Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kwm488 on May 01, 2012, 09:02:30 am
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hi
my friend pay $3500USD to buy Ampeg SVT VR and SVT 810E. after take out the chassis and take a look, all the parts is bad. The transformer look like china made. Capacitor is brand of Nover. it is not famous brand. and he opamp is TL072 and TL074. and the speaker is made in china Eminence speaker.
i will help my friend to upgrade his amp.
1. change all the capacitor to BC. the board have some small cap, i purchase BC and Nichicon already. but another 8 capacitor is 450v big size cap. it is 3 of 100uf 450v, 1 of 100uf 250v and 4 of 47uf 450v. but i can't find BC for replacement. because BC size more big. in fact, do anyone know can i use 400v cap? and can i use Sprague Atom cap. but it is not Radial. but i see vintage ampeg amp also use non Radial cap and mount to the chassis. and i use sprague atom for all fender amp, they sound always good. and i use Black Gate small cap for pedal, it sound great, but it is stop produce. now, i use BC small cap for pedal cap mod. it sound great and cheaper than Blackgate, also BC almost have all value and voltage and suitable size for pedal .
2. My friend want to change the tube too. all the preamp tube will change to RCA. but the 6 of 6550, i plan to suggest him to use New Tung Sol 6550. in fact, i use gold lion all the way. but Gold Lion no 6550, just KT88. is KT88 same with 6550?
3. the speaker, this is the last step he will do. because speaker is expensive. he plan to use weber new design bass speaker, it is 10FL or 10FH. have anyone have another suggestion?
EDIT... I resize the photo, so it will more easy to load now, kwm488
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/6fe31ac2.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/4364c396.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/d2074c91.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/a3ce4883.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/f2b3fdde.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/23c65cc8.jpg)
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Just curious, why did he pull the chassis? Did the amp arrive not working?
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I think you're making a big mistake. I would not change those filter caps. There's probably nothing wrong with them.
Just because you've never heard of the brand does'nt mean they sound bad or are a problem. Modern eletrolytic caps are made differently than the old style e-caps and are smaller yet can be just as good or better sound/performance wise.
In fact if you cut open a Sprague Atom cap you'll see that what's inside is much smaller than the size of the can it's in.
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My sympathies to your friend. :sad:
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hi everyone
the amp is arrive without any problem. because my friend is curious about what parts inside of this amp after he pay $3500 to buy it.
but i can't find out any parts is good inside. and i believe good cap will sound better. because i try to mod my voodoo lab pedal power cap , i change all SunTan cap to BC (philips) cap. sound improve and better much too much. i am not kidding, because my friend own pedal power too, eveyone agree that my pedal power sound better than original.
and i don't think bigger cap mean sound better than smaller cap. but i know Brand of Black Gate, Nichincon , Elna , BC Philips and Sprague etc...... always sound better . and Black Gate, Nichincon , Elna , BC Philips also are modern eletrolytic caps.
anyways, my friend plan to mod his amp cap. do anyone have some good advice to him? in fact, i consider sprague and BC. but BC size more bigger, and sprague is non radial cap.
To Sluckey, thank you for your help for my friend JTM45 last time. my friend love it much too much .
(http://i23.photobucket.com/albums/b383/kwm488/f3f57612.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/ef2526aa.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/2914674f.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/6b46be6c.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/9a25c595.jpg)
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and i am interested to mod my pedal capacitor and Opamp. it always sound more better. i hope to share what i know to everyone. and i hope someone can give me suggstion.
i hope discuss with everyone about the opamp and capacitor.
recently, i mod my Eventide Delay , original cap is jamicon (made in Taiwan). and i mod it to BC cap and change opamp to AD .
(http://i23.photobucket.com/albums/b383/kwm488/Eventide%20Delay/c807480a.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Eventide%20Delay/e4288710.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Eventide%20Delay/eff421c0.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Eventide%20Delay/63235bf4.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Eventide%20Delay/9a83a551.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Eventide%20Delay/85d4865e.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Eventide%20Delay/77b86866.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Eventide%20Delay/c67ccbe2.jpg)
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sorry to upload more. once more mod for TC Hall of fame reverb. it use lot of SMD caps and use programming clip, so i just change 4 On 33720 opamp to my favour AD 8620. and i change two filter cap from nichicon and Wincap to BC. i just do it today. i do compare before change it. it really sound better.
