550 tubes from Fryette a few months ago as mine failed along with the fuse immediately upon firing the amp for the first time. Does that meant that I have to bias it?