DGBass

Thought i'd just post a note to say what transpired with my porthole cab refurbishment. It's taken a while to get everything together and as always testing and making adjustments does involve time when its something non standard. Unfortunately the original 38 year old Fane Sovereign Pro 15-250 driver failed after three rehearshals after developing some voice call rub. Spending a decade in a damp garage and then a few weeks in a warm dry indoors environment seemed to have distorted the cone. However, I had a spare woofer boxed in the cupboard as all well prepared bass players have. It now has the spare 8 ohm Faital Pro driver I bought a few years ago. Some fine tuning with my internal volume calculations brought the tuning frequency as near as can be to about 50Hz which seems to be fairly standard for a mid nineteen eighties cab. Lined with 3/4 inch dacron the cab sounds well damped and the big 15 PR 400 doesn't seem to complain at all no matter what I throw at it. Everything sounds crisp and clear to me. Pick playing especially sounds good and thats not usually my bag. The original TE grille was re-mounted with new rubber pads, and a new speaker jack plate fitted with combi speakons. It's approx 19kg all in and lighter and smaller than my MM cab so its very likely to get a bit of use soon. It's not perfect but the cab was donated free and the spare driver was already paid for. Mostly it was just a little cosmetics cost required to get it to where it is. It's good enough to gig now and only needed a minimal amount of science to understand the cab design. For the most part it was finalized with some old fashioned listening time 🙂

Band not gigging at present due to band member health issues and rehearshals are also infrequent. The opportunity for some rehearshal studio shake down time was too good to pass up today. If I was gigging this weekend, I'd be using this lot of bass noise making stuff.

Bought a Boss synth pedal from Gaz and has been a perfect fuss-free purchase. Friendly comms, quick delivery and well packaged item. Many thanks Gaz, you are a top basschatter.

The first bass is reminiscent of KAY branded medium scale basses which were fairly common in the 1970s and even into the early 1980s. There used to be a pawn shop /music store I recall in the east end of Glasgow in the late 70s called Golumb's. That was when you could actually still come across a genuine pawn shop bargain. They sold all manner of new Kay design guitars and basses alongside pawned p-basses. jazz basses and even gibson RD basses and the like etc. The Kay stuff always seemd to have quite thin bodies and seemed flimsy to me but lots of people used them as they were inexpensive, cheerful, and actually quite playable. No idea what that second bass is.

Most folks of a certain age have probably played through a Peavey at some point in their gigging career. They were prolific from the late seventies, eighties and a part of the nineties and dependable gigging amps imho. My only 2 ohm load version was a MK VIII bass head. I ran that into a 4 ohm 115BW and a 4 ohm TVX 410. 600 watts it said on the rear panel at 2 ohms and it did feel alot when wound up. Never had a single bit of trouble with it. I did own a MK III 150 watt head until recently and that too was completely trouble free ownership although i'm sure that was a minimum 4 ohm load. Mostly the bigger wattage heads from around 250 watts up ( BH400 power module) seem to be labelled as being able to run at 2 ohms.

These might help. EV mention a specific response for a 3.2cu ft TL606 enclosure and that can't be far of the mark if i recall the size of my old Mesa/Boogie Diesel 1x15 cab. The power rating on that cab was 400watts @ 8 ohms for what that is worth. There may have been a 200 watt version as well.

There are always options. Just saying I can't find any commercially available rack case that weighs 2.5kg. Even with a 5kg rack case, you would in theory only be adding an extra 2.5kg over your ideal 2.5kg CF case. Thats about the combined weight of the front and back lids on a typical 3U or 4U case so if you were prepared to use the rack without the lids that would get you to within 0.5kg of your target weight. I've seen plenty players over the years use open rack cases with no front or back as its more about the convenience of having the kit in one box, in effect just like an amp sleeve. The kit still has some protection from the main part of the case and theres some weight saving by not having the front and rear lids on it. A comercially available nylon padded case might also get you down to about 4kg which would be 1.5kg over your target 2.5 kg weight. I've always found the best approach to having a lightweight rack system is to start with the rack of choice and then fill it with lightweight stuff.

