| Author | Message | ||
| wcv
New Username: wcv Post Number: 1 Registered: 4-2004 |
I am getting ready to re-tube my 400+. It came from MesaBoogie with 12AX7 & 6L6 tubes. The manual says use 12AX7 & 5881 tubes. I have visited many websites regarding tube characteristics, but they are all from a guitar point of view. Does anyone have recommendations for tubes for the 400+ from a bass players perspective? | ||
| alembic76407
Advanced Member Username: alembic76407 Post Number: 287 Registered: 5-2002 |
when I get home I will check my 400+ and see what Boogie sent me and let you know. David T | ||
| son_of_magni
Junior Username: son_of_magni Post Number: 38 Registered: 1-2004 |
My understanding is that the 5881 is the industrial version of the 6L6. They should be better balanced, lower noise, and possibly more power. But they will most likely be harder to find and cost 30-50% more. | ||
| dnburgess
Advanced Member Username: dnburgess Post Number: 252 Registered: 1-2003 |
The reference manuals confirm magnis understanding. e.g.: http://www.mclink.it/com/audiomatica/tubes/6l6.htm Also there are reviews of different tube types at: http://thetubestore.com/6l65881types.html The JAN-Phillips models seem to get the best overall review: "Price considered, it's the best available NOS of this type; it's all there. Champagne tone with a beer price." "American made with the vintage sound! I switched between the other brands and even had someone else do the switching and re-biasing while I closed my eyes to keep the test "blind" yet my ears could always hear that little bit extra that told me it was the Phillips tubes driving the speakers. Even when biased rather cold the tone still came through. It's a subtle difference that you may not immediately appreciate but the more you play the more you smile. Treat yourself!" I should have realised that tube type could make a big difference. When I had my old Bassman retubed a couple of years ago I didn't think of researching the space and got whatever the repair man thought fit to put in. I'll have to dig it out and have a look. | ||
| alembic76407
Advanced Member Username: alembic76407 Post Number: 288 Registered: 5-2002 |
Mesa/Boogie sent me 12 Mesa/Boogie STR 425 tubes, they told me they will run better and last longer(and they have)and that was from Mr Boogie himself, and as far as preamp tubes I just replaced mine with what was in there, 12AX7 I guess, it's been awhile. by the way, Welcome to the club!!! David T | ||
| gbarchus
Member Username: gbarchus Post Number: 59 Registered: 6-2002 |
Be sure and check out Svetlanas. I think they have (RCA) NOS characteristics. I use a Mesa/Boogie 180 power amp with an F2B. | ||
| goatfoot
Junior Username: goatfoot Post Number: 40 Registered: 12-2003 |
Hey guys, How heavy is your 400+? And what cabs are you playing it through? How's the sound? Found the perfect bass (Alembic, 'course) ... Still in search for the perfect rig. Kevin | ||
| alembic76407
Advanced Member Username: alembic76407 Post Number: 290 Registered: 5-2002 |
Kevin, the 400+ is about 35lb and I play through 2x15s and 2x10s (But there's allways Tornadic Thunder)for the speical gigs David T (TLO) | ||
| wcv
New Username: wcv Post Number: 2 Registered: 4-2004 |
First, thank you to all who responsed to my question regarding tubes for the 400+. As far as my set-up, I play through one SWR 2x10 and one SWR Triad (1x15,1x10,1xTweeter). I have these 4 ohm cabinets wired in series to run at an 8 ohm load. I was originally using a SWR Basic 350 (tube pre-amp & solid state power section)and found the Mesa 400+ (all tube with 12 power tubes)to have more headroom, punch, dynamic response as well as a more pleasing tone. | ||
| davehouck
Senior Member Username: davehouck Post Number: 504 Registered: 5-2002 |
Bill; just out of curiosity, why are you running your 4 ohm cabs in series? I see that the manual for the 400+ suggests that if you have two 4 ohm cabs you should connect them to the two 2 ohm outputs. I'm guessing you feel the 8 ohm load is safer. My initial thought was that running the cabs in series from one 8 ohm output would be less efficient. | ||
| wcv
New Username: wcv Post Number: 3 Registered: 4-2004 |