(http://i23.photobucket.com/albums/b383/kwm488/TC%20Hall%20Of%20Fame/151d4947.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/TC%20Hall%20Of%20Fame/6454fdd6.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/TC%20Hall%20Of%20Fame/b043d79a.jpg)
i learn from my to use solder to remove SMD opamp.
(http://i23.photobucket.com/albums/b383/kwm488/TC%20Hall%20Of%20Fame/b14aa968.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/TC%20Hall%20Of%20Fame/550c4ccf.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/TC%20Hall%20Of%20Fame/bfb8d1b5.jpg)
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6550 replacement
One of my tube cross reference sources indicates that the KT88 will replace the 6550. But you might not want to replace a KT88 with a 6550, because KT88 is equiv. to 6550A,
source of info was wikipedia- list of vacuum tube
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hi
in fact, my friend plan to use 6550, not KT88. do you have good brand of 6550 recommend? he just know new tung sol 6550 is good
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Winged (C) 6550A is what I use in an old SVT I have. Very strong and punchy on low end. Not sure who owns the Ampeg name of if they are still a separate company. I know their lines of products have gone downhill since 1995 when they came out with their first piece of crap. That 4, 12's cabinet they put their name on. I am not sure, but Korg may own them. You see Ampeg products where Korg is sold most of the time.
I am sorry as well. It may turn out to be a great amp tho. I gave up on their products long ago. For me, I use a SWR redhead if I am playing bass and if I get the opportunity to play a larger place, then I will get someone to help me load that old Ampeg with the 8, 10's cab.
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I have worked on two of the new China made SVT CLs in the last year.
I have nothing good to say about them.
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The electrolytics look like ChemiCon caps. Nuthin wrong with that but I could be mistaken. Start with the speaker. that's the main problem I see.
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All the filter caps are brand of Nover. Do anyone know this brand and where do it make?
As my experience. Speaker is most important. But my friend will not start withe speaker first , it is too expensive. Weber bass 10FL is $90 each, $90 * 8 + shipping. Quit expensive.
And replace all caps may just $100 only.
If my friend want to change speaker. What speaker should he buy? And what ampeg use in golden 70s ? CTS speaker?
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As the power tube. I always use SED before. But I use gold lion now, I think it sound better that SED. Honsetly, I think SED 6550 will sound better than Tung Sol 6550. And I love SED 6L6GC and EL34. But I use gold lion KT77 to replace SED EL34, sound better. Unfortunately , Gold Lion no 6L6GC.
Thank to suggest me SED. I forget SED have 6550
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The electrolytics look like ChemiCon caps. Nuthin wrong with that but I could be mistaken. Start with the speaker. that's the main problem I see.
As my experience. Speaker is most important. But my friend will not start withe speaker first , it is too expensive.
I don't know what country you and your friend live in or why your friend bought this amp, but I think your friend made a mistake paying $3500 for this amp and now thinks he can get a great sound by changing a few small priced parts.
Changing the filter caps in a low voltage SS stomp box, IMO is very different than in a HIGH Voltage/HIGH Current tube amp with the same resulates.
Plus, it's a pc board and at the $ price he paid for it and who knows if that board will even take the parts changes without the traces pealing off of the board, is anybody's guess.
So, if it goes bad while you're changing the parts, trying to help your friend, now what? :dontknow:
Brad :think1:
IMO, Richards right, best place to start, at this point, is change the speakers .
But, your friend doesn't want to spend the $$. Now what? :dontknow:
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Hi
Me and my friend live in hong kong. Here not too much good bass amp for sell. SWR is no stock, don't know when back order, and someone say new trace bass amp is not good.
And I really don't know much about bass amp before. I just know ampeg is famous brand. After trying it and comPare with other bass amp , it sound good. So my friend buy it.
