Hi John,
I have to agree with richie00boy. Nothing wrong with these amps within their power ratings.
A pair of 6.5" woofers per box are not going to move much air. Getting deep bass depends on the room size and the woofer / box size. An amp can't do much if the rest of the system isn't up to the task.
Most amplifiers have no trouble reproducing low frequencies. The differences between them are probably more in the amount of control over the woofer, but not in frequency response.
Your other findings are not terribly surprising, but you may (or may not) notice something after living with the BGs for a while. It's not a break in thing. It's you noticing details over a range of music once you are relaxed.
-Chris
I have to agree with richie00boy. Nothing wrong with these amps within their power ratings.
A pair of 6.5" woofers per box are not going to move much air. Getting deep bass depends on the room size and the woofer / box size. An amp can't do much if the rest of the system isn't up to the task.
Most amplifiers have no trouble reproducing low frequencies. The differences between them are probably more in the amount of control over the woofer, but not in frequency response.
Your other findings are not terribly surprising, but you may (or may not) notice something after living with the BGs for a while. It's not a break in thing. It's you noticing details over a range of music once you are relaxed.
-Chris
Richie00boy, what speakers have you run these amps on?
Chis,
Yes the size of my woofers does worry me, these 782's are 4ohm speakers, will that have any effect?
Apparently they were approx £500 in there day
I think I'm going to do away with the biwiring I could not tell any difference between that and standard -+ wiring.
I was used to big bass sounds on a Rotel ra1412 amp connected to Goodmans RB65 speakers, can't quite remember but think they had 12" woofers, was used to rumbling bass, rubbish speakers but had lots of volume to move air.
I'm going to take my amp to some friends just to see if they play better than whatever amp/speakers they have.
I tried the amp without the psx, maybe snake oil effect here, but I though it was a bit more bassy.
John
Chis,
Yes the size of my woofers does worry me, these 782's are 4ohm speakers, will that have any effect?
Apparently they were approx £500 in there day
I think I'm going to do away with the biwiring I could not tell any difference between that and standard -+ wiring.
I was used to big bass sounds on a Rotel ra1412 amp connected to Goodmans RB65 speakers, can't quite remember but think they had 12" woofers, was used to rumbling bass, rubbish speakers but had lots of volume to move air.
I'm going to take my amp to some friends just to see if they play better than whatever amp/speakers they have.
I tried the amp without the psx, maybe snake oil effect here, but I though it was a bit more bassy.
John
Hi John,
4 ohm speakers are fine on your amplifier.
Bi-wiring is another "one of those things" that some audiophiles jump on. If you have sized your wire properly, bi-wiring is a waste of wire and money.
I have a new pair of "Mono X" amplifiers. I am not using the PSX-R with them. One day I'll have to try this out. Lovely amplifiers.
-Chris
4 ohm speakers are fine on your amplifier.
Bi-wiring is another "one of those things" that some audiophiles jump on. If you have sized your wire properly, bi-wiring is a waste of wire and money.
That's it in a nutshell. You knew this all along in the back of your mind.
Watch out for condensation if your amp gets cold. You must allow it to warm up and dry out before you plug it in. This exercise is much easier in the sumer.
I couldn't say. I am told by customers that they really like the PSX on their equipment.
I have a new pair of "Mono X" amplifiers. I am not using the PSX-R with them. One day I'll have to try this out. Lovely amplifiers.
-Chris
Just thought I would update, and give special thanks to Anatech/ Chris.
Without your help and support my Cyrus would now be gathering even more dust.
As you know I replaced a good few caps, but still thought bass was quite weak, your suggestion that my bass subjectiveness relied on my memory of using larger bass speakers is very true, I guess that is where I based my bass on.
I took my now both repaired Cyrus amps to my brothers, who has a smaller pair of technics speakers, connected to a Cambridge audio A8? amp using his laptop and itunes library as an input to the amp (yea i know).
I listened to his setup with the bass set to flat response, and noted the general timbre of his system.
We then connected my Cyrus and the level of bass was just the same as his no less no more, we increased listening levels, and were very happy with the sound my brother was saying it was just as bassy as his setup.
