Crest 8001 - Value
Printed From: Speakerplans.com
Category: General
Forum Name: Amp Forum
Forum Description: The 'Stopping Jake Fielder moaning constantly' forum description...
URL: https://forum.speakerplans.com/forum_posts.asp?TID=97861
Printed Date: 16 April 2024 at 8:33am
Software Version: Web Wiz Forums 12.06 - https://www.webwizforums.com
Topic: Crest 8001 - Value
Posted By: levyte357-
Subject: Crest 8001 - Value
Date Posted: 21 February 2017 at 1:30am
|
Been offered 20 year old version of one of these, wonder what the people here think it is worth !? Told years ago, certain version is headache to repair/service, assuming it's the older one?  ------------- Global Depopulation - Alive and Killing. |
Replies:
Posted By: B_Bender
Date Posted: 21 February 2017 at 5:15am
|
A 20 year old power amp. £100...? Full re-cap would be required, major cleaning job as well.
|
Posted By: jbl_man
Date Posted: 21 February 2017 at 9:06am
|
Price entirely dependent on condition Lev,is the same with a 20 or even 30 year old Crown,a lovely clean one will appeal to the hifi bods and make a good price,a scruffy one,well,as mentioned above,£100-ish. ------------- Be seeing you. |
Posted By: levyte357-
Date Posted: 21 February 2017 at 10:03am
|
Thsnks guys. Wouldn't even consider it, if it wasn't 8001. Wondering if it will be money pit, like buying classic car.  ------------- Global Depopulation - Alive and Killing. |
Posted By: U.Viktor
Date Posted: 21 February 2017 at 12:31pm
|
Most of you thinking about only Electrolyte capacitors what seriously defines lifetime of power electronics (amplifiers). Unfortunately this is not so simple in practice, power semiconductors also have "wearing out " effect which depends on how many and how big heating up and cooling down cycles received. In the analog amplifiers the dissipated energy of the power semiconductor is modulated by twice of the frequency of the amplified signal. Sharp temperature changes in the junction layer making some changes in the crystalline structure of the semiconductor, which may results failure sooner or later. This effect is present in switching-type of semiconductors (sw MOSFET, IGBT) too , but their structures have been designed to better handle this issue. Sorry to say this but the time has well went over the type of dissipative circuitry (analog, AB, classH), their linear transistors have never evolved to those levels like the switching couterparts. It means that the available low number of linear power devices are lagging ~20years back of today's "conventional" power switching devices, in terms of power cycling capability, reliability, maturity of crystalline structures. |
Posted By: levyte357-
Date Posted: 21 February 2017 at 12:44pm
Mein Gott, I 100% agree with one of Victor's posts!!!  ------------- Global Depopulation - Alive and Killing. |
U.Viktor wrote:Posted By: Earplug
Date Posted: 21 February 2017 at 3:33pm
|
"Mein Gott, I 100% agree with one of Victor's posts!!! " Now that is worrying! "Sorry to say this but the time has well went over the type of dissipative circuitry (analog, AB, classH), their linear transistors have never evolved to those levels like the switching couterparts." That's quite a sweeping statement. I still have amps made from/around the old Maplin/Hitachi MOSFET modules working fine after 30 years, never mind my Crests, etc. One guy I know recently got rid of his Ram Audio lightweights and replaced with 8001's. He's never been happier. And how would you define something like Lab Class TD - analogue or 'digital'? On the subject of the 8001, one thing you could do is stick a multimeter on the output and see if there's any (DC) drift. That is quite a good signal of the health of the amp. ------------- Earplugs Are For Wimps! |
Posted By: U.Viktor
Date Posted: 21 February 2017 at 7:28pm
|
