BIAS on H&K Triamp

[GodWentPUNK]

Hey all:

I'm thinking about new tubes for my Triamp and could not find any information about how to go about setting the bias on these heads. On my TSL, I had a trim-pot and little connectors to hook up my volt meter which made setting the bias an easy process.

I know the Triamp amp is NOT fixed bias so I will have to bias things when I replaces the tubes.

Has anyone done a BIAS on the Triamp that could give me some pointers.

thanks,

joe...

[SixstringKing]

I'd love to help you out but I've only needed to replace the preamp tubes on mine, still have the original power tubes in it. Maybe I'll take mine apart and have a look. Did you email their tech support? They are fairly quick in responding to emails.

[GodWentPUNK]

I did not contact their tech support. I'll give that a try.

What preamp tubes did you go with? Were you able to do anything with Channel 2/B to fix the muddyness????

joe...

[SixstringKing]

I replaced all the preamp tubes with Groove Tubes all were 12ax7. All the channels sound great!

[GodWentPUNK]

I'd love to help you out but I've only needed to replace the preamp tubes on mine, still have the original power tubes in it. Maybe I'll take mine apart and have a look. Did you email their tech support? They are fairly quick in responding to emails.

Ok, got a nice doc from H&K about some of the spec's on the bias settings. It did answer some questions so thanks for the suggestion.

This looks like a pretty neat tool. Will cost about $100 to bias a Quad

http://www.ebay.com/itm/Meter-QuadStage-BiasPro-Amp-Tube-Bias-Probe-Tester-Tool-/320764388559

joe...

[SixstringKing]

Sweet! I think I'll need to pick up one myself. Could you send that doc you got from H&K? Wicked amp eh!

[GodWentPUNK]

Here is the document from H&K. It's for all of their amps so you'll need to find the triamp1 section.

http://www.aidenterprise.com/gwp/TRIAMP_BIAS.pdf

joe...

[SixstringKing]

Thanks!


Allan

[SixstringKing]

Yeah, i have the MKII. I noticed that they like to keep the bias more in the middle instead of "pushing" the power tubes. I think I'm going tho get that meter off ebay and play around a bit with the bias on my amp and see what difference it makes.

[GodWentPUNK]

Me too. That tool is nice, however, they have one a little cheaper that you can hookup your own meter. I'm thinking of just spending the extra $$$ and getting the built-in one.

Also, H&K said that there in only one trim pot to adjust the bias on all of the tubes so I guess it's really important to make sure all of the tubes are really, really matched. On my TSL, I was able to adjust to outside and inside pairs independently because as you adjusted the outer set, it effected the bias on the inner pair. Hopefully with the Triamp, I will not experience anything like that, so I imagine all I need to do is hook up the tool to one tube and that reading will same for all of the tubes.

joe...