I recently finished what I think to be a worthwhile cab modification.
While patrolling the local garage sale scene with my toddler son, wading through books, old video games and over-sized stuffed animals, I stumbled across a speaker cab bearing the familiar Peavey silver-on-black grill. Externally the cab looked to be in pretty good condition. It was reminiscent of my old, BIG, PV 215 cabs from the 80s & early 90s, so I decided to inquire. The rear label claimed 210 column. Hey, I could use a small practice cab!
The original price was $40. I pulled the grill to see if the cones were ripped and found a mismatch of non-standard drivers. This provided a great source of haggling, and we ended at the princely sum of $6.00. Cash.
I figured the cab to be about 2 ft3. I had a deltalite II 2510 collecting dust, and from memory thought this could make for an interesting retrofit.
Goal-
A good sounding, full range practice cab on the cheap. Use what is available around the house, and spend the least amount of time possible modding the cab.
My $6.00 garage sale find- the PV 210 Column PA cab.
Heres a peek at what I found under the grill.
Upon pulling the drivers I found some real old vintage stuff! A 9 Zenith with a ripped cone and a 12 Wilder wired in parallel. I think the Wilder will be shelved for use in a future project. (With one of those little epi valve juniors I bet it'd... hmmm)
Assessing the baffle Chip board. Yuk. I could do without the fiberglass as well. Buh-bye.
The baffle and rear are 3/4 chipboard or pressboard of very dubious structural integrity. The baffle was replaced with spare 1/2 Arouco plywood left over from a bookshelf/cabinet job I just finished up. (Incidentally, this stuff is very lightweight and, depending upon the batch you grab, is of pretty nice quality. Be selective. I pulled a few out of the pallet that showed voids and many un-plugged knots.)
Notice the tonewood pine forming the sides of the cab? Hmmm was PV the predecessor of Ear Candy cabs!?
Not wanting to endeavor into a new Tolex job I decided to leave the sides and the back pressboard in place and just brace it a bit. Afterall, this was a cab mod, not a rebuild!
I left approximately 1/2 of an inch of the original baffle around the perimeter of the cab and glued plywood strips to this. Not only was this very fast and easy to do, I decided this would serve as a stable platform onto which to secure the new baffle. The 1/2 ply would surely offer better screw holding than the chipboard.
The 1/4 jack wasnt sealed. Since this was a sealed cab, I imagine this caused some issues with hissing or chuffing. Or not. Regardless, it was fortified with some PL and then sealed up using a spray can lid glued in place.
New accoutrements-
A new baffle with appropriate porting, some PL glue on the seams and over the knot holes and random emergent nails, as well as some new stuffing thanks to 2 old pillows and egg-crate packaging I snagged out of the trash at work.
I also added a 1/2" ply skeletonized shelf brace bisecting the cab. An old purple Yoga matt sliced into thin sections served as the seal onto which the baffle would rest.
I mounted the driver using 4 hurricane nuts and 4 sheetrock screws. I predict that I will regret this in the future. Brackets would have been better, but I have none.
The hole was cut using a dremel tool freehand. As such, I unfortunately veered on the side of excess and cut the hole a tad large. You can see how close the hurricane T-nuts are to the edge of the hole. The driver went in square, and is cinched down tight, but in time I bet itll be a weak link. ** future note- use a circle jig, preferably with a router. **
So, how to tune the cab?
These calcualtiosn came before the cab mod, but I will discuss them here. The interior dimensions of the cab, accounting for the driver and newly added bracing, came out to 1.75 ft3. Actually, It is probably a little more than that, but I erred on the side of caution in my calculations of driver volume. Net internal is probably 1.75 1.78. Short of filling it with sand or water, thats the best I could do, and probebly plenty good enough.