But I can't beleive the cab cost $1100 and give me china made speaker. We go to ampeg web to see the spec very care before purchase . Ampeg never mention it is china made speaker.
Anyways, my friend will change the speaker finally. But he just pay $3500, so he want to change some cheaper parts first.
Can someone suggest him speaker?
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I'm sorry kwm, our good Hong Kong friend. :icon_biggrin: I'm not trying to work aginst you.
If I spent $3500 on a brand new amp, I would not want to spend more $$ on speakers either.
But I still don't think that changing the filter caps will make that much or as much differance as when you have changed filter caps in your stomp boxes/pedals.
Brad :icon_biggrin:
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hi willabe
we just discuss , i don't think you work against me. i hope to listen more advice.
in fact, my friend spent $3500, i really don't know will he spend more money on speaker. in the other word, if he sell those china made speaker on ebay, how much he can sell?
as the filter cap. in my experience , it will sound different. i own vintage 1970 fender twin reverb, i use F&T cap, and sound improve after i change it to Sprague Atom. and i help my friend to mod his china made AC30. i change all china cap to Sozo and Sprague Atom. sound hugh different.
my friend say he don't mind to spend $100 to change the caps even sound improve not too much. For me, i always use good brand filter cap for the pedal and amp, because changing good brand cap will be relieving .
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we just discuss , i don't think you work against me.
Good. :laugh:
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... Not sure who owns the Ampeg name of if they are still a separate company. I know their lines of products have gone downhill since 1995 ...
St Louis Music (who used to bring you Crate in the 90's-2000's) bought Ampeg in 1986. Mackie, now LOUD Technologies, bought St Louis Music in 2005. So now Ampeg, Crate and Blackheart are all cousins.
Draw your own conclusions about their production methods and cost-saving.
I just know ampeg is famous brand.
Yes, it was. But I noticed you didn't copy a 2010 Marshall amp, but a 60's Marshall Superlead. In the same way, Ampeg amps from the 60's-70's were excellent, and now less extraordinary.
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as mentioned Ampeg is now the same company as Mackie and Crate. the new SVT's are different from the old ones. if you want an old one you should buy one.
in my opinion if you want to upgrade a new svt you should take out the circuit board and replace it with a better one with quality components and the old SVT circuit. and then you'll probably replace the tube sockets and the wiring too. and maybe you'll want to replace the transformers too so you'll spend a lot of money and time... i don't think replacing the filter caps will do a lot for you. there is so much other stuff going on in that amp that you probably won't hear any difference. it's probably cheaper to build a clone of the old SVT from scratch.
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Hi
In fact, I hope to make sure something first.
Do anyone know the new ampeg SVT and vintage SVT same circult?
And do anyone know the new SVT transformer is good or not? Is it china made transformer?
As the transformer, I will not help my friend to change it. It is crazy heavy, mean crazy shipping. I will advice him sell the amp if he need to Change transformer .
As the tube socket, I think it is Belton. My friend plan to change the tube , caps and diode. In my experience, if the transformer is good enough, change the caps will sound better. Because bad transformer will block the good tone.
So I really know to know is old and new SVT circult same?
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I would start by replacing that cheap power cord. :grin:
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Hi Sluckey.
my friend use Furutech power cord already. sound much better. and power cord and tube can use for any amp. so i think it is worth to upgrade, if my friend want to sell his amp, he can keep the power cord and tube.
sluckey, do you mind to let me know what brand and model of power cord you use? i try monster , Belden 82830 and furutech only.
and i remove all plug fuse. remove fuse sound more better. all UK wall plug have fuse inside , but US wall plug style no fuse.
(http://i23.photobucket.com/albums/b383/kwm488/New%20Marshall%201959%20Super%20Lead/65d470be.jpg)
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Er, why remove the fuse from the plug? Apart from being an important safety device, the electricity has travelled a few miles over whatever power cables - does missing out 20mm of wire in the plug at the end of that help? You really going to hear the difference, on a bass amp? !!
Never seen that done before!
Does the lid go back on with the fat mains cable?