Dave you are right, even though the manual said that I can run a 2 ohm load, I (and others I consulted) felt an 8 ohm load was safer. I did find out quickly, that you need to make sure the speakers are in phase. I am curious about your thoughts regarding the effeciency, can you elaborate? I also have a third cabinet which is an 8 ohm cabinet that I was told I could combine with my existing set-up and run a 4 ohm load. Do you have any input regarding ohm loads and the quantity of drivers? For instance, in this scenario, Cabinet One:1x15,1x10@4ohm and Cabinet Two:2x10@4ohm in series are connected to Cabinet Three:2x10@8ohm parallel (or the two 4ohm outputs at the amp) for a total 4ohm load, is there any kind of imbalance (sound or electrical) between the cabinets because of the differing quantities and sizes of speakers in the cabinets? Thanks, Bill | ||
| davehouck
Senior Member Username: davehouck Post Number: 505 Registered: 5-2002 |
Bill; the scenario you describe with the three cabs is beyond my limited ability to think. No matter how often I read up on this type thing, I just can't seem to retain the information. One question that immediately comes to mind is how this arrangement effects the power handling ability of each of the three cabs. As to my comment about the efficiency; the specs of most power amps show that they output more power into a 4 ohm load than an 8 ohm load, and more into a 2 ohm load than a 4 ohm load. However, the manual for the 400+ says "the amp will produce its full power at all of these impedances [8, 4, 2], provided that the total impedance of your speaker cabinets is matched to the output(s) used". So perhaps it doesn't make a difference with the 400+. Again, this is beyond my technical expertise (or lack thereof). If Bob happens by this thread he's pretty good at this kind of stuff; as are a few others in the group. | ||
| hollis
Intermediate Member Username: hollis Post Number: 166 Registered: 11-2003 |
Hi, It seems to me that if you run all three cabinets in parallel you end up with an 8 ohm load...... go to: http://www.mikelights.com/speaker1.html I think what he's saying is (R1XR2XR3)/(R1+R2+R3) It looks like an 8ohm load to me........ | ||
| hollis
Intermediate Member Username: hollis Post Number: 167 Registered: 11-2003 |
By the way, thanks for the heads up about the tube store, I ordered a whole mess a tubes from them yesterday, and they're on there way today...very cool place. | ||
| wcv
New Username: wcv Post Number: 4 Registered: 4-2004 |
Hollis and Dave, Thanks for the input, this stuff is difficult for me also. And it looks like in this case I made it more complicated than it had to be. But now that I've seen the formula, I agree with Hollis, it looks like an 8 ohm load wired parallel. Thank you to the Alembic Club, it's a great resource. I hope I be able to return the favor by helping someone in the future. Bill | ||
| adriaan
Advanced Member Username: adriaan Post Number: 210 Registered: 6-2002 |
My English maths expressions are not up to scratch, and I know there are others who know much better than I do, but this is what I remember from my schooldays: Loads wired in series add up, like (R1 + R2). Loads wired in parallel go like (1/R1 + 1/R2) and then you turn the resulting fracture on its head and you have the end result. Loads wired in series, as a branch of a parallel load, are regarded as a single load. If you put the 4 ohm cabs in series, and wire that in parallel with the 8 ohm cab, you get: 1/(4+4) + 1/8 = 1/8 + 1/8 = 2/8, make that 8/2 - that's 4 ohms. If you put the 3 cabs in parallel, you get 1/4 + 1/4 + 1/8 = 2/8 + 2/8 + 1/8 = 5/8, make that 8/5 - that would be 1.6 ohm, not 8 ohm. Hollis is right that Mike's formula (R1xR2xR3)/(R1+R2+R3) translates to (8x4x4)/(8+4+4) = 128/16 = 8 ohm - but I just don't know if that's the appropriate formula. | ||
| son_of_magni
Junior Username: son_of_magni Post Number: 39 Registered: 1-2004 |
adriaan is exactly correct... "Loads wired in series add up, like (R1 + R2). Loads wired in parallel go like (1/R1 + 1/R2) and then you turn the resulting fracture on its head and you have the end result." To be more clear 1/(1/R1 + 1/R2 + 1/R3...) = n where n is the resulting parallel value. For example if you have two 4 ohm and one 8 ohm speaker: 1/(1/4 + 1/4 + 1/8) = 1/(.25 + .25 + .125) = 1/.625 = 1.6 ohms (Message edited by son_of_magni on May 05, 2004) | ||
| hollis
Intermediate Member Username: hollis Post Number: 169 Registered: 11-2003 |
Ummmm.... hmmmm...... I'm sooo confused! | ||
| adriaan