I used the now famous bgavin spreadsheet to find out if my DL2510 would work in this space sbb4 is in about 1.5 ft3 tuned to 53 hz , optimal flat is about 2 ft3 tuned to slightly less than this. QB3 is between the 2. Using my actual volume tuned to 50 hz should put me in between qb3 and sbb4 alignment. Fully acceptable and probably "more appropriate than many commercially available cabs. Shouldnt be muddy at all, and the f3 should be in the neighborhood of 55 hz fif I recall correctly.
What to do for mids or tweets?
The 2510 has a rep for having a nice midrange for bass guitar, so I decided a 2 way cab would be acceptable. However, Even an inexpensive crossover would be more than the cab cost me, so that was out of the question. That left me with piezo tweets as the only option. Fortunately I have a bunch of them sitting around, and at a couple bucks each the price is right.
I planned for three 1016 piezos wired in series, but I later decided to only use 2 in the event I needed a spare later. A mistake I made was placing the 2 keepers at the top of the cab instead of closer to the woofer. I decided this wasnt a big enough issue to lose sleep over or go back and redo the baffle.
Port construction
I was able to save on parts by using a plywood port. The only PVC I had was 4, and this would eat up too much cab volume. Plus, slot ports have the benefit of acting as bracing.
I used this site Invalid Link Removed and some advice from TB members to determine the dimensions of my port.
In a slot port the cab walls act to extend the effective length of the port. This, imo, lowers ones ability to rely solely on theoretical calculations. Exact dimensions matter, and I imagine the presence of or lack of routed edges would as well. Since my port was a square slot port as opposed to a round one , and since the mouth of the port would be physically close to the shelf brace inside, I thought it prudent to check my cab tuning electrically. Would the shelf brace act as a cab wall?
Confirming & adjusting cab tuning-
A tone generator provided the signal sweeping. I ran it into my GB440 which in turn powered the cab. I can only hope that the tone generator was calibrated. I had to assume so.
As described in Dickasons book and elsewhere on the net (again, thanks bgavin for a post from years ago) I placed the equivalent of a 100 ohm resistor (20 watt) in series with my driver. I then connected my analogue multimeter in parallel across the driver leads and found- nothing. I heard noise form the speaker, so there MUST be a voltage drop across the driver! Something else was wrong.
I suspected the minimum voltage range of my multimeter was the issue, so out came the digital multimeter. Voltages were typically below (and near) 1 volt, so the lower millivolt range of the digital multimeter was more appropriate.
I swept the freq from 25 to 100hz several times and noted minimum voltages falling between 51 and 54 hz with gradual peaks on either side These results were repeatable over various volume levels and several trials. . Voltage dropped off below 30 hz rapidly. I didnt bother sweeping above 100 hz . Frankly, considering all of the variables, I was shocked that I was within acceptable range without any mods to the port. I thought the proximity of the skeltonized shelf brace to the slot port would dramatically alter the cab tuning. Assuming it would, I left the port length a hair short (easier to glue on strips than cut and make all than sawdust in my stuffing!) and pretty much got lucky. I left well enough alone.
The setup can be seen below.
External
The original grill was in good condition so I decided to re-use it. The Peavey emblem was cracked up pretty good, so it was tossed. We had some ebony paint left over from a bedroom furniture project, so I applied a few coats to the baffle so that the bare wood wouldnt show through the black grill-cloth.
The little feet you see on top of the cab were only placed there to support my otherwise footless gb440. (incidentally, if anyone has 4 screws that fit the gb/amp/tfb feet I'd appprecaite a PM). You can also see some stuffing through the port. I have since added some old nylon window screen inside the cab to prevent fluff from leaving via the port or critters from entering the cab.
A strap handle from parts express (salvaged from my len Moskoqwitz cab project) was added, as were new plastic cab corners that were salvaged from, well, I am not sure where. I think an old hartke.
Here she is, all dolled up
There is, however, one problem in using the old grill. I will address that in the future. For now I am using it sans grill.
Money money money money moneeey!
