Ampeg BA-108 Coffeeshop Micro Rig

[deepestend]

If anyone has an 8" that they have tested and didn't love or has an extra, get in touch. Working on my own 8" build right now.

 

[DM3O]

The B-100R preamp is similar to the B-50R, but slightly more complicated. Both get good compliments on their tone. So it seems that the BA-108 and 110 might be able to improve their tone by adding a limiter circuit. At first, I was looking to mount it inside, but for now, I'm just making a box to use in the effects loop. You could use an existing pedal if you want, but I'm trying to get close to the B-50R/B-100R circuit.[/QUOTE]

Woodstockz, couldn't find if you installed the limiter circuit on the BA-108. Can you post pics of this mod?

 

[Woodstockz]

The B-100R preamp is similar to the B-50R, but slightly more complicated. Both get good compliments on their tone. So it seems that the BA-108 and 110 might be able to improve their tone by adding a limiter circuit. At first, I was looking to mount it inside, but for now, I'm just making a box to use in the effects loop. You could use an existing pedal if you want, but I'm trying to get close to the B-50R/B-100R circuit.

Woodstockz, couldn't find if you installed the limiter circuit on the BA-108. Can you post pics of this mod?[/QUOTE]

Thanks for the bump. This was a fun project. I have a couple more projects in the works. I have been out of the loop due to my move, so I have a hard time keeping up. I had to put things in storage for a while while the new place was being finished, then we had to sort through everything to get settled. I am just getting my new skunkworks (garage) set up for new projects.

Also, I can't reach TB from my job any more, which is probably a good thing.

The B100R, BA-112 and the Markbass 601/801 were my inspirations for the project.

I never finished the compressor. I ordered the parts, but they are buried somewhere in some box in the garage. I re-evaluated the project and decided that since the heatsinks are inside the electronics box and there is no fan or ventilation, that the project could only go so far.

I also looked at my needs in order to prioritize my projects.
Home practice - I figure that the first step in getting great tone is hitting the right notes.
Band practice - A little bit louder now.
Gigs - A little bit louder now.
Hey, hey, hey, hey.....Oh, sorry. I got carried away.

Each one of these steps has some cool project opportunities. Here is the latest status of the BA-108 project (Sorry for the crappy cellphone pic):

 

[DM3O]

LOL. Home practice...bullseye! It would be nice, real estate provided, to fit in a scrambler circuit like in the new BA series. Really nice thread. I bought my BA108 a year ago; from the first time I used it this amp seemed to me like a little beast in the making. I thought that most surely someone, somewhere must have upgraded it...and here I am proving me right. All posts have been helpful. Now I'm enjoying my amp even more. Later on I will post some pics of my BA108 project.

 

[Woodstockz]

I also figured that a compressor or limiter pedal would work in the effects loop. I still might do it later, along with some other features.

Ampeg/Loud did an amazing job to get the price of the BA-108 down to $100. The stock speaker is OK, but not stellar. Generally, stock combo speakers have small voice coils.

Ukiah Bass had the idea to put a Faital 8PR200 from a Crazy 8 into a BA-108. He wasn't serious, but I thought about it over and over.
I just couldn't get the idea out of my head, and had to do something. But the Faital was way too expensive, so I found this for about half the price:
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Not exactly the Faital, but The B&C 8NDL51, with an Xmax of 7 mm, not bad for a poor mans Crazy 8.

 

[bnolsen]

Not exactly the Faital, but The B&C 8NDL51, with an Xmax of 7 mm, not bad for a poor mans Crazy 8.

since i'm lazy how would this compare to an alpha 8a?

 

[Woodstockz]

since i'm lazy how would this compare to an alpha 8a?

I haven't heard either yet. I haven't bought an alpha 8, and the B&C is under construction. But for now, we can look at some specs.

Both have about the same sensitivity at 94 dB. The Alpha has a 1.5 inch diameter voice coil and xmax of 3.2. The B&C has a 2 inch voice coil and more than twice as much xmax of 7, so it will push more air, if given enough power to reach xmax. (Yeah, I know, manufacturers measure these things differently, but you have to start somewhere).

The Alpha 8 is only 50 bucks. I have a rotator cuff issue from throwing a lot of footballs, so I always pay a more for the neo magnets.

For now, my BA-108 is development equipment; I plan to use the BA-108 effects loop to develop some circuits that I have been thinking about. I also plan to make a few tests with the poor man's crazy 8 cab to measure it's performance.

I can't say enough about the S2010 Basslite. It gives you a lot of bang for the buck. I have used my BA-110 loaded with the S2010 at jazz practice and jams regularly for the past couple of years. This week, we had a guest bass player who played his 5-string through it. I often get complements on the amp. I wish that they made an 8 inch version.

 

[bnolsen]

It's a shame that you can't use the effects loop at the same time as an AUX input.
My ba108 with an alpha 8a in it does a good job with full and short scale 4 strings.
Not so great with a ubass or an active 5 string.