I would think a 12kg SVT 3Pro would negate any real notion of saving substantial weight once installed in any rack case. A couple of kg won't feel a lot but I suspect the dent in your wallet for a full 3U carbon fibre case if there is such a thing that weighs only 2.5kg would be a lot more painful to carry! Actually, an SVT7 pro only weighs around 7kg, thats a 5kg lighter option if fitted in a decent polycarbonate or Aluminium case 🙂 I did have a look for CF cases ( ECS make them as well as composite versions), and also injection moulded types as alternatives but couldn't find off the shelf CF stuff and the injection molded cases were around twice the weight of conventional cases. ECS make a 4U composite case but it weighs 21kg. I am super interested to see if anyone on BC can find what you are looking for. I suspect though it doesnt exist (yet!) and if it does, it will be eyewateringly expensive in comparison with AL or Poly cases.

Been using one of these for a good few years now and find it works with just about any amp I care to use. It works especially well where thers a tube in the amplifiers pre-amp. I initially bought it to use as a limiter but soon realised it can also do a very subtle compression that keeps the signal tight and under control without killing natural sustain. The enhance knob can also add a subtle crispness to the top end without it getting fizzy. Great all round pedal and I always have it last in the chain before the amp.

I probably ( definitely ) don't need another ABM but this one caught my eye recently. Apart from the current 750 EVO 5, i've never seen a Blackface ABM500 head before. I do remember years ago seeing a Whiteface Special Edition version but not the darker variant. Its basically EV0 III internal gubbins from what I can see and has a normal ice blue rear end. S/N 3585. Had had a hard life when I got it. It's been fully restored and all working well and sounding just like umm...an ABM. I never thought i'd like the dark finish but its grown on me. Curious if any BC users have a Blackface or Whiteface special edition ABM, are still using it and can share any history of these editions?

I will say diagnosing an issue without actually having the amp on a bench is always tricky. Expect the unexpected, especially if the amp is still working after a fashion. It will though be interesting to see if you can spot anything from a photo. There are a lot of high voltage caps in the SVT7 pro so be very careful when the lid is off not to touch or short anything and make sure it isn't plugged in 😬

Agreed, and sure I mentioned that when reffering to the driver chip circuit caps of potentially the value on the burnt remains of the component in the picture. C25 on the power board looks the most likely possibility to me, its a de-coupling cap and sits on its own between two parts of the amplifier. If it blew i'm sure the amp would still work as the driver circuits each have independent voltage feeds. As the cap would be gone, any harmful voltage wouldn't get anywhere else, you would more than likely just loose the de-coupling effect which might increase background noise rather than total amp failure. I'm pretty sure its not the pre-amp as I don't see any component value with a 47 or 25 on it. It's forum diagnosis at its best or worst if you like. The only way to know for sure would be to pop the hood and start taking high res photos of the SVT7 Pro mainboard. I don't recall coming across an amp guts reference library thread here on BC? Happy to attach schematics if you fancy a look at them🙂

Just for info, I had a look at the SVT7 Pro SMPS power board schematic and there are a few possibilities on it for similar spec caps as well. It's the age old issue of trying to figure out whats wrong from a forum post and the SVT7 Pro is also fairly complex bit of kit anyway. A Tech and some bench time are probably the best option when it comes down to it if you have an amp problem. I wouldn't write off class D, I've used Markbass kit as an example regularly and it was very impressive and reliable in my experience.