The Crest 8001 is a 2x 1200W (4Ohm) amplifier as far as I remember. May deliver 1800W peaks on 4R load for short periods... Its weight is ~40kg, consumes 3 or 4 rack unit spaces, has terrible power factor, poisoning mains with injected current peaks, its power valid only rock solid 220Vac due non regulated power supply.. Despite its large number of output transistors, did not perform very well on certain speakers because the output stage did not like largely shifted output current vs. voltage due heavy dissipation in the endstage. As I remember it has a momentary U*I dissipation protection per output transistor arm and causes terrible sound effects when acted sometimes ;_) So let us say the linear amp has made to deliver 50A peaks but if you have just half the output Voltage the output momentary current shall not exceeds 25A, which is typical with resistive loads. Unfortunately the real speakers like to act as motors//generators so sometimes the maximum source and/or sinking current capability of endstage is required not only at time of peak Voltage events.. Here most of the linear amplifiers fall and properly constructed class-D win, which can deliver (or sink) its nominal output current at ANY output Voltage without the risk of exceeding momentary dissipation limits of the output power devices. This small trick is the secret sauce of good speaker control, what nobody tells you. |
Posted By: nickyburnell
Date Posted: 21 February 2017 at 8:47pm
This is brilliant. You keep up all the negativity and persuade the sheep they are all useless now. The rest of us will then rejoice is a market flooded with £100 8001's and PPX's etc. Good job, keep up the good work Wow, sound must have been shit for the last 20 years ------------- It's everything, not everythink! |
Posted By: luton_soundman
Date Posted: 21 February 2017 at 9:28pm
|
From the guy who loves pkn ------------- Sound Hire/Sales new/used equipment. |
Posted By: kedwardsleisure
Date Posted: 21 February 2017 at 10:16pm
|
Parts for those old crests are getting dear now. A set of electrolytics could be as much as £450. You will find out if they've failed when they spurt boiling electrolyte all over the board in the middle of a bass drop.  ------------- Kevin North Staffordshire |
Posted By: nickyburnell
Date Posted: 21 February 2017 at 10:39pm
|
Better start a Crest breakers yard then :) ------------- It's everything, not everythink! |
Posted By: kedwardsleisure
Date Posted: 21 February 2017 at 10:57pm
|
to be fair the CA series have been coming in with vented capacitors for a few years now, so not just the 7/8/9000 series. Luckily a set of caps for a CA12 is only £150-200 trade but they aren't as big as the ones in an 8000 ------------- Kevin North Staffordshire |
Posted By: sajti
Date Posted: 22 February 2017 at 5:40am
|
8001 was my favourite amplifier to drive the bass. Of course it was about 20 years ago. I don't agree, with Viktor, this amplifier has very good sound, it was well designed, bullet proof build. We had about 20 pcs. and we lost only 2 channels in 4 years, even with heavy disco usage. It was easy to repair, and even easy to make it more powerful :) Agree, that the capacitors are expensive, but it's quite checp to replace them with the new snap in version, with a small pcb. Sajti |
Posted By: Dub Specialist Sound
Date Posted: 22 February 2017 at 11:36am
|
Its amazing how so called crap tha are still dropping heavy the old crest still doing the rounds in the soundsystem scene come on ppls, agreed nik ------------- Musical Roots Reggae Vibration is Life! for music is sound...sound is vibration...vibration is energy... and energy begets life. Therein lies my passion!...MUSIC IS LIFE... |
Posted By: Dub Specialist Sound
Date Posted: 22 February 2017 at 11:39am
|
We know tha hold there price, not 100% bout the really old ones, but tha still going rate can be 400-500 depends on condtion my 2p man love crest all day man, wernt 3/4 grand new for nothing oo series....but do understand the age thing with them..
------------- Musical Roots Reggae Vibration is Life! for music is sound...sound is vibration...vibration is energy... and energy begets life. Therein lies my passion!...MUSIC IS LIFE... |
Posted By: Earplug
Date Posted: 22 February 2017 at 12:36pm
|
"I don't agree, with Viktor, this amplifier has very good sound, it was well designed, bullet proof build." +100 Mine even survived getting plugged into 480v once (yes, I know: Meter Your Mains). The input switch-cum-breaker popped and that's all. After the mains were put back in place, they powered up & worked perfectly. I'd like to see how many (modern) amps could match that. ------------- Earplugs Are For Wimps! |