As, I like bass, we found a graphics equalizer built into itunes application, and was surprised at how much bass we then got, obviously were not talking pure tones now but it proved that the amps were working as suspected.
Went back home and tried my speakers, I found one speaker was lower in volume than the other, removed the bywiring, checked the speaker phasing, which was correct, swapped the left speaker for the right, the problem still followed that speaker.
I took out the drivers and crossover, measured for continuity, and resistance, found that this speaker had slightly worst setting than the other, I then re soldered all the speaker cables and all the crossover connections.
Now, both my speakers are working correctly, the sound is much more rounded, bass is still not how I like it, but it is there, this is not going to change unless I throw much bigger speakers at my system.
This has been very interesting repair project for me, I cannot as Chris suggest notice any difference on one amp built with Black gates, and my other amp filled with less salubrious parts.
Also must mention Geoff for his expert knowledge, and Sonusthree, for been an avid Cyrus fan trying to get his amps to his liking, using various components and experimenting to find his personal preferences.
All I got to do now is get my Cyrus FM7 working, I will be heading off to the Tuner section of diyaudio shortly. 🙂
Regards
John
Without your help and support my Cyrus would now be gathering even more dust.
As you know I replaced a good few caps, but still thought bass was quite weak, your suggestion that my bass subjectiveness relied on my memory of using larger bass speakers is very true, I guess that is where I based my bass on.
I took my now both repaired Cyrus amps to my brothers, who has a smaller pair of technics speakers, connected to a Cambridge audio A8? amp using his laptop and itunes library as an input to the amp (yea i know).
I listened to his setup with the bass set to flat response, and noted the general timbre of his system.
We then connected my Cyrus and the level of bass was just the same as his no less no more, we increased listening levels, and were very happy with the sound my brother was saying it was just as bassy as his setup.
As, I like bass, we found a graphics equalizer built into itunes application, and was surprised at how much bass we then got, obviously were not talking pure tones now but it proved that the amps were working as suspected.
Went back home and tried my speakers, I found one speaker was lower in volume than the other, removed the bywiring, checked the speaker phasing, which was correct, swapped the left speaker for the right, the problem still followed that speaker.
I took out the drivers and crossover, measured for continuity, and resistance, found that this speaker had slightly worst setting than the other, I then re soldered all the speaker cables and all the crossover connections.
Now, both my speakers are working correctly, the sound is much more rounded, bass is still not how I like it, but it is there, this is not going to change unless I throw much bigger speakers at my system.
This has been very interesting repair project for me, I cannot as Chris suggest notice any difference on one amp built with Black gates, and my other amp filled with less salubrious parts.
Also must mention Geoff for his expert knowledge, and Sonusthree, for been an avid Cyrus fan trying to get his amps to his liking, using various components and experimenting to find his personal preferences.
All I got to do now is get my Cyrus FM7 working, I will be heading off to the Tuner section of diyaudio shortly. 🙂
Regards
John
What a great result. And just think how much money you can save on boutique parts and instead spend on stuff that's actually going to make a difference 😀
Hi John,
Thank you, I'm very happy this worked out well for you.
What is wrong with your tuner?
-Chris
Thank you, I'm very happy this worked out well for you.
What is wrong with your tuner?
-Chris
RF interference Cyrus Two
Just would like to thank members of this forum. I had a hum in my Cyrus 2 amplifier (1986) from the mains that was fixed by replacing the two 470uF/50V filter caps. I also replaced the 22uF/35V caps because majority had become faulty. The amplifier sounds great.
However, I still have a problem with radio interference on the right channel. The amplifier by itself plays great. However, when I pug in the PSX I pick up, presumably, an AM station on the right channel. It is low volume, and doesn't change with volume control.
I assume that this is a problem with the Cyrus 2 not the power supply since the power supply would share the interference equally to both R/L channels. I assume that a filtering cap is faulty. Moreover, it is puzzling as to how this signal is demodulated and tuned so that I can hear the station clearly.