It's definitely the remnant of an electrolytic capacitor. Difficult to tell the rating but I can make out a 47uf or maybe 0.47uf rating and maybe 25V or 250V voltage rating. There isn't anything anywhere near those ratings on the pre-amp schematic. On the power amp schematic there are a few possibilities C141 0.47 250V C173 0.47 250V C25 47uf 25V I'm not familiar enough with these amps ( class D design possibly as it uses a pair of IRS209555 driver chips ). Whatever happened to the suspect cap, it must have let go in a spectactular fashion as the pressure cap is completely gone as are the leads that connected it to the board. Odds on if it came from your amp, there will be a couple of stubby wires protruding from the board somewhere. C25 looks the most likely candidate as the other caps C141 and C173 are integral to the driver chip circuits and i'm guessing the amp might not work at all if those failed. Class D amps by design require noise filtering because of the high frequencys involved in their workings. I know its probably not helpful but if I was to venture into non full blown tube SVT territory, I'd plump for the tube pre-amp class A/B power amp SVT3 Pro and give the class D SVT7 Pro a wide berth. I'm sure the SVT7 Pro is a capable enough amp, and a good replacement might be just what you are after. If its going back to where it came from at least you'll have an option to think about a replacement amp whether thats Ampeg or something else.

Sometimes the rig of choice for the weekend is the only rig available. An impromptu jam/gig at a friends party/barbecue saturday evening happened at his garden studio for the barbecue attendees. I once owned the ABM400 410H he now uses in the studio. It's changed hands over the last few years amongst the local bass playing population and has found its forte as a studio amp that doesn't get carted around anymore. Probably a good thing as it weighs about the same as a small elephant. Forgot how good the old school mosfet powered Ashdown ABM400's sound. Silky smooth tones with a hint of sparkle from the tube pre-amp and a very useable sub octaver.

Wise words from the BC community and would be first thing I would check. They don't always have a big obvious EV label on the back but should have a stamp of some type, often with a traceable OEM code. Like the TL606 cabs, the speaker chassis is fairly heavyweight. I played one of these for some years and it was the first decent cab I used my ABM's with. Must admit it never lacked delivering low end in anyway, if anything I had to moderate the amount of bottom end. It was one of the few cabs I've used that never complained or struggled with lots of bass. It was also one of the cabs I wished i'd never sold 😐

The mosfet version power boards in these early ABM's are prone to failure if the caps are past sell by date which is usually around 20-25 years with regular use. There's usually a bit of smoke and charring if they do and for some peculiar reason it's the mosfets on the left side( from front) that usually fail. As the good folks at Ashdown will tell you, it's best to replace all six mosfets if you have a failure as well as the four coupling caps. It might be easier asking if they would sell you a current pre-built APC033 (issue 4) modern Bi Polar power board as a drop in replacement. It may be cheaper than getting a tech to rebuild the original board for you. Of course thats if the power board is the issue 🤔 Had the caps fail on one I owned and elected to rebuild. It was messy but worked out in the end. scorched board caused by two shorted caps finished board

Love the groove, especially the second clip 😎 Not my pref in colour for an instrument but your bass sounds um... just like a Jazz should!

plastic vintage inspired knobs on a £4200 bass? Oh dear. My only ever pre-ernie ball bass cost me £295 new from the local corner music store back in the early eighties. That was only because the shop couldn't sell it at the retail price, an extortionate £429 😬 How things have changed. At least my late seventies bass had proper chrome knurled knobs. I'd never buy one new nowadays, even though they are without a doubt classics in their time and have that sound.

I've heard it said many a time that hiss is better than hum when it comes to bass amps. Some amps though are noiser than others, even from new. I recently had a chance to play through an old Ampeg B2-RE 450 watt amp with 1x15 and 4x10 Hartke cabs, both with horns and both horns were on at the time. The Ampeg was so quiet at idle I thought at first it wasn't plugged in to the cabs. There was virtually no hiss at all even at decent volume levels and controls set flat. I also have a couple of GK amps and even with the volume up high, they barely hiss at all through tweeter cabs. Pre-amps with a tube in them can pick up a bit of noise, especially if the tube isn't at its best. If you have the option try several amp heads with your cab to compare. It might just be a particular combination of amp/cab and not anything really wrong with either.