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I'm a power cord hoarder. I can't pass up a power cord. If I find an IEC cord that's not connected, it goes into my stash. Some of my better cords came from the dumpster behind Best Buy!
But my prize is a pair of NOS military grey 8 foot shielded IECs. They sound super! And very quiet. I'm saving them for something special.
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Er, why remove the fuse from the plug? Apart from being an important safety device, the electricity has travelled a few miles over whatever power cables - does missing out 20mm of wire in the plug at the end of that help? You really going to hear the difference, on a bass amp? !!
Never seen that done before!
Does the lid go back on with the fat mains cable?
he listened a bit too much to the audiophile community. they have more funny stuff to discover if you look around a bit. like porselain cable holders to make sure your speakercables don't touch the ground to have less interference coming from the earth...
that being said, it's all subjective ofcourse. if you like to spend extra money because you believe it's better, good for you.
and yes, the transformers in the new SVT are chinese and yes, the amps are very different from the old SVT's.
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To sluckey
do you mind to upload some photo of NOS military grey 8Ft shielded IECs?
i bought some NOS Western Electric thick 8awg wire to be a speaker cable. after i try Kimble speaker cable, i never use Western Electric anymore.
some Old Hifi guy tell me old wire copper more pure . but i don't think so. i believe 2012 company can make more pure copper wire like OCC copper cable. so i use New cable only.
maybe old wire good for vintage amp.
To JB
honestly, remove the fuse will sound quite better. this is a reason why some Hifi fuse price of $50 USD. before i try it, i think that fuse for crazy and stupid people. after trying it, i pay $150 to buy 3. but i just for audio, some people buy it for TV, they said video quality is better.
and the point is not missing out of 20mm cable. inside fuse, it is very very thin wire. Like even your computer CPU very fast, but your Hardisk is very slow, your computer performer is slow too. this is a reason why remove fuse will sound better. as the safety problem, i think the plug fuse is useless, because if your amp have problem, it should blow the amp fuse first, it should 1A or 2A only. the plug fuse is 13A. and all US plug no fuse inside the plug.
last, i compare common power cord and furutech cord for marshall amp and bass amp. sound hugh different. and compare power cord with fuse and without fuse. without fuse sound better.
I don't believe everyone, i just use my ear to hear which one is better.
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do you mind to upload some photo of NOS military grey 8Ft shielded IECs?
I'm sorry. I cannot take photos of them in their stock form due to national security policy. One day (hopefully soon) I'll have a worthy project and once I modify the cords I can take some photos. I've been thinking about a dual lamp limiter.
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for this SVT VR. it is 100% china made transformer? do anyone know what brand? and the old and vintage SVT circuit really different? do anyone where can i download svt vr schematic?
in fact, which bass amp is good parts inside. it is impossible to request the store open the chassis to take a look before buying it.
in my experience, mesa boogie is the only amp i pull out the chassis , but i can't do anything (mod). because they use all good parts.
this is my dual rec. it is Daly resistor, Orange Drop caps, Sprauge Atom, nichicon caps , USA transformer. i just change mesa boogie preamp tube to RCA and power tube to SED.
and what brand of bass amp is worth to buy? SWR??????????? i know SWR transformer is made by Mercury. is SWR amp use Good parts? how about aguilar bass amp? do anyone have their photo of the parts inside the chassis?
(http://i23.photobucket.com/albums/b383/kwm488/Mesa%20Boogie%20Dual%20Rec/IMG_3937.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Mesa%20Boogie%20Dual%20Rec/IMG_3938.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Mesa%20Boogie%20Dual%20Rec/IMG_3939.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Mesa%20Boogie%20Dual%20Rec/IMG_3943.jpg)
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and i want to google some amp photo (i want to see the parts inside the chassis, i want to know what transformer, caps and resistor) . what word should i type to serach it
thank
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i have seen quite a lot of bass amps that are used a lot in a rental company. the ones that almost never break are mesa, ampeg svt classic (the OLD ones), GK, SWR, markbass and aguilar. GK (GK800) being the somewhat cheaper workhorse but very reliable. i've also worked on a trace elliott V8 and i normally wouldn't really reccomend trace amps but this one was very good and well built. i think there is also a V4 and V6.