Total cost, even if you include the spare stuff I had laying around, comes in at well under 100 bucks. The driver is an OEM version of the Eminence DL2 2510. ON ebay last year it was $55 or 60. The tweets were about 5 bucks, the strap maybe 3. Glue & wood was leftover from my bookshelves, but couldnt have cost more than $5 bucks regardless. The cab corners were recycled, but would have cost maybe another 4 bucks. Even if you include the cost of paint for the baffle and the old pillow I am still under $80.
Time spent...
The nice part is that, since I wasnt worried about screwing up a complete new build and that since I was able to break this project down into 15 or 20 minute jobs, I was able to fit this cab-mod into my highly fractionated schedule. All told it was perhaps seven or eight 15-20 minute sections of time. Perfect! All told, just over 2 hours.
The proof is in the puddin
So, how does it sound? The first thing I noticed was how subtle yet nice the tweeters sound. My bass has a lovely tone when run direct through a PA, and the subtle crispness the 2 piezos add is appreciated. I have not really been a tweeter guy, so I was worried they would sound overpowering. Harsh and brittle are terms often used to describe inexpensive tweeters. Not so here. I wired them series to try to minimize their sensitivity, and perhaps this helped.
Most importantly I found no buzzing, rumbling, chuffing, scraping, chaffing, wheezing, chugging, or other sundry unwanted sounds. The cab is physically tight.
The cab overall sounds amazingly well balanced. I typically cut 15db at 30 hz to protect my speaker cabs from damage. I wont try to imply that this cab has earth shattering lows. However, it does have a very even PERCEIVED response across the useable spectrum at very loud solo practice levels. It has plenty from 60 hz through the useable eq band of my gb440.
What I like so far, and mind you this is only while practicing alone, is that the cab seems to take to EQ quite nicely. It isnt boomy, and anything I dial on my EQ can be noticed. Again, at the moment not being in a band situation, this could be moot. My typical 1 click left on the timber knob yields extremely pleasing tone. I have yet to practice with a band or gig with it.
It is not very loud. I have my amp set at 5 and 5 on the gain/vol knobs, amp set flat, nothing boosted on bass nor on the amp, and the aforementioned one click left on the timber knob. For those of you with a BH420/gb440/TFB420, you know that this is a fairly loud setting going into typical gigable cabs.
By comparison, the volume at these settings is much MUCH less than on my mline wizzy or my EV tl806. Obviously this comparison is 8 vs 4 ohm and the subsequent watage differences, and 10" vs 12 (not to mention 2 of the best speaker cab engineering companies on the planet comapred to , well, me!) but it is the only head to head comparison I can make. I couldnt possibly gig with it in my band, and itll probably be pushed a bit during rehearsals. For sane rehearsal vols, practice, or small or quieter gigs, I think it will excel.
The tone is infinitely more balanced than the uppermid & midrange present (low lacking!) EV, and has FAR more snap in the highs and upper midange definition than the Mline. The mline wizzy has a greater natural low & low-mid voicing, whereas my 110 seems more PA-like. (Is it poor form to imply it is flat? How about FlattER?)
Ironically, the overall weight, with grille on, is exactly the same as my mline wizzy- 34 lbs. Thanks in part to those pine sides i am sure!
Since this cab is tall for its size (26 1/2) and not very deep (under 12) it is a breeze to carry and has a very nice, small-yet-tall form factor.
As an aside, I think the Mline with a switchable row of these exact piezo tweets could be the ultimate in small/loud/light/great bass cabs. Is that blasphemous?!
IN comparing it to a previous & similar DIY project, Len Ms Compact Bass Cab, there is no comparison. While I was dismally disappointed with that outcome, I was pleasantly surprised here.
Overall, very pleased with the outcome of this project, and I encourage others to try your hand at modding old gear on the cheap, especially using the wonderful resources available on this an simialr forums.
IMO the question of what to do with my old blown hartke 210 is answered.