I'm curious as to why you arranged the amp to sit on its end with your BC110T? Is there a marked difference to the sound if the cab is laid on its side to accomodate the amp on top?🤔 Or was it just to avoid the dreaded bass overhang in the upright position? 😉

Its quite interesting to hear everyones take on the One10 and whether one can cut it or two is the best option. I was in a similar situation when I bought my first One10 as the OP. For home rehearsal its a great option. However even at light band rehersals I found a single One10 never quite lived up to BF's claim for me at least. My main cab at the time was a decent 1x15 ( a Mesa Diesel TL606 EV 1x15 cab.) Using the One10 as a stage monitor pointing directly at me and used in conjuction with the Mesa it couldn't be heard at all over the output from the Mesa. I added a second One 10 eventually thinking that would be a better match and it did improve the situation but both cabs together still couldn't match the vast low end output from a single Mesa 1x15 cab. In hindsight, I should have ordered one BF 2x10 cab from the outset as it would have been eminently more useable as a home use / light rehersal small gig cab and less expensive than a pair of One10's and only one cab to move around. The only benefit at the end of day with the One10 for me was the small lightweight formfactor and its lovely warm tone at low to med volumes as long as low frequencies were backed off on the EQ. If the OP is used to a 6x10, then a BF 2x10 would probably be a more useable option than going down the smaller two cab route.

It's an earlier MKII GP11 in the FB ad so above schematics wouldn't apply. These also have the ECI wiring which is a heap of trouble if you can't test its working before buying it. It will likely have come from an early AH150 or AH250. The ad picture looks like a rather poor condition and well used unit with missing knob caps and a non standard input jack. So its had work before and i would guess would need a fair bit of work to bring it up to standard. You could easily spend another £50 getting it working and at the end of the day you would struggle to ever recoup that. £25 spares/repairs is probably more realistic unless the seller has the old blown power amp unit he could throw in. The power amps are generally bullet proof and very easy to fix if they do stop working. The pre-amps are a bit more complicated. The trouble with starting a project like this these days is that folks are stripping down old trace amps because they realise they can make a lot more money selling parts than a whole unit for spares or repair. Parts are sold as no return/untested so if you do by a dud part theres little comeback. Whole working TE amps of this era in good nick and reasonably original condition are becoming very scarce nowadays and that will probably encourage the parts strippers to break up anthing they can get their hands on. Saying that, its a good enthusiast project and with a bit of work, a suitable power supply and a nice slim 2U rack case it would make a great wee project and a brilliant pre-amp once working. These old GP11 pre-amps have a great silky smooth tone. I can vouch for that as I have one in perfect working order and very good original condition 😁

The pin assigment can vary on TE pre-amp sections. Seeing the front panel might be helpul to identify your version. The schematic applies to MKV GP11's. MK II GP 11's also had extra wiring for the ECI function ( earth continuity indicator ).The MKV GP11's were used on a multitude of different amps but mostly AH150 heads and AH250 heads. Both had different feed voltages from the power section tranformers. Basically they use a half wave rail voltage from the main power supply, a big step down resistor on the pre-amp main board, a voltage regulator and zener diode run the pre-amp on roughly 30-35V dc. On my AH250 the feed voltage to the GP11 MK V via the 6 pin connector is 65V dc. On my AH150 GP11 MKII it is actually higher at 71V but thats because it has a rare 50V transformer and not the usual 40V one. The step down resistors are the critical part as they drop enough voltage so as not the smoke the pre-amp🥵 Some of these pre-amp sections aren't really interchageable between different models even though they have the same 6 pin multi plug socket. Might or might not work and you might or might not get smoke! I've just rebuilt one recently ( a MKV GP11) that had been through the wars. The multi plug was missing, long gone on a dodgy amp service years ago and the cables were hard soldered onto the pins. See pic, the red and black are the power supply, the blue is tip/signal out and the signal out screen is on pin 6. A 2 core screen cable out to a power amp and a pos and neg from a supply voltage ( anything around 60v dc would likely do) and would most likely get your pre-amp working assuming its in good order.