mustang guy Posted September 22, 2011 Share Posted September 22, 2011 I just purchased a Pioneer SX 800 receiver from a forum member, and when it got here, one of the tubes had wiggled out of the socket, and the top is broken. I looked at it, and it is an EL84/6BQ5, and it is supposed to be a 7189A. I understand the 7189A is kinda rare, and many amps are reworked to accept other tubes. Before I go buy a pair of EL84's, what should I look for? I turned on the receiver, and it powered up with only one speaker working, then the busted tube finally started blinking, so I turned it off real quick. Where is the best place to get EL84 tubes? The ones I have are Sovtek's. edit: I am a Tube Nube. Sorry, I couldn't help it. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted September 22, 2011 Share Posted September 22, 2011 the sovtek are probally 6BQ5 6N14N-EB, a good replacement for 7189a and 7591a (EL-84M) . if you go straight el-84, one area of investigation is the plate voltage since the 7189A is really a hi voltage el-84. Not all straight el-84's can sub for 7189A's due to the plate voltage differences. Quote Link to comment Share on other sites More sharing options...
Marvel Posted September 22, 2011 Share Posted September 22, 2011 Where is the best place to get EL84 tubes? The ones I have are Sovtek's. There are a number of places... I have used The Tube Depot and been satisfied with the service and availability.http://www.tubedepot.com/ the sovtek are probally 6BQ5 6N14N-EB, a good replacement for 7189a and 7591a (EL-84M) . if you go straight el-84, one area of investigation is the plate voltage since the 7189A is really a hi voltage el-84. Not all straight el-84's can sub for 7189A's due to the plate voltage differences. Everything I see on a 7591a show it is an octal, and not a nine pin. Bruce Quote Link to comment Share on other sites More sharing options...
Guest " " Posted September 22, 2011 Share Posted September 22, 2011 Everything I see on a 7591a show it is an octal, and not a nine pin. thats right it is...typo Quote Link to comment Share on other sites More sharing options...
T2K Posted September 22, 2011 Share Posted September 22, 2011 I think I have a quad of GE 7189a and several quads of RCA 7189/6bq5. I'm not willing to give them away but if you're interested let me know. Keith Quote Link to comment Share on other sites More sharing options...
mustang guy Posted September 22, 2011 Author Share Posted September 22, 2011 According to http://www.bustedgear.com/res_Tube_7189.htm, the pinouts of the 7189a differ from the EL84 and 7189. I assume the EL84M is the same pinout as the EL84. What about the 1/2 and 6/9 pin differences that sometimes occur? Quote Link to comment Share on other sites More sharing options...
mustang guy Posted September 23, 2011 Author Share Posted September 23, 2011 bump cause I still need help... see message above this one... Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted September 23, 2011 Share Posted September 23, 2011 This receiver runs the output tubes very hard (i.e. plate voltage actually exceeds the design maximum value by a few volts). I'd definitely stay with the 7189A. NOS tubes can be quite costly, so check the specs of the replacements currently being manufactured to be sure that the rated plate voltage is around 440-450, with a plate dissipation of 13 or more watts. Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted September 23, 2011 Share Posted September 23, 2011 A couple of places which have the 7189A: https://www.tubeworld.com/7189.htm http://www.tubedepot.com/pe-7189a.html http://www.tubemonger.com/NOS_NIB_Siemens_E84L_7320_prem_EL84_Munich_Prod_p/451.htm Quote Link to comment Share on other sites More sharing options...
mustang guy Posted September 23, 2011 Author Share Posted September 23, 2011 I'm looking seriously at EL84M's. The 7189a's are pretty much extinct and thus overpriced where they are availible, and the M's are more durable than the regular EL84's. The thing came to me with regular EL84's, so maybe somebody lowered the plate voltage already. I can flip it over and try to figure out what it is. Any tips on measuring the plate voltage other than don't shock the crap out of yourself? Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted September 23, 2011 Share Posted September 23, 2011 If you are not familiar with proper safety precautions for working with potentially lethal voltages, don't try it! Where are you located? Perhaps there's a knowledgeable forum member in the area who can check this for you. Quote Link to comment Share on other sites More sharing options...
mustang guy Posted September 23, 2011 Author Share Posted September 23, 2011 I am in Parkersburg, WV. I am not excited about the possibility of a capacitative discharge from filter caps. Perhaps there is a tech here in town I can take it to. There is an electrical appliance repair shop, so maybe they can. Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted September 23, 2011 Share Posted September 23, 2011 If you try the repair shop verify that the person who checks it is familiar with vintage tube type electronics. A possibly better alternative is to find a local ham radio club which is sure to have some "old timers" (like me!!!) who are very familiar with tube electronics and their associated high voltages. Hams are generally more than willing to help out anyone who asks, and the collective knowledge in many clubs is quite formidable! Quote Link to comment Share on other sites More sharing options...
mustang guy Posted September 23, 2011 Author Share Posted September 23, 2011 That's good advice. I will do just that. Quote Link to comment Share on other sites More sharing options...
mustang guy Posted September 23, 2011 Author Share Posted September 23, 2011 I can get matched el84m's for a reasonable price. They are 400v rated, so they will last a while. I figure the regular 300v EL84's lasted a while for the last owner, what have I got to lose. Those were first mentioned by SF, so I gotta think they will do fine. Quote Link to comment Share on other sites More sharing options...
mustang guy Posted September 23, 2011 Author Share Posted September 23, 2011 tubedepot had them in matched pairs. I ordered two sets, and noted to make a matched quad if possible. Total price $54.85 including FedEx 2-4 day shipping. Not bad. Thank you guys! Quote Link to comment Share on other sites More sharing options...
T2K Posted October 21, 2011 Share Posted October 21, 2011 I take it you no longer want the quad of GE 7189A tubes. I mean, its been a month... Keith Quote Link to comment Share on other sites More sharing options...
mustang guy Posted October 21, 2011 Author Share Posted October 21, 2011 Oh gosh, I forgot all about that. I put the EL84m's in, and it sounds beautiful. I suppose you can hold on to them, as the new tubes seem just fine. Perhaps there is another forum member faced with the same problem, and needs some 7189A's. And a matched quad no less. Thanks, and sorry about that! Quote Link to comment Share on other sites More sharing options...
T2K Posted October 21, 2011 Share Posted October 21, 2011 So in other words... no. I pretty much quit selling things that I don't need here. More trouble than it's worth. Keith Quote Link to comment Share on other sites More sharing options...
DanO55 Posted October 22, 2011 Share Posted October 22, 2011 Amen on that brother. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.