While patrolling the local garage sale scene with my toddler son, wading through books, old video games and over-sized stuffed animals, I stumbled across a speaker cab bearing the familiar Peavey silver-on-black grill. Externally the cab looked to be in pretty good condition. It was reminiscent of my old, BIG, PV 215 cabs from the 80s & early 90s, so I decided to inquire. The rear label claimed 210 column. Hey, I could use a small practice cab!
The original price was $40. I pulled the grill to see if the cones were ripped and found a mismatch of non-standard drivers. This provided a great source of haggling, and we ended at the princely sum of $6.00. Cash.
I figured the cab to be about 2 ft3. I had a deltalite II 2510 collecting dust, and from memory thought this could make for an interesting retrofit.
Goal-
A good sounding, full range practice cab on the cheap. Use what is available around the house, and spend the least amount of time possible modding the cab.
My $6.00 garage sale find- the PV 210 Column PA cab.
Heres a peek at what I found under the grill.
Upon pulling the drivers I found some real old vintage stuff! A 9 Zenith with a ripped cone and a 12 Wilder wired in parallel. I think the Wilder will be shelved for use in a future project. (With one of those little epi valve juniors I bet it'd... hmmm)
Assessing the baffle Chip board. Yuk. I could do without the fiberglass as well. Buh-bye.
The baffle and rear are 3/4 chipboard or pressboard of very dubious structural integrity. The baffle was replaced with spare 1/2 Arouco plywood left over from a bookshelf/cabinet job I just finished up. (Incidentally, this stuff is very lightweight and, depending upon the batch you grab, is of pretty nice quality. Be selective. I pulled a few out of the pallet that showed voids and many un-plugged knots.)
Notice the tonewood pine forming the sides of the cab? Hmmm was PV the predecessor of Ear Candy cabs!?
Not wanting to endeavor into a new Tolex job I decided to leave the sides and the back pressboard in place and just brace it a bit. Afterall, this was a cab mod, not a rebuild!
I left approximately 1/2 of an inch of the original baffle around the perimeter of the cab and glued plywood strips to this. Not only was this very fast and easy to do, I decided this would serve as a stable platform onto which to secure the new baffle. The 1/2 ply would surely offer better screw holding than the chipboard.
The 1/4 jack wasnt sealed. Since this was a sealed cab, I imagine this caused some issues with hissing or chuffing. Or not. Regardless, it was fortified with some PL and then sealed up using a spray can lid glued in place.
New accoutrements-
A new baffle with appropriate porting, some PL glue on the seams and over the knot holes and random emergent nails, as well as some new stuffing thanks to 2 old pillows and egg-crate packaging I snagged out of the trash at work.
I also added a 1/2" ply skeletonized shelf brace bisecting the cab. An old purple Yoga matt sliced into thin sections served as the seal onto which the baffle would rest.
I mounted the driver using 4 hurricane nuts and 4 sheetrock screws. I predict that I will regret this in the future. Brackets would have been better, but I have none.
The hole was cut using a dremel tool freehand. As such, I unfortunately veered on the side of excess and cut the hole a tad large. You can see how close the hurricane T-nuts are to the edge of the hole. The driver went in square, and is cinched down tight, but in time I bet itll be a weak link. ** future note- use a circle jig, preferably with a router. **
So, how to tune the cab?
These calcualtiosn came before the cab mod, but I will discuss them here. The interior dimensions of the cab, accounting for the driver and newly added bracing, came out to 1.75 ft3. Actually, It is probably a little more than that, but I erred on the side of caution in my calculations of driver volume. Net internal is probably 1.75 1.78. Short of filling it with sand or water, thats the best I could do, and probebly plenty good enough.
