Latest Thread Images

the CTH (Compact Tube Hybrid) Rev A thread...
May 22, 2011 at 5:03 PM Post #181 of 607
Some ideas for replacement parts, just hoping that you guys can verify that these will work.

Fuse Holder
Replacement: http://www.mouser.com/ProductDetail/Littelfuse/03455LF2H/?qs=sGAEpiMZZMukmSYeDOiaDK82%2fMbOC9l01cigQ%2fERqRw%3d

Capacitors:

Original: http://www.mouser.com/Search/ProductDetail.aspx?R=UVR1H101MPD1TAvirtualkey64700000virtualkey647-UVR1H101MPD1TA
Replacement: http://www.mouser.com/ProductDetail/Nichicon/UKW1H101MPD/?qs=sGAEpiMZZMtZ1n0r9vR22e0BBN1kF1oiucpIJyTTRQM%3d

Resistors:

Original: http://www.mouser.com/Search/ProductDetail.aspx?R=299-6.8-RCvirtualkey21980000virtualkey299-6.8-RC
Replacement: http://www.mouser.com/ProductDetail/Vishay-Dale/RN55D6R81FB14/?qs=sGAEpiMZZMsPqMdJzcrNwmmyJH8x4%252byIKMd71bZ7Q08%3D

Still looking for a heatsink replacement.

Also unsure about the relay. It should be in stock on the 30th, and though I would like to place an order today (for the meet this weekend) it wouldn't kill me to wait until then.


 
May 23, 2011 at 1:06 PM Post #182 of 607
Your suggested subs look fine to me as they match value/rating/size/type/lead-spacing... I guess you've also seen the subs/corrections/suggestions for other parts in this thread (& the GB one).   The relay may be tricky to sub, but I've not tried searching yet.
 
May 23, 2011 at 2:26 PM Post #183 of 607
May 23, 2011 at 4:53 PM Post #184 of 607
 
 
 

[size=medium]
In reading on the web [1] and on headfi [2], it seems that the carbon film resistors may have more pink noise, but that this may be "pleasing."  Would anyone care to comment specifically on the CTH?  Thanks so much,
 
-c
 
[1] http://www.aikenamps.com/ResistorNoise.htm
[2] http://www.head-fi.org/forum/thread/260846/metal-vs-carbon-resistors-what-is-the-difference
​
[/size]

 
May 25, 2011 at 4:33 PM Post #185 of 607
Hopefully Alex will chime in - when I helped the original BoM, I asked this question, and I thought he said there is a reason these should be carbon for a reason. They're mighty wee little buggers...
 
 
May 25, 2011 at 7:30 PM Post #186 of 607
He's got about a day to get in here before I just give in and buy the RN55Ds, like every other resistor on the board... It could very well be a heat issue though. Carbon film resisters can tolerate higher heat, if I recall correctly. I might try these instead.
 
May 25, 2011 at 10:30 PM Post #187 of 607
If you're going to use RN55s, you might as well get 1/4 watt carbon films, there are plenty available that are about the same size as RN55s:
 
http://www.mouser.com:80/ProductDetail/KOA-Speer/CF1-4CT52R6R8J/?qs=sGAEpiMZZMu61qfTUdNhG1dhquwH4o0FfRLFhWtWO%252bc%3d
 
OR I have at least three sets of 8 - you could PM me your address and I'll mail you a set... 
wink.gif

 
 
 
May 27, 2011 at 7:50 AM Post #189 of 607
Gents, my apologies for being slammed with work and the LF.
 
It's ok to use metal film resistor for the 6.8R values.
 
Also, for those of you who are having e12 trip issues, you can try increasing the value of R1E and R2E. This will desensitize the e12 and cause it to trip at higher voltages.
 
Here's the way to approximate what will happen.
 
The tripping voltage is approximately equal to: 600mV * R1E / R3E.
 
With the current values this is: 600mV * 33k / 100k = 200mV.
 
If you change R1E (and R2E) to 100k the e12 will trip at approximately 600mV.
 
What is acceptable to you depends on your headphones.
 
For example, 600mV with 300R headphones is only a DC current of about 2mA. This will not be a continous current because the servo will keep the DC offset near zero, but it can exist as a transient current for tens of ms before the e12 unlatches.
 
For 32R, 600mV is more like 20mA. Most headphones can handle more than 20mA signal simply to drive them so they won't harmed by this as long as it doesn't happen continously (which it wont', again, because the servo will zero the offset and/or the e12 will cut out if the 20mA persists).
 
Obviously, you can select any voltage that you want. 68k will trip at apprxoimately 400mV. Etc.
 
I hope this helps with some of these problems.
 
Jun 24, 2011 at 12:17 PM Post #192 of 607
Just wondering if there's any (dis)advantage if I bump the C4L/C4R to 0.47uf? Just found some 0.47uf Vit Q in the parts bin and they seem to fit just fine, not really any bigger than the 0.22uf that I thought of using.
 
Jun 24, 2011 at 10:14 PM Post #193 of 607
I will receive my CTH tomorrow. I was curious if changing the in/outs to 1/4 from 1/8 jacks would be possible. I don't have any DIY skills so I'm sure it would probably be a tuff task for me. Kinda wish I would have asked more questions before I bought it but i didn't. It was built by stringgz awhile ago. Anyway, I'm still pretty excited to get it though.
 
Jun 24, 2011 at 10:44 PM Post #194 of 607
schwallman said:
I will receive my CTH tomorrow. I was curious if changing the in/outs to 1/4 from 1/8 jacks would be possible. I don't have any DIY skills so I'm sure it would probably be a tuff task for me. Kinda wish I would have asked more questions before I bought it but i didn't. It was built by stringgz awhile ago. Anyway, I'm still pretty excited to get it though.
Click to expand...


http://www.radioshack.com/product/index.jsp?productId=2062467
 
Jun 25, 2011 at 1:45 AM Post #195 of 607


Yeah I have one and I guess I need to go pick up another tomorrow. I guess adapters will work for now but I will eventually want to switch them out on the cth if I can. If not I will atleast have an amp to look at and study and hopefully be able to build my own. I know it was built way before the rev a specs. Did the original cth call for the 1/8 input/output? I cant imagine why this would be the only option the original builder went with.
Quote:
jdkjake said:
Quote:
schwallman said:
I will receive my CTH tomorrow. I was curious if changing the in/outs to 1/4 from 1/8 jacks would be possible. I don't have any DIY skills so I'm sure it would probably be a tuff task for me. Kinda wish I would have asked more questions before I bought it but i didn't. It was built by stringgz awhile ago. Anyway, I'm still pretty excited to get it though.
Click to expand...




http://www.radioshack.com/product/index.jsp?productId=2062467
Click to expand...



 
 
You must log in or register to reply here.

Users who are viewing this thread

Total: 4 (members: 0, guests: 4)
Back
Top