 

[Woodstockz]

It's a shame that you can't use the effects loop at the same time as an AUX input.
My ba108 with an alpha 8a in it does a good job with full and short scale 4 strings.
Not so great with a ubass or an active 5 string.

Ampeg has an HPF that rolls the BA-108 and 110 off below 80 Hz. It's OK for a 4 string, but you miss both the fundamental and first harmonic on a low B.

The other bass player was all over the fretboard. He played walking bass lines, and soloed in the upper registers. By not banging on the low B, he sounded OK.

A mod to roll the HPF off at 60 HZ instead of 80 HZ would be cool for 5 stringers.

 

[pie_man_25]

I just finished reading the entire threads, just got some inspiration to do my own small bass amp stuff... look what you've done!

I've found a BA110 V1 locally, but the guy won't accept 100 for it. Not sure if I should go for it or not. This has made me want to either lightly mod a BA110/108, or grab a REALLY cheap used no-name 15-watt amp, guitar or bass, mod the EQ and power sections for bass duty, and build a new cab for both the amp and speaker from some particle board leftover from a 110 cabinet that I had built at 15 with no budget (speaker was an old hi-fi speaker that I blew).

 

[jledouxart]

Ok, I took the rectifier off the main board and added a daughter board with two 2200uF capacitors in parallel with the existing ones. That fixed the whole buzzing problem.
In addition, this mod made a huge difference. This little beast booms my ass off now. This is how I solved it:


[Invalid or Expired Link Removed]

I used stripboard to mount the rectifier and additional filter caps. In my opinion, this mod affected the sound far more than swapping the speaker.

I have read this whole thread and appear to be having the same problem VeskuFIN had and not the cabinet rattle that so many others have been able to fix. I bought used from Clist and didn't notice the buzz until I got home. After reading up on the buzz/rattle issue I glued all of the seams and added some 1" foam to the interior. This had no impact on it. I thought maybe the speaker had a small tear in it, so I temporarily swapped it out with an 8" from a Rumble I have. It made the same noise, so it is not the speaker. In the very short video linked below I am holding the speaker in my palm (not touching the cab) and have the amp turned up to a 3 and you can hear the "electronic buzz" when striking the open E. I have not been able to get this to replicate through headphones. I am not confident in knowing how to do what VeskuFIN has done; I can solder to some degree but wouldn't know where to start. Is this something that I should try to have repaired or should I cut my losses and move on? Note: I only intend to use this for personal practice at my home, I like the stock tone of this amp and generally would not turn it up louder than 3...but that BUZZ?!?!

 

[DrummerwStrings]

A gentle bump to an interesting thread. I'm a beginner guitar player who initially came to TB while searching for practice amp mods - an Ampeg combo? - and several long nights later I'm a new TB member constantly checking Craigslist.

Thanks for the inspiration - I found a mint BA-108 v1 for $45, & as I enjoy playing it I'm planning which mods to try. First will be dealing with the hum, but I've already learned a lot about matching speakers to cabs as I decide which speaker to swap to. There's no rush to cut into a fine amp. Circuit mods are postponed until I brush up on all the electronics I forgot.

Please keep experimenting & posting your results, people are watching.

 

[pie_man_25]

I have read this whole thread and appear to be having the same problem VeskuFIN had and not the cabinet rattle that so many others have been able to fix. I bought used from Clist and didn't notice the buzz until I got home. After reading up on the buzz/rattle issue I glued all of the seams and added some 1" foam to the interior. This had no impact on it. I thought maybe the speaker had a small tear in it, so I temporarily swapped it out with an 8" from a Rumble I have. It made the same noise, so it is not the speaker. In the very short video linked below I am holding the speaker in my palm (not touching the cab) and have the amp turned up to a 3 and you can hear the "electronic buzz" when striking the open E. I have not been able to get this to replicate through headphones. I am not confident in knowing how to do what VeskuFIN has done; I can solder to some degree but wouldn't know where to start. Is this something that I should try to have repaired or should I cut my losses and move on? Note: I only intend to use this for personal practice at my home, I like the stock tone of this amp and generally would not turn it up louder than 3...but that BUZZ?!?!

I wish I could tell you exactly what is causing that buzz, perhaps one of the ICS or transistors is clipping, might be a cold solder or under-spec part, or possibly some dirt in the potentiometers. Maybe just cleaning the potentiometers with some contact cleaner or wd40 could work, though I doubt it's that exactly. Maybe the leads for the speaker are shorting a little bit, might want to check that out.

Edit: you could try cleaning the contacts on the jacks for the effects loop if there is one.

 

[NanoGR]

Hey everyone, how are you doing? I bought a BA108 last week because I was expecting to do so for like a month , and as I had an extra 8" speaker, I googled BA108 upgrades and stumbled upon this post, before buying the combo... I found all the tips completely useful and encouraging so I went to get the amp really excited about it. First thing I did when I got to my house was play with the stock speaker to hear how it sounded before I did the upgrade, but it didn`t took much for me to pull the grill and do the mod. Placed a JBL 8PW7 ( Link Removed ) woofer, and REALLY LIKED IT! First thing I noticed was that I was able to crank the volume up to 8 without fart, and also that a lot of clarity was added to the sound. All subjective, but anyways, a huge difference... However, I started to hear some rattling so I am thinking to glue all the seams tonight, so it can harden overnight and test it tomorrow morning.