Any suggestions/explanations? Thanks
Tam
Just would like to thank members of this forum. I had a hum in my Cyrus 2 amplifier (1986) from the mains that was fixed by replacing the two 470uF/50V filter caps. I also replaced the 22uF/35V caps because majority had become faulty. The amplifier sounds great.
However, I still have a problem with radio interference on the right channel. The amplifier by itself plays great. However, when I pug in the PSX I pick up, presumably, an AM station on the right channel. It is low volume, and doesn't change with volume control.
I assume that this is a problem with the Cyrus 2 not the power supply since the power supply would share the interference equally to both R/L channels. I assume that a filtering cap is faulty. Moreover, it is puzzling as to how this signal is demodulated and tuned so that I can hear the station clearly.
Any suggestions/explanations? Thanks
Tam
Hi Tam,
It is possible there is nothing wrong with your amplifier. One speaker lead may be picking up greater RFI than the other one.
-Chris
It is possible there is nothing wrong with your amplifier. One speaker lead may be picking up greater RFI than the other one.
Each emitter-base connection in the input stage looks like a diode. In other words, an AM demodulator.
-Chris
Hi Chris,
Thanks for the quick reply. I forgot to mention that I swapped speakers from right to left channel. The RF did not swap accordingly, instead it stayed on the right channel regardless. The signal is not being amplified either. Hmm. I am kind of stuck on this one.
Thanks
Steven
Thanks for the quick reply. I forgot to mention that I swapped speakers from right to left channel. The RF did not swap accordingly, instead it stayed on the right channel regardless. The signal is not being amplified either. Hmm. I am kind of stuck on this one.
Thanks
Steven
Also, I only get this RFI when I use the psx in conjunction with the Cyrus 2. I do not have it when I use the Cyrus 2 alone.
Thanks
Tam
Thanks
Tam
Hi Tam,
Time to look at the signal grounds and possibly zobel network.
I have rebuilt many of these and never come across the problem you are having. We used to have a large, high power AM transmitting site close by. Without having your amp on my bench, I can't really say much beyond this.
Try turning the volume control completely down. If you suspect the control, install a shorting RCA plug into an input. Select that input and turn the volume full up. If your problem is on the input side, this should "fix" the problem. You will not tend to listen to it that way.
-Chris
Time to look at the signal grounds and possibly zobel network.
I have rebuilt many of these and never come across the problem you are having. We used to have a large, high power AM transmitting site close by. Without having your amp on my bench, I can't really say much beyond this.
Try turning the volume control completely down. If you suspect the control, install a shorting RCA plug into an input. Select that input and turn the volume full up. If your problem is on the input side, this should "fix" the problem. You will not tend to listen to it that way.
-Chris
I'm not sure if I've just fixed a late Cyrus 1 or an early Cyrus 2. It has an Issue 7 PCB, 3.15A fuses, a big heatsink and a metal casing, but no PSX connector.
The output stage had blown. Specifically, the output transistor Q41. Device = ST 9T939 - Cyrus PT17, and a driver transistor Q31 – a JE243.
I replaced both ST 9T939's with TIP41C's and the JE243 & complimentary JE253 with MJE243 & MJE253. I got all these transistors from ebay: Pack of 10 TIP41C's for £6.50 and 2xMJE243 & 2xMJE253 for about £6 inc. P+P. (I got some spares just in case).
Works fine.
The output stage had blown. Specifically, the output transistor Q41. Device = ST 9T939 - Cyrus PT17, and a driver transistor Q31 – a JE243.
I replaced both ST 9T939's with TIP41C's and the JE243 & complimentary JE253 with MJE243 & MJE253. I got all these transistors from ebay: Pack of 10 TIP41C's for £6.50 and 2xMJE243 & 2xMJE253 for about £6 inc. P+P. (I got some spares just in case).
Works fine.
JoolsB said:
Hello from Sunny Brighton! Small amps .... small world! 🙂
Cyrus 1 and 2 models were made concurrently and all Cyrus two's had a PSX connector.
Are there any gotchas with the work you've done? I've got a Cyrus one with blown (missing!) outputs so it would useful to know if any other adjustments are needed when fitting replacements as you've done. I've got an old scope, basic knowledge, a healthy fear of anything over 12Volts and enthusiasm!
