Audcom Preamp mods

Wayne1 · « **on:** 22 Mar 2004, 05:58 pm »

I have finished up the mods to this inexpensive tube preamp that Andrew http://www.sekei.com sells. I replaced all of the signal wiring, all of the coupling caps with SoniCaps. Upgraded the PS cap, replaced the resistor networks with Riken-Ohm and added a couple of Bybee Slipstream Purifiers to the output.

It is still breaking in. Hopefully the DAM might be able to take a listen to it before it is on it's way off to it's new owner.

mgalusha · « **Reply #1 on:** 22 Mar 2004, 06:00 pm »

I'd love to hear it. Maybe we can convince Jerry to host since he's been on a preamp quest.

Mike

maxwalrath · « **Reply #2 on:** 22 Mar 2004, 06:28 pm »

Wayne, what's the cost?

ooheadsoo · « **Reply #3 on:** 22 Mar 2004, 06:30 pm »

Anything finalized yet about pricing and options for breaking down the upgrades into smaller chunks? Some people (like me) may not be able to afford the bybees.

Wayne1 · « **Reply #4 on:** 22 Mar 2004, 07:51 pm »

If you have to ask.....

The mod price without the Bybees is around $300.00

Mike,

Jerry just listed his house for sale. I am not too sure how good a listening session it would be with realtors and potential buyers wandering in and out while we are listening to "Poems of Thunder"

mgalusha · « **Reply #5 on:** 22 Mar 2004, 09:26 pm »

Quote from: Wayne1

Jerry just listed his house for sale. I am not too sure how good a listening session it would be with realtors and potential buyers wandering in and out while we are listening to "Poems of Thunder"

He told me it was going on the market but I didn't realize it would be so soon. Yea, I think Poems of Thunder might cause distress in potential buyers.

I'll volunteer to host if anyone else in the DAM is interested. How much longer do you anticipate having the pre before shipping it off to it's new home? I wonder if Tyson will be interested since he's moving to an all digital system? I'll check with my wife to see if we're supposed to go anywhere this weekend or next. I can't ever remember, good thing she keeps notes.

I'll give you a call to discuss options Wayne.

Mike

Marbles · « **Reply #6 on:** 22 Mar 2004, 09:30 pm »

You guys can't talk Tyson into a good TT setup????

Sucks for him

Wayne1 · « **Reply #7 on:** 22 Mar 2004, 09:43 pm »

Tyson is a young punk who hates all music recorded before digital was introduced

What do you expect from a guy who thinks Eminem is the ultimate lyricist

He also has no room for vinyl in his apartment.

Besides, he gets all his music from the library and burns copies. He is far too cheap to actually BUY any music

ooheadsoo · « **Reply #8 on:** 22 Mar 2004, 11:30 pm »

Looks like I'm not going to be able to afford even the basic upgrade package for quite a long time. Is the stock audcom good enough to be able to live with it for a while, considering I don't have super good gear in the first place? It would be replacing a cheapo passive preamp. Also, I have heard of people rolling in the 12au7 and liking the preamp a lot more. Can this be done as a drop in replacement without any mods?

Wayne1 · « **Reply #9 on:** 22 Mar 2004, 11:42 pm »

Trying to access the tubes in the stock unit is a major PITA. You have to remove just about every screw on the unit and do some really strange contortions to the metal work.

As part of the mods I cut the top of the cover off the tube compartment so the end user can easily tube roll. The stock unit isn't bad. It does have very high gain, which is why some folks change to a 12AU7. The mod takes care of the gain problem.

When we listened to the stock unit, we commented that it was soft on the top end and light on the low end. The phono stage is fairly hideous. It just uses a single 5532 op-amp. I bypassed the phono section in this unit at the customer's request.

ooheadsoo · « **Reply #10 on:** 23 Mar 2004, 03:38 am »

Thanks for letting us know, Wayne.

Obviously, you guys immediately thought that the audcom is a bargain and worthy of modding. I guess what I'm trying to get down to is...if you only had $300 to spend, would this preamp be on the short list?

vrs · « **Reply #11 on:** 23 Mar 2004, 03:47 am »

I donot think Andrew of sekei got any Audcom 120a vailable at this time, but I guess they are on order and will be available soon.

I know at least one ownerof 120 is happy with tube rolling , damping and plans toget it upgraded after this pre amp is upgraded.

I have 2 other AVA pre amps
I am not in a hurry to get this pre amp back and can wait till DAM listened to it.

Wayne1 · « **Reply #12 on:** 23 Mar 2004, 02:11 pm »

This preamp is on MY short list. I am looking for something for my office vinyl rig.

My other contenter is the new Hagerman preamp. I really do not care for the case on the Hagerman, but because it is a kit I could use just about anything.

I do believe the Audcom is a true bargain. In it's stock form it is a very good deal. Once modded, I think it will be even better.

ooheadsoo · « **Reply #13 on:** 24 Mar 2004, 12:19 am »

Very cool. The Hagerman certainly doesn't look like it will fall short of the Audcom's price, though quality may be a different matter.

I believe you said you fixed the high gain issue. Can you tell us if you made the gain fixed and the value or values of the gain after your mods?

Wayne1 · « **Reply #14 on:** 24 Mar 2004, 12:35 am »

I changed the resistor values that control the gian through the switch on the back. I left the 0 gain setting alone, aside from improving the resistors.

The other 2 settings are about -7.5 and - 15 db now.

ooheadsoo · « **Reply #15 on:** 24 Mar 2004, 01:10 am »

I think the audcom has blown the bottlehead foreplay out of the water for my short list. I'm going to have to save up to get this and if I like it, save up again to get it modded by you, Wayne.

By the way, any hissing or hum issues with it? I listen in the nearfield so I'm pretty sensitive to it.

Wayne1 · « **Reply #16 on:** 24 Mar 2004, 02:46 am »

So far I have used this preamp with an old Hafler DH-220, Radii EL-34 tube mono blocks, and the little Power Wave Tripath based digital amp. No hum or hiss. I have used Scan-speak driver based speakers and the 90 dB plus Horn Shoppe Horns.

ooheadsoo · « **Reply #17 on:** 24 Mar 2004, 02:49 am »

This is starting to sound too good to be true

Next thing I know, you'll be telling me it has tape outs so I can hook up my headphone amp without a hassle!

Thanks for the quick replies, Wayne.

Wayne1 · « **Reply #18 on:** 24 Mar 2004, 03:00 am »

Sorry, no tape outs.

BUT, if you wave enough money in my general direction, I could install a pair

ooheadsoo · « **Reply #19 on:** 24 Mar 2004, 03:10 am »

Exactly what I wanted to hear