Advanced Member Username: adriaan Post Number: 211 Registered: 6-2002 |
It's better to be confused than to have your speakers fried or your amp up in flames of glory, is it not? | ||
| hollis
Intermediate Member Username: hollis Post Number: 171 Registered: 11-2003 |
That is something that I am fully upright and at attention about. Yessirree, you are correct sir! Thanks for the detour sign along my thought's highway.... | ||
| wcv
New Username: wcv Post Number: 5 Registered: 4-2004 |
I used to think ohm as a mantra...not something to cause a headache...although I do feel, some how enlightend...ohm... I get it, I think...at least I should be able to prevent an unexpected pyrotechnic display and cancellation of a gig. Bill | ||
| adriaan
Advanced Member Username: adriaan Post Number: 215 Registered: 6-2002 |
Hollis, When in doubt, skip my contributions. It works for me too. | ||
| adriaan
Advanced Member Username: adriaan Post Number: 219 Registered: 6-2002 |
Beware, this is the voice of inexperience speaking. The above formulas are for wiring up resistors in parallel and in series, and any combination thereof, but only in a laboratory situation with everything hooked up to a single power outlet. The same principles apply to connecting speakers to an amp, except that if the amp has multiple outlets then they are probably wired in parallel, and when you connect cabs to separate outlets then they are included in separate branches of the parallel circuit. In any case, any halfway decent amp will have markings telling you the minimum and maximum load per outlet and/or channel, and probably also the minimum total when using more than one outlet. If you start daisy-chaining your cabs, then you'll have to check the documentation of the cabs if that creates a parallel or a series circuit, then do the maths to see what load it creates for the amp. | ||
| basso
Junior Username: basso Post Number: 43 Registered: 3-2004 |
I used svetlana russian tubes when i had my boogie, both for preamp and power amp,the first time i replaced them i bought the boogie brand,and then found out that they are indeed svetlana,they just put their name on them,the tubes did have made in russia printed on them!i didn't have any problems at all with them,hope this helps. | ||
| wcv
New Username: wcv Post Number: 6 Registered: 4-2004 |
Adrian, Thanks for the heads up on which formula to use and the bit about the wiring of the cabinets. I'm not sure it would have occured to me, to check if the in/out of the cabinets wired series or parallel. This gives me a good start, and with a little patience, I think I can work the math out. | ||
| wcv
New Username: wcv Post Number: 7 Registered: 4-2004 |
Adriaan, sorry about the typo...I'm quite new to this, is there a way to edit a post once it is up? Bill Never mind, I found it. (Message edited by wcv on May 07, 2004) | ||
| wcv
New Username: wcv Post Number: 8 Registered: 4-2004 |
basso, Thank you. From the responses to my original post about tubes, it looks like a shoot out between Svetlanas and JAN-Phillips. With an edge to the Svetlanas, but the review of the Phillips tubes sounds interesting. hmmm..... | ||
| hollis
Intermediate Member Username: hollis Post Number: 181 Registered: 11-2003 |
Bill, Click on the pad and pencil in the upper right of your post to edit. | ||
| adriaan
Advanced Member Username: adriaan Post Number: 222 Registered: 6-2002 |
Hey Bill (wcv), You must be the first American to even notice there's three A's in Adriaan - you score big time! Others have been known to think I'm a female of the species - but no, I'm just (not) funny that way. I've owned two tube amps. One had no less than 2 EL84 tubes in the end stage, not sure about the brand though - may well have been Svetlana - and they put out about 30 watts of pure tone into an 8 ohm 80 watts full-range speaker (Fane Disco 80) in an undersized cab. If it was anything, it was not loud. But it had the sweetest highs - no sizzles! I've been told the high end purity was due mostly to having a relatively high-end end transformer (Unitran) coupling the amp's end stage to the speaker. The rest of the amp was - spartan, for want of a better word. The other tube amp was a Marshall 100 watts, presumably a late 1970s model. It was loud enough for what I was playing at the time, but don't ask about the tone. Though it could have been the 15" EV ruining the tone, I don't (care to) know. |