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i think i don't consider trace bass amp. the old one is very good. but i hear lot of bad review on the new trace amp.
and mesa boogie never use bad parts, but my friend don't like their bass amp.
and Aguilar and markbass, my friend really interested. one of my friend own markbass, but it is use acceptable parts only.
do anyone have SWR and markbass photo of chassis?
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Winged (C) 6550A is what I use in an old SVT I have. Very strong and punchy on low end. Not sure who owns the Ampeg name of if they are still a separate company. I know their lines of products have gone downhill since 1995 when they came out with their first piece of crap. That 4, 12's cabinet they put their name on. I am not sure, but Korg may own them. You see Ampeg products where Korg is sold most of the time.
I am sorry as well. It may turn out to be a great amp tho. I gave up on their products long ago. For me, I use a SWR redhead if I am playing bass and if I get the opportunity to play a larger place, then I will get someone to help me load that old Ampeg with the 8, 10's cab.
Ampeg is owned by Loud Technologies.
Wing C is the BEST 6550
you may find replacing the caps a waste of time
tl072 and 74's are the opams that belong in the SVT
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> i think the plug fuse is useless, because if your amp have problem, it should blow the amp fuse first
If the power cord is crushed, it will short. The amp fuse will not blow, it isn't getting power. The power cord between the wall and the crushed part will burn.
That's why there is a fuse in the plug.... to protect you from damaged cords.
> all US plug no fuse inside the plug.
We do a lot of dumb things in the US. Mostly because the US electrified before good plastic insulation, and our electric code system is weak. Also we use many circuits with fairly low-current breakers, 15-20A. Similar to your 13A plug fuse. Lamp-cords will usually blow the breaker without starting a fire. Under post-WWII UK wiring systems, there may be 30A to 50A available at every wall socket (because there may be one circuit for an entire floor or house).
I'm not saying that you are sure to burn up the house if you bypass the plug fuse. You pay $2.50-$15 per foot for cable, you will be very careful not to crush it. It also look heavy-duty, hard to crush. This is very different from a table-lamp in a bedroom with the cord running under carpets, mats, old books.
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Hi
Thank you for your advice.
Before I do this, I do a lot of research. Almost all hifi guy in hong kong will bypass the fuse.
And if the cable is short. House electric protector will break even I don't bypass the fuse. Moreover, my power socket extension with 13A fuse. So it is enough. If the socket extension plug have fuse, socket extension have fuse, power cord have fuse. One fuse will lower 5% quality. The result is 15%. So I just keep socket extension fuse, but I install furutech fuse.
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i think i don't consider trace bass amp. the old one is very good. but i hear lot of bad review on the new trace amp.
and mesa boogie never use bad parts, but my friend don't like their bass amp.
and Aguilar and markbass, my friend really interested. one of my friend own markbass, but it is use acceptable parts only.
do anyone have SWR and markbass photo of chassis?
i didn't say anything about the quality of the parts. and from what i understand you see quality parts as expensive parts. i see quality parts as parts that work well. that's a difference.
what i said is that those amps are reliable. the build quality is good.
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I can understand the guy not wanting to spend any more money. I'd suggest finding a good speaker cabinet you can borrow for a test drive. This may convince him of what the main problem is.
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Birt:
"what i said is that those amps are reliable. the build quality is good."
sorry , i don't understand. one of my friend work in music center who repair amp. he said that he always repair marshall, fender , but never boogie.
normally, i think good parts (not mean very expensive) will more reliable. am i correct?
RicharD:
in fact, i don't advice my friend change the speaker. i will advice him to sell his cab and build a custom cab and buy speaker. so he can save more money. do anyone know how to build cab? what wood i should use? and what brand of bass speaker?
and can anyone suggest me the forum which discuss cab, speaker mainly?
follow is mark bass photo, i think the parts is just fine. i think the most important is the transformer , if the amp transformer is good, i can mod the caps by myself. i email ampeg, he say he use oversea transformer.
