custom designer / builders - common problem

[lexington125]

I’m looking for a designer / builder to build a tube bass amp head powered by 4ea KT88s and with an extremely minimal feature set, but when I have preliminary discussions with most “custom builders” their reply is invariably some version of:

“well, we can take my standard model XYZ and just redesign all the sections that are different –

• We’ll need to redesign the EQ section (additional $ to not have something)
• We’ll need to redesign the preamp section (additional $ to not have something)
• We’ll need to redesign xxx and yyy and zzz and each will cost money to not include them in your amp.”

I fully understand that we all need to be paid for our work. But from the client’s perspective, should a customer have to pay extra to not purchase something? Does anyone design (and price) an amp as if they were starting from scratch, and only charge you for things you are receiving?

Are there any real custom builders who truly start from a clean sheet and don’t charge to remove features? Or am I just not understanding something?

[J M Fahey]

I’m looking for a designer / builder to build a tube bass amp head powered by 4ea KT88s and with an extremely minimal feature set, but when I have preliminary discussions with most “custom builders” their reply is invariably some version of:

“well, we can take my standard model XYZ and just redesign all the sections that are different –

• We’ll need to redesign the EQ section (additional $ to not have something)
• We’ll need to redesign the preamp section (additional $ to not have something)
• We’ll need to redesign xxx and yyy and zzz and each will cost money to not include them in your amp.”

I fully understand that we all need to be paid for our work. But from the client’s perspective, should a customer have to pay extra to not purchase something? Does anyone design (and price) an amp as if they were starting from scratch, and only charge you for things you are receiving?

Are there any real custom builders who truly start from a clean sheet and don’t charge to remove features? Or am I just not understanding something?

I guess you are under the wrong impression that if a product is made a certain way, "pulling something will make it cost less".

Production does not work that way.

Perhaps you think that if parts cost , say, U$1000 and the maker wants U$1000 for his job, the amp should cost U$2000.

Now if it uses U$900 in parts instead because, say, you asked for "a Twin Reverb without the reverb" it should cost U$900 + 1000 = U$1900 ?
Even worse, since the builder "worked less" , he should charge less for his work, say, U$900 so total amount for that stripped Twin should be U$1800?

Fact is, yes, he will save the reverb tank cost, 2 tubes, 2 sockets, a pot and a few parts , BUT , and that's a big BUT, he'll need:

a) a new custom chassis cut, punched, bent, soldered, plated and shipped.
This alone adds some U$500 to the cost ... that IF some metal shop is interested in making "just one".
Usual minimum order is "100 of anything" or U$5000 to 10000 ... who will pay for it?
You, of course.

b) a new front panel cut, punched, plated/painted, a new silkscreen designed and burnt, silkscreen applied , etc.
Again, minimum order would be 100 front panels for anything from U$2000 to 5000.
Which you will have to pay, of course.

So far, we're talking about an already existing product, already in production, of which you want to pull something.

If you want a new amp, based on some previous product, such as a custom 4 x KT88 amp. , you need to find somebody who already is making one , so he already has chassis, panels, boards, transformers , cabinet, etc. in stock so to make a different, simpler model might "only" need new chassis and panel.

If you want a "white sheet of paper" new design, from scratch, be ready to pay for development cost, starting with U$50000 or more ... would't be surprised at U$100000.

That said by somebody who custom designs and builds from scratch, including in-house making of chassis, panels, transformers, speakers, boards, cabinets and everything else needed, except the purely "electronics" parts (resistors - capacitors - tubes - sockets - jacks - pots - etc.) which are the cheapest part, and can be bought over the counter.

Or to put it another way: the "electronics" parts are the cheapest part of total cost, usually 10 to 20% , all the rest is machinery and equipment investment, accumulated knowledge, which besides the purely Technical side includes getting suppliers , (that they are reliable costs more), lots of time (years), renting/buying a place to work, getting proper licenses, paying taxes, etc. etc. etc.

That's why buying is usually far cheaper than custom making, even self making.

Why don't you design and build one yourself?

You will save the U$1000 the builder will want.

You will have to front all other expenses, and, much worse, the time.

Just to put things in a real perspective

PS: please tell us what do you want in your design, so we have a better idea of what we are talking about

[lexington125]

Thanks for the detailed reply. A few comments:

1. in response to your post, I do understand your points; I guess my confusion comes from only contacting guys who advertise themselves as "custom designer/builders" who offer to design/build your "dream amp" but their response to my request always sounds more like "tell us what you want and we will figure out how to make our standard product look something like what you want."

