Thank you again for your response! I heard back from Koch and they've got them! Thank you again, your insight was incredibly helpful!
Enjoy the benefits of a premium membership!
Upgrade Account
-
TalkBass has been independent since 1998. Add your voice.
Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
Join free Log in
Want zero display ads or expanded classifieds tools? Compare plans.
The Un-Official Sadowsky SA200 Thread...
- Thread starter jokerjkny
- Start date
I'm a very very proud owner of a SA200 MK2 for a severzal hours now. This thread is a gold mine!
Are all MK2 equiped with KT88?
Is it necessary to bias the amp in case if tube swap?
About this particular point the manual says the following:
Replacing any tubes in the SA200 with the appropriate Sadowsky-approved tubes does not require any special adjustments to your SA200.
If I understand correctly, no bias is needed nor anything else?
Are all MK2 equiped with KT88?
Is it necessary to bias the amp in case if tube swap?
About this particular point the manual says the following:
Replacing any tubes in the SA200 with the appropriate Sadowsky-approved tubes does not require any special adjustments to your SA200.
If I understand correctly, no bias is needed nor anything else?
Last edited:
It sounds quite amazing yes! You don't have yours anymore?Enjoy the best! Best amp head i´ve ever had
Congrats!
Most likely the bias will need to be reset if the tube type is changed. AFAIK KT88 requires quite a bit higher bias the EL34. 25-30mA is the recommended current for both tube tubes.
I have a fresh set of unused Koch EL34s and the rating are different than the Koch EL34s in my amps, so it's likely that I will need to reset the bias if I ever used them.
AFAIK all SA200s shipped from the factory with Shuguang EL34B STR with Koch silk screening.
AFAIK the current recommendation from Roger Sadowksy is to use KT88 as the EL34Bs were running the screens to hard. I believe this recommendation comes from tube amp guru Blackie Pagano. No idea if Koch agrees.
Both of my SA200s are still running the OEM tubes. One has blown a HT fuse a couple times, and I plan to eventually try a set of KT88s. The problem stopped as soon as I quit moving the amp. Both amps are in permanent locations on a table. So it's possible the grid network in the tubes is trashed, or it may be the pins in the tube sockets are a bit loose. I'll experiment a bit to see if I can figure out which if I ever get around to rolling KT88s in the amp.
The threads where people converted to KT88 are all favorable. So the only disadvantage may be KT88s cost more.
Thank you for all these extremely valuable information!
I will open the amp to check but IIRC the MK2 were loaded with KT88 tubes.
Assuming those are actually KT88, will it still require a bias modification ?
I only have these image to go on.
Original
Mk2
Looks like EL34s in both to me. But maybe the Mk2 were shipped with KT88.
Roger Sadowsky said there is plenty of range in the bias circuit to run KT88 without modification. Ref: Sadowsky SA 200, is it THAT good?
That does not mean you don't have to make an adjustment.
My Sadowsky SA200 Mk1 failed soon after I purchased it NOS directly from Roger in 2017. Roger had me bring it to Blackie Pagano in NYC for the repair, at Roger's cost (Roger is A+ class). It was Blackie who switched my tubes to KT88, suggesting they sounded and work better with the amp. This was news to Roger, who then also began recommending KT88's for the SA200.
Maybe I should reach Blackie and ask Hime directly.
But I also need rack ears for the amp. And I'm in the Netherlands right now, where that amp was made. So I can reach them directly and ask them too.
But I also need rack ears for the amp. And I'm in the Netherlands right now, where that amp was made. So I can reach them directly and ask them too.
I recently got one of these too and it did not have the rack ears. I contacted Koch as was suggested in this forum and they were able send me a pair. If you call Koch you'll want to speak w Edwin Kool. He's there in the Netherlands. The rack ears will cost you about €40 or so.
That's exactly what I did and I got the ears for this price.
I could talk to a guy too about the next products.
They have some very interesting new designs for both bass and guitar amps.
They should be released for the next Namm show.
They are drifting away from tube amps. As the quality of tubes are getting lower and prices getting higher.
As it's my first full tube amp, what about this tube "fragility"?
Are tube amps THAT fragile or is it a myth? I'm fully awaure the amp MUST have a load nor you might destry the power section.
But I'm more talking about moving the amp, vibrations and so on.
About the needed load for a tube amp, I've read that it is actually possible tu switch it on without a load as long as you use the standby switch. Is this true?
Are tube amps THAT fragile or is it a myth? I'm fully awaure the amp MUST have a load nor you might destry the power section.
But I'm more talking about moving the amp, vibrations and so on.
About the needed load for a tube amp, I've read that it is actually possible tu switch it on without a load as long as you use the standby switch. Is this true?
Last edited:
Tube amps require more maintenance, but this is often related to tubes going bad. Tubes wear out and sometimes take other components with them.
To the greatest degree possible don't expose the amp to sharp and strong mechanical stresses.
After using the amp, turn it off and let it cool for a while before moving it.
An open circuit is the worst thing for a tube amp. Many older tube amps with 1/4" outputs use a jack that shunts the output to ground if you forget to plug a speaker in.
Can you turn a tube amp on without a load? As long as the amp is working properly and it does not have any signal applied, probably. But what if the amp has a problem. IMHO don't do it. If you do it by accident, set the amp to standby on as soon as you discover your mistake. Plug in your cab and then you can set the amp to operate. If the amp works fine, don't worry about it.
If you mean can you turn the amp on, but leave it in standby without a load, the answer is yes. But what if you forget to plug the speaker in before you set it to operate. IMHO, cultivate a good habit of doing things in the proper order, and accidents are less likely.
Thats what I wanted to know. But as you said, I must take good habits from the beginning.
Last edited:
Many years ago, I started the habit of plugging in the cabinet(s) BEFORE plugging in the power cord. I've never had a close call since.