(http://i23.photobucket.com/albums/b383/kwm488/Mark%20Bass/8be7ebb4.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Mark%20Bass/7cecd681.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Mark%20Bass/8c44952e.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Mark%20Bass/ab7a6138.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Mark%20Bass/d09911d6.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Mark%20Bass/8fb2be59.jpg)
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Birt:
"what i said is that those amps are reliable. the build quality is good."
sorry , i don't understand. one of my friend work in music center who repair amp. he said that he always repair marshall, fender , but never boogie.
normally, i think good parts (not mean very expensive) will more reliable. am i correct?
RicharD:
in fact, i don't advice my friend change the speaker. i will advice him to sell his cab and build a custom cab and buy speaker. so he can save more money. do anyone know how to build cab? what wood i should use? and what brand of bass speaker?
and can anyone suggest me the forum which discuss cab, speaker mainly?
good parts are just good parts. if the amp is not built well it will still not be very reliable. but if it is built well and uses cheaper parts that will work (but are not the best) it will still be a reliable amp.
so you want to advice him to build something himself but you don't have a clue how and what materials to use? so it's going to be a mediocre first try. what good is it to make sure you have all the best parts in your amp and then build a speakercab that will not meet the standards of what you can buy from a professional?
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KWM488 you have come a long way since that JTM45 thread a year or more ago. You have more guts that i do in opening up that new Ampeg SVT. It's really is sad how there making most amps today. They work but whats inside and how there layed out is scarry
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This is just my opinion, so don't take it personally. Bass Speaker Eminence Legend B102 in 10 inch, 2 are plenty as they are really 200 watt. Ported cab with a APT:200 supertweeter in the center top, this is Eminence as well. Eminence makes so many different speakers. Some are the best you can get, but they contract build and must meet requirements/price of the Manufacturer.
The last Ampeg cab that was any good was a 4, 12's guitar cab. It was loaded with Legends. The cab was made from 1992 to 1995 when Guitar Center got some special made ones. They looked the same but were made of particle board, 5/8 inch and contracted with Eminence to make the cheapest possible speaker. Guitar Center sold this cab for $299 and other music stores who had the real ones in stock got screwed.
Now, here comes my opinion part. Sell the ampeg and cut your losses. The money it is going to cost you to rework it is going to be greater than the loss of reselling it. SWR is available in Hong Kong, but your friend may want something else, SWR is just my preference as they are durable and great sounding IMO. Mark Bass was suggested and I have a friend who uses and really likes it.
I also have a Macro-Tech MA-3600VZ power amp with a mini 4 channel Makie mixer and this makes a great bass amp, bridged mono running a 2, 15's cab with 2 Eminence Legend CB158, 300 watt. It has to have a nice compressor, but it is a great setup. I use a joemeek oneQ I got off ebay for $220 shipped. Power amps for sound systems are cheap in the used market and it is really surprising how nice of bass amps they make. It all is in a 6 space rack and using the mixer allows me to dial in exactly the amount of effects I want to use. Push one button and the effect is on. I paid more for one of the speakers than I paid for the amp. I've got $1300 in the whole setup but everything was used except for the speakers. Like I mentioned before, I mainly use a SWR Redhead as most of the gigs I play are small rooms and it is so easy to move around. All I have to do is plug in the power, plug in my bass and I am ready. Setup time is less than 5 minutes and I don't need to rent a moving truck.
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birt
because my english is not good, so i don't understand before. i think you mean first thing is the circuit. i am agree. my friend tell me, like boss pedal, their circuit is not good, so even i replace all good parts, sound will not good. like klon, it is good circuit, so it sound good even he use common parts only. but my point is good circuit with good parts, sound will better than common parts.
and i think i should correct the title to be should my friend upgrade his ampeg SVT VR caps.