2. in response to your suggestion that I tell everyone what I am looking for....here goes:

• overall - tube bass amp head
• 4ea KT88 power tubes, preamp tubes as necessary
• power and output transformers sized to work well at bass frequencies
• hand wired on turret or tag board (true PtP is too messy for my obsessive side)
• open to discussion re: 'ultra linear' design

• front panel
• power (on/off) and standby switches
• single input (I only play passive old Fender basses)
• single channel - I'll never understand why so many bass amps have two channels worth of knobs
• single volume control - no master or multiple gain stages
• very basic EQ - passive bass & treble controls - NOTHING else
• NO "bright", "presence" or "deep" switches
• nothing else (no FX loop, tuner outputs, etc.)

• rear panel
• standard IEC power cable connector
• fuses (as necessary)
• speakon connectors for 4 ohm and 8 ohm (or selector switch, whichever is easier to implement)
• (2 ohm would be nice, if there is an approprate output transformer that offers it)
• NOTHING ELSE

that's about it, a tube bass amp (150 watts +/-) with a single volume control and the most minimal EQ that still gives some basic control. I own a 1965 Ampeg SB-12 portaflex and I'm aiming for an amp head with the features offered by that amp, only a lot more power. Having an amp built for me is a once in a lifetime deal, so I'm making NO allowances for re-sale value. Also, re: the power output - some companies claim well over 200 watts from a quad of KT88s (Mesa and others). I'm not looking for the most power possible from this configuration - just enough to keep up with a traditional blues band (50s Chicago / Chess type) when we play on larger stages.

Oh, and while some third world parts may be unavoidable, my goal is an amp designed and built by people earning live-able wages in a country with full worker rights / protections

thanks

[g1]

down & dirty more dead than alive?

[tedmich]

John Chambers at Champ Electronics in Nottingham England could do this easily, it will NOT be cheap as he winds all of his own transformers and is a bit of a legend
Champ Electronics - Vintage Amp Repairs

he might even build you a 500w 2 x 813 tube amp, and he's capable of getting 200w rms out of 4 (good!) EL34s

I for one don't quite understand anyone (not playing stadiums) who needs 200w...

[Leo_Gnardo]

I built an amp very close to what you describe in 1997. At current prices, I'd have to charge $2000 to make another unless I wanted to work for free. The amp's owner uses it much the same as you plan to use yours.

About power figures. Most MI manufacturers publish a wattage, but don't tell you at what % distortion they make their measurements. For hi fi gear, that would be scandalous, most hi fi being measured at some fraction of a percent distortion. Figure on a good 20% distortion for music gear. Mesa's 200W amp becomes a 140W amp measured "at clip", not with a good square wave going.

There's also something to be said for NOT forcing the maximum wattage out of tubes. Amps running with lower B+ voltage say 400-500 V, tend to sound a bit more relaxed than their "high-tension" competition. So you're right to use your ears, go for a good tone and don't worry about squeezing out every theoretical watt.

With a set of used JJ KT88's and a B+ around 525V, the one I built measures 120W at clip. What you're aiming for is certainly within reason. Now who's going to build it at a reasonable price.

[John_H]

...Or am I just not understanding something?

[gui_tarzan]

John Chambers at Champ Electronics in Nottingham England could do this easily, it will NOT be cheap as he winds all of his own transformers and is a bit of a legend
Champ Electronics - Vintage Amp Repairs

he might even build you a 500w 2 x 813 tube amp, and he's capable of getting 200w rms out of 4 (good!) EL34s

I for one don't quite understand anyone (not playing stadiums) who needs 200w...

My Ampeg SVT3 is rated at 200w @ 8 ohms, 350w @ 4 ohms and I can't turn it up much past halfway in most of the venues we play at. The only time I use two speakers (to get 4 ohms and more on-stage sound coverage) is at outdoor events and my line-out is run through the PA anyway. When I played at big outdoor events in the past the sound companies always used a DI to put my bass directly through the PA and I only had my amp and one speaker for the drummer and I to hear it.

I can see why someone would want at least 100w, if you have to turn it up all the way to hear over the drummer and/or guitars you'll likely have distortion and that's usually not good.