In the specifications of the Speaker it suggests that with a vented box enclosure I should have 19 liters of internal volume (which is a bit less of the 0.7 cubic feet this amp has) and a port/duct of 3" in diameter and 2" long. As the Ampeg has an 3"x3" I am thinking on trimming an inch... what do you think about it?
As i live in Argentina and imported products are banned, I cannot purchase flared ports, so im staying with the stock one, trimmed.

I have an Aguilar Tone Hammer preamp and plug it into the FX LOOP`s "return" jack so I can bypass the ampeg`s preamp and only use the power section. Compared to the ampeg, i`ve noticed that now the overall volume and EQ seem to be more sensitive to changes, and sounds really good at low volume... really useful for practising at night if I dont want to use headphones and don`t want to lose tone.

Hope this thread come to live again, i`d love to read some comments about how you are dealing with your mods.

 

[VeskuFIN]

In the specifications of the Speaker it suggests that with a vented box enclosure I should have 19 liters of internal volume (which is a bit less of the 0.7 cubic feet this amp has) and a port/duct of 3" in diameter and 2" long. As the Ampeg has an 3"x3" I am thinking on trimming an inch... what do you think about it?
As i live in Argentina and imported products are banned, I cannot purchase flared ports, so im staying with the stock one, trimmed.

For the stock speaker, I recall that the reflex tube's length was roughly correct. It was tuned around 71 Hz, which is fine for stock speaker.

It's easy to cut it if needed with sharp knife or something. It's made of cardboard though, so it's a bit difficult to do it neatly. The inner end of the tube in my amp was uneven and partly collapsed. I bought some plastic drainpipe from the local dealer for 3 euros, and used it as reflex tube by sawing it to appropriate lenght. Used short part of the original tube as a gasket for the new one, because it happened to fit inside the original tube just perfectly.

I wrote an article here:[Invalid or Expired Link Removed]

By the way, adding filter caps didn't eliminate the odd buzzing problem. It is just the same buzzing that jledouxart described. I first thought that it was gone, but realized later that it's still there. I guess I will replace components one by one, until I find the reason for this damn buzzing. However, it is highly recommended to do the filter caps mod. It will have even bigger impact to the amp's performance than swapping the speaker.

 

[VeskuFIN]

Actually, I think I'll write an article about the filter cap mod with excact instructions and pictures. I noticed that my previous description is too inaccurate for those who are not familiar with electronics.

 

[Hi-End Basses]

Well then, I guess I'll just have to sacrafice collectability for an amp that meets my needs.

I have both BA108 and BA110 as well, but the BA110 doesn't fit in the trunk of my car.

What kind of Smart car do you drive?

S

It must be a very small car!

 

[VeskuFIN]

So far these things are confirmed not to cause the buzzing:
- Cabinet rattle
- Speaker itself
- Insufficient filter caps
- Opamp

As it seems that this is a quite common problem, I contacted Ampeg technical support, and asked them if they've addressed and fixed this in V2 but:

"This is not an epidemic issue, so nothing would have needed to be addressed with the V2. My suggestion would be to either have your amps checked out by a repair technician. "

So, thanks for nothing I would say.

 

[NanoGR]

Actually, I think I'll write an article about the filter cap mod with excact instructions and pictures. I noticed that my previous description is too inaccurate for those who are not familiar with electronics.

Thanks a lot for the quick answer! I thought no one would ever reply...

So, I tried the amp today, after glueing and putting some new tight gaskets to the speaker to tighten it up, and all of the sudden all the rattlings were gone. All the stuff in my livingroom shaked though... haha! Anyway, I trimmed the port to the JBL specifications and it seems to ended up tuned a bit high and the port chuffes when playing a D string open. Will buy some pipes as you say and lengthen it a bit and see what happens.

As for the filter cap mod, I`d love to have some instructions as I am not really experienced in electronics and don`t want to blow anything... I`m good at soldering though, so with a good hint will be enough. A friend is helping me too so we have two brains and four hands.

 

[Ben B]

I'm glad to see this thread still alive. Early on in this thread, I posted about my Fender Rumble 15. I did a speaker swap with an Eminence Alpha 8. The Fender started to fail and I didn't want to repair it. I replaced it with an BA-108 V2.

I pulled the Alpha 8 out of the Fender and put it in the Ampeg. I wasn't worried that the BA-108 V2 came with a 4 ohm speaker and the Alpha 8 was 8 ohm--I figured it was a more efficient speaker, so, it would go louder. I was right. The amp went much louder before getting distortion. I then added two 2 inch by 2.25 inch long ports and lined the cabinet. Now it goes deeper as well as louder. It's an impressive little amp for the price. I just wish the cabinet was lightweight plywood instead of MDF, but I understand that Ampeg has to use MDF to make their price point.