Plexi50:
i remember i post the jtm45 is a few month ago. finally, it is fix, and thank you everyone do your best to help me. my friend don't mind to opening his new ampeg svt, so i do it. otherwise, i will not know ampeg charge $2500 to give this parts for people. and my friend really hear the different after i change a good cap to pedal and guitar amp. so he believe his ampeg can sound better after recap. anyways, i will let my friend choose to do or not. his choice.
ed chambley
in fact, i will suggest my friend to sell his cab if he want to change speaker. he better to build a bass cab and install speaker by himself. as the Eminence, i hear this brand. but i never try it. i just try celestion , Jensen and weber only. i don't like jensen. i own P10R before, sound very thin, too treble , and i like weber speaker. weber just realize bass speaker, have you try it? the model is 10FL and 10FH.
if my friend want to build a cab in the future. where can i buy the hard wood? what wood should he use? i don't want to use polywood anymore.
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Madness with all the money he's going to dump into this amp he could of bought used early 70s one off of eBay. Made in China or not that's a brand-new amp he's hacking up to switch all the caps in which are good caps...
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Madness with all the money he's going to dump into this amp he could of bought used early 70s one off of eBay. Made in China or not that's a brand-new amp he's hacking up to switch all the caps in which are good caps...
Yes.
Sell the ampeg and cut your losses. The money it is going to cost you to rework it is going to be greater than the loss of reselling it. /quote]
Yes.
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anyways, my friend bought this SVT VR. as the recaps, this is just $100 USD. i think it is worth to do. of course , i don't charge the labor fee, he is my friend
i can't imagine the shipping to hong kong if he bought a vintage svt from ebay. and the problem is that he need to pay installments.
this is a reason why he bought from local music store.
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Regarding the speaker: The BP102 is a fine speaker as Ed says. A ported box (19mm Russian plywood) is fine if you have limited wood skills. I recommend going to Bill Fitzmaurice's site and look at the plans for the Jack 210 or the DR250's if you have wood skills. If you need more bottom, add a T39 folded horn sub. Miles better than a direct radiator. 103+ dB sensitivity will bury a box with the usual 90-95 dB sensitivity. Remember for every 3dB increase, you need double the power. 12 dB difference means you need sixteen times the power to begin with (1 watt vs 16 watts for the same 103dB) 16 watts gives the horn 115dB, to catch up the direct radiator needs 256 watts. Next step is a doozy: for 118dB the horn needs 32 watts, the ported box needs 512 watts. By this time power compression has set in amd the ported box driver is a smoking wreck
Regarding the amp: tell your friend to sell off the Korg/Crate/Ampeg piece of Chinese engineering (somebody will want the recapped mod and pay handsomely for it) and get a real 70's SVT or Fender Bassman. I'm sure that Doug would be happy to sell the parts to make a decent Bassman clone for a lot less than $3500.
Just some food for thought... happy building!
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thank
and do anyone know what brand of this cap?
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/ab06c7ff.jpg)
also, i change the 2 nover caps to nichicon.
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/cee35c1b.jpg)
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Wow! Got some sound clips?
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I record sound clip before changing caps. But I can't listen any different. And I just receive ampeg schematic, that caps for DI.
Sluckey, do you know what brand of blue color cap?
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replacing those caps will most likely void his warranty (if he has one) from what I understand ...Ampegs have a great warranty.....so even though it only costs him 100 dollars ...if a tranny goes or anything else he's on his own .....
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I don't know who made them but they look cheap. I bet they don't sound very good.
I'm concerned about that brown one.
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Ampeg may offer very good warranty in USA. But it is another story in hong kong.
And I see this photo in Hk forum. But I don't sure this caps is fake or real.
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/dc2780ca.jpg)
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The blue caps is very cheap . I will use wima if I use this size caps. But I decide to use mustard to replace it.
As the brown cap , it is $0.3 usd for one here. I will use wima to replace it.
Or other suggestion?
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do you know what brand of blue color cap?
The blue cap is an MMY cap , says so right on it. Metalized Polyester film. Made by Yuchang Electronics Co. Ltd.
http://www.yuchangelec.com/fskr_mmy10.htm (http://www.yuchangelec.com/fskr_mmy10.htm)
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Thank you for your information.
Btw, is it good?
And I use wima all the way if I need small size mpf.