[J M Fahey]

I guess my confusion comes from only contacting guys who advertise themselves as "custom designer/builders" who offer to design/build your "dream amp"

A real designer is very hard to find.
I mean somebody who can start with a clean sheet of paper, some datasheets and a calculator.
In the old glory days, a slide rule.
In the MI field, most (99%) designers are really tweakers of old classic existing designs.
Many sound very good, a few even better than the originals ... but in my book that's not truly designing.
"Dream amp" is standard Marketing, doesn't mean anything special.

but their response to my request always sounds more like "tell us what you want and we will figure out how to make our standard product look something like what you want."

Reasonable because you aren't paying tens of thousands for a full design.

2. in response to your suggestion that I tell everyone what I am looking for....here goes:

• overall - tube bass amp head <--check
• 4ea KT88 power tubes, preamp tubes as necessary <--check
• power and output transformers sized to work well at bass frequencies<--check. Hammonds are available and very good.
• hand wired on turret or tag board (true PtP is too messy for my obsessive side)<--check
• open to discussion re: 'ultra linear' design<--check

So far, reasonable.
It will need a custom chassis anyway, I mentioned costs.
The typical homeshop or small Factory does not have the metalworking machinery , a standard chassis maker won't set up for "just one" so your only option is to get somebody who cuts all holes with waterjet, Laser, or some heavy duty CNC machine.
Have around $500 ready just for that.

Or accept a commercial blind chassis (Hammond has them) with holes drilled with standard drills (so no rectangular switches, the IEC hole will be a problem) and large windows (for transformers) hand cut with a metal jigsaw.

Will work, in fact even Factory prototypes are built that way, but will look somewhat crude.

• front panel
• power (on/off) and standby switches
• single input (I only play passive old Fender basses)
• single channel - I'll never understand why so many bass amps have two channels worth of knobs
• single volume control - no master or multiple gain stages
• very basic EQ - passive bass & treble controls - NOTHING else
• NO "bright", "presence" or "deep" switches
• nothing else (no FX loop, tuner outputs, etc.)

Fine.
Front panel will share some of the chassis problems, although to avoid silkscreening just one, now you have the option of Laser Etching on anodized aluminum panels, looks very good.
Not cheap but still cheaper than the standard route.

• rear panel
• standard IEC power cable connector
• fuses (as necessary)
• speakon connectors for 4 ohm and 8 ohm (or selector switch, whichever is easier to implement)
• (2 ohm would be nice, if there is an approprate output transformer that offers it)
• NOTHING ELSE

that's about it, a tube bass amp (150 watts +/-) with a single volume control and the most minimal EQ that still gives some basic control. I own a 1965 Ampeg SB-12 portaflex and I'm aiming for an amp head with the features offered by that amp, only a lot more power.

Agree.
Given your taste in amps, I suggest you buy an old SVT head, and simply not use the 2nd channel, thus avoiding switches, variable midrange, etc.
It already has all you are asking for, plus some extras which can simply be left unused.

It even drives 2 ohms, go figure.

And it will be much cheaper than a custom built one, and probably more reliable than most homemades.

Having an amp built for me is a once in a lifetime deal, so I'm making NO allowances for re-sale value. Also, re: the power output - some companies claim well over 200 watts from a quad of KT88s (Mesa and others). I'm not looking for the most power possible from this configuration - just enough to keep up with a traditional blues band (50s Chicago / Chess type) when we play on larger stages.

It will keep up, I promise.

Oh, and while some third world parts may be unavoidable, my goal is an amp designed and built by people earning live-able wages in a country with full worker rights / protections

Not sure what you mean by Third World parts.
Geographical location is irrelevant compared with machinery and Technology but mainly, who does the Quality Control.

This is the capacitor rolling machine used by EPCOS (former Siemens Halske from Germany, now owned by TDK Japan, both First World Countries by any concept) :
Please click and expand the picture to see details, then reduce and see the NASA quality "clean room" where it works, humans enter there in protective clothing similar to Ebola patient handlers:

This is the actual machine, working in Bawal, India:



These are workers packing the stuff, outside the clean room.
Yes, this is a real "sweatshop in India":



this is a semiconductor production "clean room" in Taiwan or China:





Doubt there's much of this left in US, except companies working for the Government on National Security projects.

And "the mythical old Sprague factory somewhere in the midwest" , by definition has 60's and 70's technology, and caters to Audiophiles and Guitarheads ... can't compete on any other market.

So, thirld world parts it will be.

Unless you pay 5X for dubious old stock ones.

[Leo_Gnardo]

Doubt there's much of this left in US, except companies working for the Government on National Security projects.

