Amp Guts Photos - Official Thread - Lets see those pics

[FFTT]

As a power systems engineer (yes, aside from amp design, my areas of specialties were industrial controls and power systems, up to 4000 amp, 3 phase and >100kASCC), I can also say that it wouldn't have mattered one bit what the meters were made of in your above examples. Lightning strikes don't care if plastic is used in the covers or not, and the plastics used in meter covers are self extinguishing as evidenced by your photo. In fact, I believe the entire industry has moved away from glass covers because under enough heat the glass can melt (at MUCH higher temperatures) and become a more effective source of ignition.

Normally, the clamping action of the jaws is very, very reliable. It's the same mechanism use in high current fusing. I design with 800-1200 amp fuse protection pretty regularly and have never even seen a problem under any kind of reasonably maintaind conditions.

You are correct with enough heat a glass and gear meter can overheat in the same manner, but they are considerably tougher.

I've had to replace those plastic meters in whole subdivisions from something as simple as a hot to neutral fault caused by a wet branch falling across the conductors or a blown transformer.

The problem is the jaws that hold the meter blades/lugs in place, too many times are not tight as they should be.
The clamps that hold the service entrance cable in place may not have been properly tightened or have loosened from heat buildup.
All of this missed because when the property changes owner or tenant, most of the time no one opens up the meter base to inspect them.
Just taking a reading. Home inspectors are not qualified to inspect the meter base, so short of a turn off/turn on order or meter replacement, no one catches these very dangerous fire hazards.

Many times, sub-contractors are hired to do mass meter replacements and since they are paid by piece work, many of these problems are ignored.

I've been nose to nose with the director of metering in front on the entire staff arguing for full hub inspections any time a property changes owner or tenant. In fact my job security was threatened for addressing this & other safety issues.

There was an apartment building where 14 families were displaced from a fire, after the company changed policy to allow services to be connected under load. I thought they had lost their minds and retired soon after that policy was implemented.

Back to amps, sorry to wander off topic.

 

[agedhorse]

I do agree that proper maintenance is key to safety. This can all be eliminated with bolted high current connections and CT metering, but at an added cost.

 

[bassfreakah]

eden wt-300 one of my faves!!!! Opened it to clean volume, and to check tube. I read somewhere it did no good to roll tubes on this amp because the tube did not effect the sound of the preamp . Is this true?

 

[Mr. Foxen]

If the valve in there is doing something, it should have an effect changing it, but you might just learn that changing valves doesn't make as much odds as people make out if the valve is working right. Might be that it is just operating in conditions where it doesn't add much colour. Character from different ones mostly shows when they distort, because distorting them is pushing them outside their operating spec, they are all designed to act the same within spec, outside it is where variation shows.

Guts of my new custom built round recovered Partridge iron and a PA chassis by Aitken Audio:

Considering doing a run of these to order as I have the scrapper PAs, 50, 120 and 200w. 6SN7 driver stage to make it interesting without complication.

 

[BbbyBld]

I built this out of spare parts. It's based on a '69 1987x super lead with a few tweaks. The wiring could be cleaned up a bit, but it works like a champ. Transformers and choke are Heyboer. It's only 50W, but gets pretty loud with guitar and bass. I'd like to build a cab for it one of these days.

 

[12bass]

eden wt-300 one of my faves!!!! Opened it to clean volume, and to check tube. I read somewhere it did no good to roll tubes on this amp because the tube did not effect the sound of the preamp . Is this true?

Tube swapping can make a subtle difference.

 

[barneybass]

Anyone have an internal picture of the Demeter Minnie 800? What's the transformer and is there an opamp buffer/driver?

 

[bassfreakah]

for that price i hope there is no opamp!!!!!

 

[agedhorse]

for that price i hope there is no opamp!!!!!

Why not? If it's what is the best design choice to achieve the performance goal, and you like the way it sounds and works, and is reliable, why would you care what parts were chosen? There are $100k consoles that use op amps because they are the right choice for the circuits the designer felt gave the best performance. I haven't heard any complaints about how Demeter products perform, have you?

