gee is this forum a haven for grumpy old men....?

Well at least I can't fit in that category...

but I HAVE been able to SMELL the difference between My old Fender  and my Guild thunderbird amp

August of 69 My amps spent several days of barely being kept out of the rain in my VW....

The fender board grew a whole bunch of green stuff and really smelled BAD...

never did end up playing...

but got to hear Carlos Santana play that new fangled  amp...

Damn that was a long time ago...

https://docs.google.com/fileview?id=0B_cPagiySScIMTc0YzQ2ZDktZjNlZS00ZmIyLTkwZDEtNDM1ZmNhZGU4MDIy&hl=en

Hi Guys ...I recently picked up a Crate G130CXL amp that is missing its reverb tank. Can anyone tell me what a replacement one would be?
I have schematics for it (and its twin Ampeg VH140C) ...but no reverb part#.

The schematic sets are too big to attach.
I put a link and temporarily allowed sharing.On the schematics threads
Email me if you would like them when the file is no longer public.

that "other chip" is a resistor network
http://www.mouser.com/ProductDetail/CTS/767163203GP/?qs=hbgUSdfWRJVF%2fMAjWsBsKQ%3d%3d
here is its Mouser page:


its part number is the top one 767163203GP  CTS is the manufacturer te rest is likely date codes

This is very close to what we Air Force types used to call "brogan maintenance" A boot will work too. :lmao: :lmao:

Not Familiar with that amp...but if it's got the sound you want go ahead and get it fixed. Most of my amps are as old as yours some older. I use at least one of them daily, usually.

As far as the noise yes capacitors can make a buzz  particularly if it is a 60Hz hum or buzz. I've also had that happen from other components.  I have a Peavey Hybrid that starts buzzing about every 10 years and I replace some transistors.

Fender OEM parts don't really include capacitors. There are several brands of quality that they can be replaced with. Sprague and Illinois for starts.  FWIW NOS (New old stock) for electrolytic capacitors is BS. If you're going to change them you want recently manufactured ones.

They have a shelf life and need to be "reformed" if they are old original types for a particular amp. I have never been fond of that process and not particularly successful at it. The reason I bring it up is often if an older amp is brought into service it's capacitors are not necessarily healthy if it has been sitting unused. This applies to electrolytics only.

Bottom line is an old amplifier can be rejuvenated and if you are fond of it's sound it is  worth the trouble.

It still works ...some...so I would venture that it's not in terminal trouble.

Interesting... I have fairchild and a couple of other MPSA56 datasheets on hand from something I had done...everything I have shows the BASE on the center pin.

If you're facing the flat EBC left to right.

   

I think you already have a "line out."  (DI) Direct injection.?? Most marshalls 've seen do.

If you add in another stereo power amp and use the Direct out make sure that it IS stereo out I don;t think it is. Not on any Marshall I've seen.

For one speaker you need a mono power amp anyway. Not stereo.

There are pcb kits useable for LM 1875 or tda20X0 L M3886 amp chips
the most current TDA is 2050 nominally a max of 32 watts.power is dependent on voltage
That level isn't going to make a significant difference UNLESS you add an external speaker for the new amp. In which case the suggestion to add a powered speaker..(new amp in the new speaker box) makes the most sense.
Using a stereo setup is probably not a great idea.You will need TWO speakers for the new power amp There are kits available for either.

Adding one INSIDe your amp you would need something like a 3886 mono amp. This would make significant improvement. Remember hearing is logarithmic not linear. You need to approximately double sound level to make a significant difference. anything smaller than a 3886 near its max voltage supply isn't going to do the job.


One time and money saving thought: using DI if you are "jamming" where there is a PA/mixer  all you really need is a patch cord.

from the data sheet:

"Most power amplifiers do not drive highly capacitive loads
well, and the LM1875 is no exception. If the output of the
LM1875 is connected directly to a capacitor with no series
resistance, the square wave response will exhibit ringing if
the capacitance is greater than about 0.1 μF. The amplifier
can typically drive load capacitances up to 2 μF or so without
oscillating, but this is not recommended. If highly capacitive
loads are expected, a resistor (at least 1Ω) should be placed
in series with the output of the LM1875. A method commonly
employed to protect amplifiers from low impedances at high
frequencies is to couple to the load through a 10Ω resistor in
parallel with a 5 μH inductor."

Well "watts" is often used more as hype than reality IMHO. Some companies rate their amps more conservatively than others. If Marshall is still as conservative with today's SS amps as they were in years past with their tubes. (I'm still using 1982 JCMs) Your amp might very well power external speakers adequately...After all the famed Fender Super Reverb 4X10 was only rated at 40 watts.

Seen plenty of club bands with 25watt Rages (Peavey) feeding a 4x12

The solid state amps I use roughly compare with the Tube amps I use...Gotta remember MOST tube amps favor the midrange...where our hearing does best, so to make a fair comparison you might need to set the mids higher than bass and treble. Probably why Abbot and others had preferences for SS for scooped mids metal sound. Drop the mids to 0 on a JCM for example and it gets weak.