I'm off to check Ebay!
Many thanks,
Small world indeed!
Thanks for the info. It's a friend's amp - he's had it for years.
The first time I fixed it I only replaced the output devices of one side with TIP41C's, and the other side blew up almost straight away when he got it back! It worked fine for me & I suspect one of his speakers did the damage (still to be proven).
Anyway, both sets of outputs are now TIP41C & it's been working without problems for a couple of weeks (on another set of speakers). I don't even have a scope or load these days so I couldn't test it properly, but my friend can't tell any difference sound quality-wise. I'm not sure if he's put it through its paces properly yet, but he has a party coming up soon so if there are any issues at max volume we'll soon find out...
The only minor hassle I had was a bolt that clamps the devices onto the heatsink - easy to strip the thread. A longer one sorted that out though.
Other than the transistors, I didn't change any other components.
If we find any problems I'll do another post. Good luck.
MJE243/253
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=170231323239
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=170231323452
TIP41C
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=230325875203
Thanks for the info. It's a friend's amp - he's had it for years.
The first time I fixed it I only replaced the output devices of one side with TIP41C's, and the other side blew up almost straight away when he got it back! It worked fine for me & I suspect one of his speakers did the damage (still to be proven).
Anyway, both sets of outputs are now TIP41C & it's been working without problems for a couple of weeks (on another set of speakers). I don't even have a scope or load these days so I couldn't test it properly, but my friend can't tell any difference sound quality-wise. I'm not sure if he's put it through its paces properly yet, but he has a party coming up soon so if there are any issues at max volume we'll soon find out...
The only minor hassle I had was a bolt that clamps the devices onto the heatsink - easy to strip the thread. A longer one sorted that out though.
Other than the transistors, I didn't change any other components.
If we find any problems I'll do another post. Good luck.
MJE243/253
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=170231323239
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=170231323452
TIP41C
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=230325875203
Good stuff JoolsB!
I have a couple of these amps (Cyrus one/Two/PSX) in my main system and it seems a shame to have another one stashed under the bed, lifeless.
Thanks again! 🙂
I have a couple of these amps (Cyrus one/Two/PSX) in my main system and it seems a shame to have another one stashed under the bed, lifeless.
Thanks again! 🙂
Yes, lifeless amps are wrong.
I'd offer you the spare transistors but they're in Rye with the amp..
I'd offer you the spare transistors but they're in Rye with the amp..
Cyrus 2 Blown Again
Hey gents, been quite a trail with my Cyrus 2. Had this baby for almost 20 years now. Love the amp, hate it's over sensitive nature to shorts
So, once again, something is blown.
Fuse FS1 has blown but not the other. Still nothing coming out of both output terminals. I checked the voltage at all 4 output transistors and 2 out of 4 give me a reading of aprox 33.3 V. (my multi meter is a low quality general purpose unit ..but it's all I have)
Q42 = 0 V
Q44 = 33.3 V
Q41 = 0 V
Q43 = 33.3 V
Are Q42 and Q41 dead?? And what else should I check to confirm that if it is indeed only the OT??
Thanks in advance!
Ben
Hey gents, been quite a trail with my Cyrus 2. Had this baby for almost 20 years now. Love the amp, hate it's over sensitive nature to shorts
So, once again, something is blown.
Fuse FS1 has blown but not the other. Still nothing coming out of both output terminals. I checked the voltage at all 4 output transistors and 2 out of 4 give me a reading of aprox 33.3 V. (my multi meter is a low quality general purpose unit ..but it's all I have)
Q42 = 0 V
Q44 = 33.3 V
Q41 = 0 V
Q43 = 33.3 V
Are Q42 and Q41 dead?? And what else should I check to confirm that if it is indeed only the OT??
Thanks in advance!
Ben
There's not much point trying to measure anything if you have only one side of the supply present.
I would change output devices as a matter of course and also the drivers. When you take the old ones out measure their resistance collector to emitter and the duds will be low resistance.
I would change output devices as a matter of course and also the drivers. When you take the old ones out measure their resistance collector to emitter and the duds will be low resistance.
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