In many cases, a monolithic op amp is better choice than a discrete op amp because of the ability to do things in a design that can not be done discretely, things that require tight thermal tracking, current source symmetry, etc.

 

[bassfreakah]

I just thought using discrete components was the best. I am sure you know much more about it than me Mr Horse. thanks for the reply tho it was rather exciting!!! I love looking at amps insides and listening to cool amp's and music in general.

 

[agedhorse]

I just thought using discrete components was the best. I am sure you know much more about it than me Mr Horse. thanks for the reply tho it was rather exciting!!! I love looking at amps insides and listening to cool amp's and music in general.

There are some simply amazing integrated op amps (and A/D-D/A converters) available that are just mind blowing regardless of cost. With 30 years of designing analog circuits, there's no way in the world we could design an op amp like this that would be manufacturable using discretes. These are what many of the high end consoles are using, and the performance of the part is no limitation to the performance of the overall console.

 

[12bass]

There are some simply amazing integrated op amps (and A/D-D/A converters) available that are just mind blowing regardless of cost. With 30 years of designing analog circuits, there's no way in the world we could design an op amp like this that would be manufacturable using discretes. These are what many of the high end consoles are using, and the performance of the part is no limitation to the performance of the overall console.

Is anyone actually using op amps like the LME49990 in consumer products? I've seen parts like the OPA2134 and even LM4562 in a few high end products, though those are not op amps I particularly like.

 

[agedhorse]

Some of those parts (and others) are being used in pro audio products.

It all depends on the application's requirements and the skill/experience of the designer.

 

[BassmanPaul]

1. 
   
   
2. 
   This is a power amp I built in the early Eightes. The XLRs are used for speaker outs. Right, ground and left. No speakons in those days. I was using an H&H 2x15. Each channel drove one driver. the PCB on the right side rail is the protection circuit. The LED on the centre front panel lights when the speaker outs are enabled. The RCAs send a reduced version of the output signal to a a pair of Vue meters on another chassis. There is a two pin socket that when shorted disables the speaker outs. Thus a simple mute. I should mention that the sleeve has been cut down from its original size. The unit also had a one space panel that housed the two vue meters and a pair of microphone phantom power supplies. The top one space rack panel housed the pre-amp which contained the mute toggle switch.
   
   All PCBs were made by hand. As it sists the brute weighs in at 50Lb. It all worked first time!! It still does function as it should.
   
   i posted this in a thread "DIY bass amp" but I thought it should be here as well. For posterity like!

 

[okcrum]

Nice lacing job!

 

[FFTT]

Impressive attention to detail.

 

[bassfreakah]

sweet and all discrete!!!!!!!!!

 

[okcrum]

Some of those parts (and others) are being used in pro audio products.

It all depends on the application's requirements and the skill/experience of the designer.

For starts, you have to know how to lay out a board so you don't throw away all the advantages of the part you're using.

 

[gregmon79]

I will be posting my Electric here in a bit. Very cool thread idea!!

 

[oerk]

EBS Reidmar 250. This one's still under warranty, but I couldn't help myself.

Now, let me preface this by saying it's the greatest amp I ever owned! Still, I'm not entirely happy about the design. My thoughts about it:
- it's pretty empty in there, but that's to be expected. They could've easily made it smaller, though.
- the whole preamp is mounted on the front PCB. Neat touch: The input jack has it's own little PCB, meaning it can easily be replaced by a generic part if necessary. Nice, because IMO that's the first thing that breaks.
- cooling of the power amp module is done with a thick plate at the bottom of the chassis
- there's a small, loud fan mounted in the middle of nowhere blowing in the general direction of some components. Why, why, why??? My old Tech had the fan mounted in the same location, and that was at least somewhat justified by it being a class AB amp. I've mounted a quieter fan and an on/off switch since. The EBS will get the same treatment when the warranty runs out.