I used the now famous bgavin spreadsheet to find out if my DL2510 would work in this space sbb4 is in about 1.5 ft3 tuned to 53 hz , optimal flat is about 2 ft3 tuned to slightly less than this. QB3 is between the 2. Using my actual volume tuned to 50 hz should put me in between qb3 and sbb4 alignment. Fully acceptable and probably "more appropriate than many commercially available cabs. Shouldnt be muddy at all, and the f3 should be in the neighborhood of 55 hz fif I recall correctly.
What to do for mids or tweets?
The 2510 has a rep for having a nice midrange for bass guitar, so I decided a 2 way cab would be acceptable. However, Even an inexpensive crossover would be more than the cab cost me, so that was out of the question. That left me with piezo tweets as the only option. Fortunately I have a bunch of them sitting around, and at a couple bucks each the price is right.
I planned for three 1016 piezos wired in series, but I later decided to only use 2 in the event I needed a spare later. A mistake I made was placing the 2 keepers at the top of the cab instead of closer to the woofer. I decided this wasnt a big enough issue to lose sleep over or go back and redo the baffle.
Port construction
I was able to save on parts by using a plywood port. The only PVC I had was 4, and this would eat up too much cab volume. Plus, slot ports have the benefit of acting as bracing.
I used this site Invalid Link Removed and some advice from TB members to determine the dimensions of my port.
In a slot port the cab walls act to extend the effective length of the port. This, imo, lowers ones ability to rely solely on theoretical calculations. Exact dimensions matter, and I imagine the presence of or lack of routed edges would as well. Since my port was a square slot port as opposed to a round one , and since the mouth of the port would be physically close to the shelf brace inside, I thought it prudent to check my cab tuning electrically. Would the shelf brace act as a cab wall?
Confirming & adjusting cab tuning-
A tone generator provided the signal sweeping. I ran it into my GB440 which in turn powered the cab. I can only hope that the tone generator was calibrated. I had to assume so.
As described in Dickasons book and elsewhere on the net (again, thanks bgavin for a post from years ago) I placed the equivalent of a 100 ohm resistor (20 watt) in series with my driver. I then connected my analogue multimeter in parallel across the driver leads and found- nothing. I heard noise form the speaker, so there MUST be a voltage drop across the driver! Something else was wrong.
I suspected the minimum voltage range of my multimeter was the issue, so out came the digital multimeter. Voltages were typically below (and near) 1 volt, so the lower millivolt range of the digital multimeter was more appropriate.
I swept the freq from 25 to 100hz several times and noted minimum voltages falling between 51 and 54 hz with gradual peaks on either side These results were repeatable over various volume levels and several trials. . Voltage dropped off below 30 hz rapidly. I didnt bother sweeping above 100 hz . Frankly, considering all of the variables, I was shocked that I was within acceptable range without any mods to the port. I thought the proximity of the skeltonized shelf brace to the slot port would dramatically alter the cab tuning. Assuming it would, I left the port length a hair short (easier to glue on strips than cut and make all than sawdust in my stuffing!) and pretty much got lucky. I left well enough alone.
The setup can be seen below.
External
The original grill was in good condition so I decided to re-use it. The Peavey emblem was cracked up pretty good, so it was tossed. We had some ebony paint left over from a bedroom furniture project, so I applied a few coats to the baffle so that the bare wood wouldnt show through the black grill-cloth.
The little feet you see on top of the cab were only placed there to support my otherwise footless gb440. (incidentally, if anyone has 4 screws that fit the gb/amp/tfb feet I'd appprecaite a PM). You can also see some stuffing through the port. I have since added some old nylon window screen inside the cab to prevent fluff from leaving via the port or critters from entering the cab.
A strap handle from parts express (salvaged from my len Moskoqwitz cab project) was added, as were new plastic cab corners that were salvaged from, well, I am not sure where. I think an old hartke.
Here she is, all dolled up
There is, however, one problem in using the old grill. I will address that in the future. For now I am using it sans grill.
Money money money money moneeey!