Generally a sealed cabinet takes more power to drive similar to Acoustic suspension Hi Fi speakers. Have to compress that air. It also has different tone emphasizing lows more usually. Although it sounds counter-intuitive however stuffing a sealed cabinet at least 50% with fiberglass insulation can make it behave like a much larger cabinet so that isn't written in stone.

I don't know what speaker is in your amp. If for example it has a 16 ohm celestion and the amp is rated at 30 watts at 4 or 8 ohms just changing the speaker to the lower impedance can make a big difference. Changing to a more efficient speaker of the same rating can make an improvement.

Changing a power amp would be quite doable if there are separate circuit boards for the pre and power amp. Adding a power amp to a line out won't necessarily make it not a combo...Chip amps can be quite small and there may be room to shoehorn one into the cabinet or chassis WITHOUT removing anything. I've tucked 2u worth of Rack equipment into a combo before! (Processor and EQ). Leaving nothing plugged into the original speaker connection shouldn't bother an SS amp.There may even be room OUTSIDE  your chassis above the speaker... I've done that before ...adding electronics and covering everything (except the heat sink) with a modified cap pan from an old Fender

I've never played a SS Marshall but:

30 Watts? should be enough to power a reasonably efficient 4 or 2 12" cabinet... (or 10s)

That should give you that few extra DB

assuming the 30 Watts is output and not power consumption.

I know they are  different...but have played outdoor concerts with a 50 Watt tube marshal (JCM 800) stack

Also does your marshall have a "DI" or Line out  or effects send and return JacK?

If so you could just build/get yourself an external power amp and Speakers.

Simple solutions.


As far as neo speakers...the ones I'm familiar with need too much power for this amp.

Might consider something like Jensen Mod 10-35 speakers.

There is a kit out to turn an epiphone valve JR into s standalone reverb (1 12ax7 and one el84)  You can get junior chassis on Ebay for about 50$.

This is probably the cheapest and easiest to build

sound.westhost.com  (elliot) has an SS reverb project.


The V JR project is probably very similar to my Vintage Guild amp (built in seperate reverb  amp  12ax7 and 6bm8 CTS 8" speaker)  That is a really nice California/surf sound reverb

cheapest may very well be a kit:

power led meter kit:

http://store.qkits.com/moreinfo.cfm/K4307


I found this meter which supposedly will go to 300 watts:
http://www.aqdi.com/powermeter.htm

dbx speaker management:

http://pro-audio.musiciansfriend.com/product/dbx-DriveRack-PA-Complete-Loudspeaker-Management-System?sku=620494

Carvin speaker management:
http://www.carvinguitars.com/products/single.php?product=XD88&cid=61

The amp will clip when it's nearing max power no matter what....Just using at 32 ohms your not likely to blow the speakers.

If you want high volume and clean...your kind of using the wrong kind of speakers to start with.

Those are guitar speakers designed TO start breaking up long before getting to their power rating. Although adding MORE of the same speakers will give you higher volume at the same power level.

A power meter to me is not a solution...I've spent several thousand hours watching meters and indicators. They are good for telling you what just broke, not often preventing it.

Simplest solution...match the speaker power >= amp power output. 32 ohm setup is how you would do that with your speakers.

as far as clipping and speakers...ALL guitar distortion IS clipping Don't run the amp that high? Or get more speakers to match speakers/amp

SO roughly in order of cost

solution 1 run 32 ohm load   speakers ratings and amp then match. Just don't run the amp maxed out. If volume is inadequate without clipping see solution 3.
solution 2 run smaller power amp
solution 3 add speakers such that power amp and speaker ratings match. This will give more apparent volume. EX 4 speakers is louder than 2 at same amp settings. (idea behind the "full stack")
solution 4 add speaker management system/limiting...way overkill for two speakers...cheaper to add another pair

BTW if you're playing bass not guitar forget all the above and get a set of speakers that work for bass You'll eventually kill those with bass. 90 watts of speakers for playing out today just won't do. Maybe try a set of Carvin PS12s or something similar if your budget is tight.(300 watt bass/pa 12 inch speakers)

If you are after really clean Like playing steel etc Might want to look at PA/Bass Keyboard amp speakers too.

Additionally if you're using the Line 6 processing amp models cabinet models etc you probably SHOULD be using PA type speakers as guitar type speakers don't work that well with modeling...they are meant to change the sound (breakup etc)

what impedance are your speakers?  Assuming 8 ohms?  your amp puts out 300 watts at 4 ohms with the speakers parallel.  It would put out 200 watts with 8 ohm load. )according to specs)

For starts; Particularly if your speakers are 8 ohms I would run them in series.  with a 16 ohm load  your amp will produce less watts.

If you have 16 ohm versions and run in series It would beless likely that your amp power would overload the speakers.

Generally increasing speaker impedance isn't going to hurt an SS amp, just reduce power available. (Amp will clip sooner too.)