Surprise! Global Foundry, Malta NY just south of Saratoga. Nice there's still one.... It's a big complex, they build state of the art sand chips. Only bad news, not expanding at the fantastic rate they claimed it would. Well you can't have everything.

FWIW I worked in a Fairchild Semiconductor clean room late 70's. When they started to take away part of the "suit" and dialed down the clean room specs, I knew they weren't serious, time to go.

Back to the matter at hand. Thinking along similar lines as your SVT suggestion, Lexington our OP might do a lot better financially by finding something simple & reliable rather than hire a build-from-scratch amp. I favor the old Fender Bassman 100, 135 or Showman heads. Maybe a little short on the power figure, say 80 to 100W at clip, but they are simple and can be made to sound just fine. Oh you might get a midrange control (horrors!) but just park it at 7 and forget about it.

[eschertron]

Oh you might get a midrange control (horrors!) but just park it at 7 and forget about it.

That's kind of where my thoughts were going. The OP has spec'd a high and low control but hasn't spec'd what the controls do. Are they knee frequency controls? Cutoff slope control? How ya gonna get your dream amp without a complete engineering specification?

I would be kicking myself if I hired someone to build me an amp and after an hour of playing it had to take it apart and swap resistor values

[Justin Thomas]

Honestly, I likecthe way you think of bass amps. But, hell, do what I would do... get a big ass burned out clunker and gut it & put sumpin simple in it, if you must insist on building something... as long as trannies & chassis are good, works for me. Or, as Juan & Leo said, used SVT or Bassman 135. Too many chsnnels & features? Set it & forget it. Super Twin carcass? V4B? Use any of em til they go totally south then rebuild to your taste. Peavey Mace? I just got one of those for at most half the price of the parts! Again, going for the trannies & chassis here. Faceplates are pretty simple. Hire a local artist to do any lettering/labeling. Does it all end up looking "professional?" Probably not, but it's unique! Heck, I don't mind building the amp, as long as I can recycle the parts... good luck with it!

Justin

[Tom Phillips]

lexington125,

The responses above do good job of addressing your questions. I just add a couple of additional comments.

The original Sunn 2000S head is a very close match to the amp you have requested. Are you familiar with that model? If not I think it would be worth a look. Buying a used amp and having it refurbished may be a good approach to getting what you want.

...hand wired on turret or tag board (true PtP is too messy for my obsessive side)...

Interesting statement. If you tell a builder how to do their work rather than just giving them your specifications you will just further limit the builders willing to consider your one off project.

Regards,
Tom

[loudthud]

The easy way to go on this chassis wise is to start with a 100W Plexi chassis from Weber or Mojo and get a custom front panel from Mojo to cover up the unused holes. Mojo is reasonable if you have a drawing.

For transformers, Hammond will get you to 150W just barely. If you want to go higher, it will double that cost.

If you like the SB12, a Baxandall tone stack will probably get the job done. If you need an up front tone, you better be using a really brite bass with bright strings.

[lexington125]

lexington125,

The responses above do good job of addressing your questions. I just add a couple of additional comments.

The original Sunn 2000S head is a very close match to the amp you have requested. Are you familiar with that model? If not I think it would be worth a look. Buying a used amp and having it refurbished may be a good approach to getting what you want.

Interesting statement. If you tell a builder how to do their work rather than just giving them your specifications you will just further limit the builders willing to consider your one off project.

Regards,
Tom

Thanks to all who replied. (especially JM Fahey!) I agree that an existing amp would be a low cost alternative, but SVTs are just so freakin' heavy/huge, and except for Sunn 200 or 2000s, most of the other suggestions use 6L6 tubes, not KT88s. (I've owned a LOT of bass amps and the KT88 amps just seemed to sound much better for the sound I'm aiming for. That could be due to any of countless circuitry bits, and not the tubes, but I've always had better luck with amps based on KT88 power tubes, especially when compared against 6L6 based amps.) I'd love a Sunn 2000 design, in a box 1/2 that size. (both the Sunn 200 and 2000 are in boxes much larger than necessary) And Sunn models have become stupid collectible; in LA, a nice 2000 can't be found for much under $2k.(before refurb costs) Funny, but while searching the net, look what I found:
Bass Amp | Shaw Audio
Almost exactly what I was asking for, except for a complex mid-range switch and 1/4" output jacks, in place of speakons. But almost EVERYTHING else I requested. Anyone not familiar with Shaw should check out this link. Must contact them tomorrow. And thanks again to all who replied.