Total cost, even if you include the spare stuff I had laying around, comes in at well under 100 bucks. The driver is an OEM version of the Eminence DL2 2510. ON ebay last year it was $55 or 60. The tweets were about 5 bucks, the strap maybe 3. Glue & wood was leftover from my bookshelves, but couldnt have cost more than $5 bucks regardless. The cab corners were recycled, but would have cost maybe another 4 bucks. Even if you include the cost of paint for the baffle and the old pillow I am still under $80.
Time spent...
The nice part is that, since I wasnt worried about screwing up a complete new build and that since I was able to break this project down into 15 or 20 minute jobs, I was able to fit this cab-mod into my highly fractionated schedule. All told it was perhaps seven or eight 15-20 minute sections of time. Perfect! All told, just over 2 hours.
The proof is in the puddin
So, how does it sound? The first thing I noticed was how subtle yet nice the tweeters sound. My bass has a lovely tone when run direct through a PA, and the subtle crispness the 2 piezos add is appreciated. I have not really been a tweeter guy, so I was worried they would sound overpowering. Harsh and brittle are terms often used to describe inexpensive tweeters. Not so here. I wired them series to try to minimize their sensitivity, and perhaps this helped.
Most importantly I found no buzzing, rumbling, chuffing, scraping, chaffing, wheezing, chugging, or other sundry unwanted sounds. The cab is physically tight.
The cab overall sounds amazingly well balanced. I typically cut 15db at 30 hz to protect my speaker cabs from damage. I wont try to imply that this cab has earth shattering lows. However, it does have a very even PERCEIVED response across the useable spectrum at very loud solo practice levels. It has plenty from 60 hz through the useable eq band of my gb440.
What I like so far, and mind you this is only while practicing alone, is that the cab seems to take to EQ quite nicely. It isnt boomy, and anything I dial on my EQ can be noticed. Again, at the moment not being in a band situation, this could be moot. My typical 1 click left on the timber knob yields extremely pleasing tone. I have yet to practice with a band or gig with it.
It is not very loud. I have my amp set at 5 and 5 on the gain/vol knobs, amp set flat, nothing boosted on bass nor on the amp, and the aforementioned one click left on the timber knob. For those of you with a BH420/gb440/TFB420, you know that this is a fairly loud setting going into typical gigable cabs.
By comparison, the volume at these settings is much MUCH less than on my mline wizzy or my EV tl806. Obviously this comparison is 8 vs 4 ohm and the subsequent watage differences, and 10" vs 12 (not to mention 2 of the best speaker cab engineering companies on the planet comapred to , well, me!) but it is the only head to head comparison I can make. I couldnt possibly gig with it in my band, and itll probably be pushed a bit during rehearsals. For sane rehearsal vols, practice, or small or quieter gigs, I think it will excel.
The tone is infinitely more balanced than the uppermid & midrange present (low lacking!) EV, and has FAR more snap in the highs and upper midange definition than the Mline. The mline wizzy has a greater natural low & low-mid voicing, whereas my 110 seems more PA-like. (Is it poor form to imply it is flat? How about FlattER?)
Ironically, the overall weight, with grille on, is exactly the same as my mline wizzy- 34 lbs. Thanks in part to those pine sides i am sure!
Since this cab is tall for its size (26 1/2) and not very deep (under 12) it is a breeze to carry and has a very nice, small-yet-tall form factor.
As an aside, I think the Mline with a switchable row of these exact piezo tweets could be the ultimate in small/loud/light/great bass cabs. Is that blasphemous?!
IN comparing it to a previous & similar DIY project, Len Ms Compact Bass Cab, there is no comparison. While I was dismally disappointed with that outcome, I was pleasantly surprised here.
Overall, very pleased with the outcome of this project, and I encourage others to try your hand at modding old gear on the cheap, especially using the wonderful resources available on this an simialr forums.
IMO the question of what to do with my old blown hartke 210 is answered.