I see ampeg use wima in few year ago amp. But it seem to use more cheap caps in this year amp
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The mmy caps are made by yu chang electronics co a Korean Company
I did a search mmy capacitor
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저희 유창전자공업(주)는 앞으로도 고객 여러분의 성원에 보답하고자 늘 제품품질 향상과 고객의 만족을 위해 전직원이 일심으로 단결하여 앞으로도 더욱 존경받는 회사, 사회에 기여하는 회사로 만들어 가도록 노력하겠습니다.
"...try to contribute to society as a company."
Not a "cheap chinese company".
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hi
i try to remove the the blue caps and change it to mustard.
but the result is not good. sound too hard, the bass is over, sound is overdrive little bit.
but i really don't understand why. because mustard caps good quality than that blue caps.
and vintage old SVT is also use the philips yellow caps.
and even i change the 3 preamp tube which for power tube section. this happen also, sound too hard, bass too much. i can't believe RCA tube bad than sovtek.
now, i guess will the problem come from the bias. because this amp have two bias led , but just one led is flash during playing
please advice me, in my guitar amp experience. good cap will not sound bad than bad cap. just different taste .
and i upload this parts schematic also. is the cap for the bias?
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/3acc18d2.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/bfb0749d.jpg)
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IF YOU DON'T KNOW WHAT YOU'RE DOING, KEEP YOUR HANDS OFF!
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My purpose is change all cheap cap to good cap. But sound will never worse after upgrade. Why?
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IF YOU DON'T KNOW WHAT YOU'RE DOING, KEEP YOUR HANDS OFF!
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looks like the sozo is in the wrong place?
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And I plan to use wima to try again.
But it is strange, even retune with RCA, sound strange too. But I don't think RCA bad than sovtek
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I change the mustard caps to wima black box . It sound back to normal. Wima and blue cap are mmp also. But the black box is the hifi grade cap.
And I change three 100uf samyoung cap to BC caps. Sound more punch , treble more better, sound more power
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/6d2b63e0.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/bad86974.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/6a4ebf78.jpg)
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Sweet mercy, man. You guys should've just returned the amp after cracking her open. That is a HUGE amount of money to spend and the fact that you are essentially in the process of gutting this amp is crazy. Whoever suggested starting with the speakers was not trying to mislead you; you will end up spending so much money on marginal gains that won't even be noticed in a band setting, my friend. Speakers will give you the best bang for the buck. Take the head with you and go cabinet shopping.
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hi
i understand speaker is very important. my friend will make his own cab and buy weber 10FL bass speaker.
anyways, he want to change the caps first. it is cost $100 totally for all caps.
follow are philips caps, will install on friday, i will take a videos about before and after
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/341fb26e.jpg)
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i install all BC cap to my friend SVT VR today. it sound better definitely. sound more fat, more detail, more power , more punch, more layer , smooth the treble and mid. i believe good filter cap can give the amp enough power.
i higher recommend to change the bad filter cap to better brand filter cap.
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/f701af55.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/23493033.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/3bfdbfae.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/53ff26e1.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/27e23eec.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/548d78a9.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/8988f50c.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/9f086225.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/c377ff0e.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/76905e10.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/99de5036.jpg)
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/6bbf5b06.jpg)
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My friend say sorry, he play bass not very good.
this is the video before mod
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/th_54742d95.jpg) (http://s23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/?action=view¤t=54742d95.mp4)
this is the video after mod
(http://i23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/th_870cf5c6.jpg) (http://s23.photobucket.com/albums/b383/kwm488/Ampeg%20SVT%20VR/?action=view¤t=870cf5c6.mp4)
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I can hear the change and I like it. You did your friend a great favor. This is a vintage amp forum and many of us do not enjoy working on cheaply manufactured factory circuit boards. You need to have a steady hand and nerves of steel to do this work. Thanks for sharing the project with us. Jim
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sounds better allright - i bet you notice the change even more when you play using your fingers though?
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When I first saw this thread, I was skeptical that there would be a noticeable improvement in tone with the component changes. I'm happy that I was proven wrong. It certainly sounds like there is more bass with a rounder tone. What a great deal of work you put into this amp!
j.